e
YOUR ELECTRONICS MAGAZINE
06
Watching Us Watching Them The Future of the User Interface rswww.com/electronics
ISSUE 4
SWITCH TO APEM Apem is an established name in switches synonymous with innovation, quality and reliability. Approved to most European and International standards, APEM can provide PCB and panel switches membrane and stainless steel keypads, LEDs, panel indicators and joysticks that any designer can specify and feel secure using. APEM have established facilities worldwide providing technical assistance and availability.
rswww.com/apem
PUSHBUTTONS FOR HARSH ENVIRONMENTS
IR SERIES - Sealed to IP67 - Non-illuminated or illuminated - Momentary, Latching Rear Mount Versions - Square or Round Bezel Actuator - Wide choice of Actuator colours - Wide choice of illumination colours - Wired, Solder or Screw Terminals - Microswitch Versions Rated to 5A 250V AC - Screw Terminals Rated to 2A 250V AC
CA PABI TIES LI
4
2
CE USER INTERFA
G SWITCHIN
FO R4 G
06
14 GET READY
Welcome to your latest edition of eTech. The theme for this edition is user interface and mobile technology, with a focus on the future of UI, 4G and batteries for mobile designs. We’ve also introduced a new ‘Market Trends’ feature in conjunction with iSuppli, where we look at future technology trends and the growing use of motion sensors in mobile phones - see page 22. The world of electronics technology is evolving rapidly and nowhere is this more apparent than on the DesignSpark.com forums and blogs. DesignSpark.com is the gateway to online resources and design support for engineers, powered by RS. DesignSpark.com provides us all with an ideal forum to keep up-to-date with the latest trends, tools and hot topics and some of these have shaped this edition.
Terms and conditions: Terms and conditions of sale set out in the current RS Catalogue. This issue is valid from October 2010 to December 2010.
Published by: RS Components Limited. Registered office: Birchington Road, Weldon, Corby, Northamptonshire NN17 9RS. Registered No. 1002091. RS Components Ltd 2010. RS are trademarks of RS Components Limited. An Electrocomponents Company.
Feedback from you indicates that you want to see more Design Reviews. So we have extended this feature with the ARM mbed review on page 20 and the Embedded Systems review on page 34. We are now more connected with you than ever before! Keep in touch with us through DesignSpark.com or email me at
[email protected]. Glenn Jarrett Head of Electronics Marketing
INSIDE eTech 04 05 06 10 12 14 16 20
22
24 26 29 32 34
38 40 42 ELE_0010_1010
iSAY RS NEWSLINE FUTURE OF THE USER INTERFACE PRODUCT NEWS BATTERIES FOR MOBILE DESIGNS GET READY FOR 4G LANE DETECTION DESIGN REVIEW: ARM mbed MARKET TRENDS: Motion Sensors SWITCHING CAPABILITIES EPD UPDATE : WIRELESS DESIGN TIPS: ELEKTOR Electronics Extras DESIGN REVIEW: EMBEDDED SYSTEMS CUSTOMER PROFILE LUNCH BREAK INDUSTRY NEWS: FRAUNHOFER eTech - ISSUE 4
03
iSAY
RS NEWSLINES
PROF. FERNANDO AGUADO, UNIVERSITY OF VIGO, SPAIN SAYS:
“
3D CAD Library from RS continues to grow
Why there’s
no time like the present to get into
The European Space Agency’s new low-cost launch vehicle, Vega, heralds “the democratisation of space” – and exciting opportunities for electronics companies to become involved.
Here’s how. Smaller satellites make it realistic to carry out missions that would have been inconceivable just a few years ago. CubeSats, one of the most popular standards for small satellites, allow scientists to carry out experiments in space with very modest budgets. The design of a single satellite traditionally involves massive expenditure, long periods of design and testing, and an extensive specialized team, but CubeSats change the rules completely. They are smaller and simpler, cheaper to launch, and a small team of engineers can develop in years, rather than decades. Lower launch costs and smaller payloads make it economical to fly shorter missions - and more of them. In turn, this means that electronic components on board don’t need to be radiation hardened, nor undergo time-consuming, costly space qualification. Commercial, off-the-shelf components can be used instead. In this “virtuous circle”, modern COTS will help meet the tight mass, power, and dimensions constraints in CubeSats, and at lower cost. It all combines to make CubeSat highly competitive for commercial
04
eTech - ISSUE 4
”
space
For example, the XATCOBEO project, a joint research project between INTA and the University of Vigo includes three exciting and challenging experiments: an in-flight reconfigurable radio based on standard FPGAs, a radiation dose sensor and a panel deployment mechanism. This pioneering work will pave the way for many future small-satellite projects where the University of Vigo has a pivotal role: like HUMSAT - a low-cost global communications infrastructure for humanitarian aid and disaster or climate change monitoring; GENSO a worldwide network of education and radio amateur ground stations; and the European Student Earth Orbiter (ESEO) and European Student Moon Orbiter (ESMO). In all of these, the use of COTS components will provide opportunities for the European electronics industry to test its technology and play its part.
RS introduces 3D CAD models from more manufacturers
Silicon and Development Kits add ultra low power choice to ARM portfolio at RS
In a major expansion of the 3D CAD programme, RS introduces an additional 5000 new models available to download from its website. Models from key manufacturer Tyco Electronics include the popular Mate-n-Lok and MODU ranges, along with high speed Z-Pack and Multigig connectors. Also introduced are a series of sensor and relay models from Schneider Electric, ideal for use in safety equipment designs.
Adding Energy Micro to the already comprehensive range of ARM devices at RS brings the world of ultra-low power applications in to the hands of Design Engineers everywhere. This range expansion will include 128k Flash versions of all devices in the Gecko product family. Alongside the silicon, both the Gecko and Tiny Gecko development tools will be available allowing designers to put the advanced 32-bit Cortex
With this expansion, RS now offers a huge number of 3D CAD models in over 20 different file formats to suit all of the most popular 3D design software suites. All models are available to download free-of-charge, ready to be incorporated into your new design. To download 3D models from RS, visit rswww.com/3d.
applications. Also, these smaller satellites will train new engineers in space technologies, and make space missions affordable for many fields of research.
Energy Micro Cortex M3 range now available. M3 core and its integrated lowpower peripherals to the test. The combination of Ultra-low power and industry standard core should prove to be a compelling one for energy conscious engineers everywhere.
For detailed information, visit rswww.com/electronics
Development kit and accessories offer doubles to over 1,300 RS recruits development kit reviewers
RS sign new distribution agreement with Bourns Partnership covers EMEA and APAC, adding to existing US agreement
“
Lower launch costs and smaller payloads make it economical to fly shorter missions and more of them.
”
If you’ve got a strong opinion and would like the opportunity to get on your soapbox, write it up in around 300 words and email it to
[email protected]
The partnership with Bourns, a leading manufacturer of passive components, formalises the long-standing relationship with RS. The two companies will be working together on a series of initiatives covering range developments and promotional activities, to be carried out on a global basis. Over 700 new products have been added to the RS range, including TBU™ high speed protection components.
More details can be found at rswww.com/bourns
A significant investment by RS in leading edge development tools has seen the development kit and accessories offer expand to over 1,300. Now RS is actively looking for reviewers to contribute to the growing database of independent reviews on DesignSpark.com. To view the full range of development kits on offer, visit rswww.com/developmentkits If you are interested in writing and posting a review, email your details to etech@rs-components. com and we will send you details of how to obtain a development kit free of charge.
eTech - ISSUE 4
05
Watching Us Watching Them The Future of the User Interface Designers of home computing and consumer technology know that success relies heavily on delivering the most outstanding user experience. Game consoles, smartphones and even PCs are evolving quickly to provide seamless, intuitive interactions that consumers not only demand, but also need if they are to make best use of increasingly diverse and powerful features. To make it happen, designers are “disappearing” the technology.
Growth of touch Mechanical knobs, dials and sliders, which were commonplace even on portable music players as recently as the last decade, have quickly become ancient history. Mobile phones introduced the concept of soft keys to enable context-sensitive access to large numbers of features and options. Current MP3 players and mobile handsets have taken the concept further to deliver an even more flexible user interface featuring capacitive touch sensing. More recently still, smartphones with multi-touch capability have begun enabling users to interact even more freely and naturally with their gadgets. Basic two-touch sensing allows features such as pinchto-zoom, allowing people to experience and share the increasing variety of content now available on mobile handsets more spontaneously and naturally than ever before. Just around the corner, true multi-touch, capable of decoding ten or more touch points simultaneously, hints at a vast new world of single-user and multi-user applications; not only on equipment such as handhelds and game terminals, but also in professional applications such as drawing packages, management/logistics software, and tools for collaborative design. To enable the next technology leap for touchscreens, UK-based Peratech has developed a cost effective pressure-sensing touchscreen technology which differentiates between gentle touch and a hard poke. Using what’s called the Quantum Tunnelling Composite (QTC), a touchscreen display can very efficiently detect where, and how hard the screen is being pressed. Peratech’s QTC changes the game Continued page 08>
06
eTech - ISSUE 4
eTech - ISSUE 4
07
< Continued from page 06 when it comes to human machine interface design with capabilities to build truly 3D user interfaces in small, low power devices. Using products with an embedded QTC switch consumers could use this third dimension to search deeper into a file structure simply by pressing harder, control an avatar’s movement through a game more naturally, or create the thin or thick lines which are vital for Far East characters. Optical sensing Despite howls from some selfconfessed geeks and couch potatoes, disappearing technology is also having a significant effect in the gaming sector. Nintendo Wii, featuring MEMS motion sensors embedded in wireless handsets, took user interaction to a higher level than was possible with the traditional gamepad featuring button and joystick control only. The recent announcement of Microsoft’s Kinect for Xbox 360 claims to advance the concept of ultra-accessible and compelling gameplay even further. Kinect uses optical sensing and recognition technologies developed by the Israeli company PrimeSense to realise what some
“
More recently still, smartphones with multitouch capability have begun enabling users to interact even more freely and naturally with their gadgets.
”
consider as being the ultimate game controller – the player’s own body.
Optical 3D sensing can be done in a number of ways. Some systems detect the position of the user’s body or limbs by calculating the “time of flight” for a pulse of light. PrimeSense uses what it calls
08
eTech - ISSUE 4
“light coding”, at wavelengths close to infrared, to compute depth-of-field data. The resulting absence of lag means this approach is well suited to highspeed consumer devices. PrimeSense’s 3D capture system shows how visual recognition, drawing on components such as CMOS image sensors can allow machines to respond to users’ movements. Sensed actions can be replicated on screen and used to determine subsequent events in the game; no handheld or even wearable controller is needed. Building on the concept of motionaware gaming, which Nintendo Wii cemented into the collective consumer consciousness, PrimeSense’s technology heralds another significant milestone: the age of the controller-less controller. The notion is poised to reach significantly beyond gaming, however. PrimeSense envisages television viewers using hand movements, instead of a traditional remote, to select channels, browse interactive features and access online services. The company’s CEO, Inon Beracha, has said the technology enables a paradigm shift in the way people interact with consumer electronic devices. In fact, PrimeSense’s goal, through its recognition technologies, is to enable users to control and interact naturally with devices in a simple and intuitive way. Implications for professional technology This, of course, is where many owners of professional technology – such as industrial, medical and office equipment - would like to go. Achieving a more natural and intuitive user experience is seen as being central to helping business owners increase their productivity, reduce training overheads, and avoid cost contributors such as stoppages and human errors. It is also important to note that today’s equipment operators expect a better user experience; as increasingly tech-savvy consumers, they are accustomed to easy interaction with devices
at home and on the way to work; why should they then spend their working day struggling with cumbersome, unrewarding industrial technology? The benefits of good ergonomics in industrial design are, of course, already understood. Equipment designers have drawn heavily on existing PC technology, for example, not only to benefit from the advanced processing capabilities and economies of scale that are available but also to take advantage of user-interface advances such as menus and pointers – and, more recently, touchscreen capability. Examining some of today’s most advanced machines, such as production-line equipment for electronics manufacturing, shows how simplified graphics and touchscreens are being used successfully to help users set up complex processes quickly and accurately, despite economic pressures that are forcing employers to provide the briefest, most cursory training. Extensive use of pictorial – rather than text-based – instructions also overcomes language barriers, which brings benefits for equipment owners as well as vendors in today’s globalised economy. Taking a fresh look at important advances in the consumer sector – and particularly technologies such as multi-touch, motion sensing and 3D optical techniques – could inspire future generations of professional equipment designers to deliver even more productive, easy to use and rewarding designs in the future.
switch solutions Omron
Introducing the New A9 series of Switches This new range of switches from Omron has a see-saw mechanism that offers high contact reliability combined with a quick electrical changeover that minimises risk of sparks and chattering. ■ Two-point clip contact mechanism combined with see-saw action ■ Gold-plated clip contact and cleaning mechanisms ensure high reliability ■ Specially designed to prevent grease entering the contact area ■ Sealed against flux entry and a built-in ‘O’ ring ensure immersion washability ■ Washable Models (IP64)
A9P Push Button Switch Available with straight, right-angle or vertical mounting, with or without a 5mm cap top. A9S Slide Switch This switch is available with two positions (changeover) or three positions (off-on-off). A9T Toggle Switch Offered in momentary and latching form with two or three positions and a standard, flat or antielectrostatic actuator. It is also available with straight, right-angle, vertical or bracket versions.
Find the latest introductions from RS to support new user interface designs for applications at rswww.com/electronics
Omron’s range of switches includes quality, precision microswitches satisfying most industries, tactile switches featuring the industry’s smallest positive click action switch and DIP switches to suit most production processes.
Omron designs operability, user-friendliness and customer benefits into all of its switches. Visit www.omron-rs.eu to view the range
PRODUCT NEWS
product NEWS
Agilent 33500 Series WAVEFORM Generator Agilent Technologies Announces 30 MHz Function/ Arbitrary Waveform Generators with Unparalleled Signal Accuracy compact connections. n Agilent 33500 series of waveform generators deliver the lowest total harmonic distortion, true point-by-point arbitrary waveforms, lowest jitter in their class for the most challenging measurement applications.The generators include USB 2.0 , LAN (LXI-C) and GPIB (optional) for quick and easy connectivity to a PC or a network. Online search term: Agilent, 30MHz
JTAG programming and boundary-scan testing products Increase your coverage with JTAG master n JTAGMaster is a Boundary Scan Tester and In-System Programmer from ABI Electronics. The ABI JTAGMaster is a complete and powerful solution for the testing, faultfinding and programming of complex PCB assemblies with JTAG devices. Online search term: JTagMaster
RS THERMAL INTERFACE
Molex Mini-Fit H20 range
Allowing the efficient conduction and management of heat away from sensitive components
The sealed Mini-Fit H2O™ IP67-rated system meets the need for weatherproof, compact connections n The Mini-Fit H2O™ mid-range power connector is designed for use in weatherproof applications. It has a small overall profile and can handle up to 9.0A per circuit. Online search term: molex h2o minifit
n RS Components is delighted to introduce a range of thermal interface materials, gap fillers, greases and gels. The range offers good value without compromise in performance. Online search term: RS Thermal Interface Material
RECOM REC3.5 and REC6 isolated DC/DC converters Re³inforced DC/DC Converters offer up to 10kVDC isolation compact connections
Desco EMIT Bench Top Zero Volt Ioniser Zero Volt ESD equipment for handling of sensitive electronic components n Ionization systems provide neutralization of charges on items such as circuit board materials and some device packages. The ionisers from Desco Emit are very small in size, have two fan speeds, have visual and audible power and alarm indicators and come with a 5 year manufacturer’s warranty. Online search term: ESD zero ioniser
n The Recom Re³inforced range offer users the triple bonus of reinforced isolation, high isolation voltage and high efficiency. The REC3.5-R8/R10 offers 3.5W of power and the REC6-R8/R10 offers 6W of power, both with 10kVDC of isolation in a DIP24 package. Online search term: recom, rec35*, rec6*
NEW Cost effective passive components from RS RS Series of Thick Film Resistors, 0402 / 0603 / 0805 / 1206 format
Schaffner inlet filter 9244x series
n RS Series of Thick Film Resistors, 0402 / 0603 / 0805 / 1206 format, RS Thick Film Chip Resistors have anti-surge characteristics superior to standard metal film resistors and are very reliable. They are suitable for both reflow and flow soldering operation with a consistent size to allow pick and place machines to be used. Online search term: RS Resistor
FN 9244 Excellent performance IEC inlet filter n The FM9244 series of IEC inlet filters from Schaffner provide excellent performance and are a practical solution helping you to pass EMI system approval in a short time. These filters combine an IEC inlet and mains filter with superior filter attenuation in a small form factor. Online search term: schaffner FN9244*
Microchip MCP2200EV-VCP Hall Effect Joysticks from Apem Contactless joysticks for harsh environments n The 3000 Series are high precision contactless joysticks. It is available in one, two or three axes formats. Long trouble-free life is assured with the latest hall effect technology. Online search term: Heavy duty Apem
10
eTech - ISSUE 4
MCP2200 USB to RS232 Development and Evaluation Board n The MCP2200EV-VCP is a USB to RS232 development and evaluation board for the MCP2200 USB to UART device. The accompanying software allows the special device features to be configured and controlled. The board is powered from USB. Online search term: Microchip MCP2200*
See more online - Over 5,000 new products are added at rswww.com/electronics every month
RS Series of Carbon Film Leaded Resistors, Axial 0.25W / 0.5W / 1W / 2W format n The RS Carbon Composition Resistors consist of a solid cylindrical resistive element with embedded wire leads to which the wires are attached. The body of the resistor is protected with paint or plastic polymers then colour coded with its value. Online search term: RS Carbon Resistor
eTech - ISSUE 4
11
Batteries live longer for mobile designs By Vincent Bannigan Product Manager, RS Components
As mobile devices continue to evolve, they are becoming smaller and smarter. Today’s higher performance mobile processors demand ever-greater power; and users want longer-lasting, faster-charging batteries, in ever smaller and lighter packages. The batteries for use in these applications continue to develop with higher energy densities, as manufacturers apply new rechargeable chemistries such as lithium-ion and lithium polymer to professional and industrial devices as well as consumer products. Not to be confused with the non-rechargeable lithium primary cells, lithium-ion batteries are justifiably popular for portable consumer electronics, as their energy-to-weight ratios
12
eTech - ISSUE 4
are amongst the best, they suffer no memory effect, and lose their charge slowly when not in use. Beyond these advantages, lithium ion batteries are increasingly recognised for military, electric vehicle, and aerospace applications because of their high energy density. Manufacturers are making a string of R&D improvements to the technology, focusing on energy density, durability, cost, and safety. For example, Enix Energies offers RS
customers a range of Li-ion batteries in cylindrical and flat prismatic hard and soft-pack formats, delivering between 3.7V, 1840mAh and 15V, 6800mAh in packages of up to 12 cells. All provide high energy density and long cycle life, require no maintenance and have built-in circuit protection Improving on Lithium-ion Lithium polymer technology is a further development from lithium-ion batteries, in which the lithium-salt electrolyte is held in a
solid polymer composite rather than an organic solvent, as is the case with Li-ion. Advantages of this approach include lower manufacturing cost, more rugged construction and wider adaptability to different packaging shapes. This means that, as with Lithium Ion battery cells, they can be used to construct battery packs in a huge variety of voltages and capacities, all of them ultra-lightweight in relation to their capacity. Varta’s innovative EasyPack range, based on their leading PoLiFlex® technology, offers a high performance, ready-made, cost effective solution. The expanding RS catalogue includes four 3.7V EasyPack modules with capacities up to 2000mAh. And designing could not be simpler, thanks to the availability of an EasyPack Charging Evaluation Kit. This comes complete with a sample of each of the EasyPack range; plus a plug in power supply, open PCB-mounted charger circuit and connector set. Based on the Texas Instruments BQ24014 charge management chip, the kit also incorporates 14 test pins to make it easy to perform measurements and add elements to the circuit. Battery innovations are set to continue,
powered by battery manufacturer’s everstronger R&D efforts, according to Herbert Schein, Managing Director and CEO at VARTA Microbattery, “There is a continuing increase in more powerful batteries, for example in the area of rechargeable batteries there is a need for technically advanced and well-engineered energy storage. VARTA Microbattery meets these requirements with fundamental research.” The challenges of the future will be met by a strengthened team in a new research and development centre.
cells, ensuring that there is always the perfect solution for any application. Regardless of technology, the fundamental questions remain the same for the designer: finding the solution that best meets the requirements of size, voltage, current, duration, weight, temperature range, recharging, environmental and safety considerations.
The right choice – the widest range Despite this, traditional solutions may still prove best for some applications. The limited output current of Li-ion and Li-polymer batteries may be a drawback, especially with need for a protection circuit module. Also transportation issues need to be considered with lithium chemistries. Often there is a more suitable solution provided by more traditional technologies: for example a 2.7kg pure lead battery can produce over 300A. It’s hand portable yet powerful enough to start a large vehicle. RS stocks literally hundreds of different battery types, from dozens of manufacturers, ranging from coin back-up batteries to lead-acid primary
Find a complete range of batteries suitable for mobile devices at rswww.com eTech - ISSUE 4
13
Get ready for
4G “
Fourth-generation (4G) wireless has got off to a quiet start but the migration to a faster mobile internet is already underway. Cities such as Atlanta, Chicago and Las Vegas already have 4G services in place and US operator Sprint is gradually adding cities to its list.
Stockholm and Oslo saw the first deployments of 4G service by operator TeliaSonera late last year. But, as with the 3G services that preceded them, there is a catch. These services all fall under the 4G banner but these US and European networks use different protocols. Sprint and a number of operators in Asia have opted for services based on a mobile form of the Wimax standard that was originally developed to offer wireless broadband to homes and at least 250 are already in place. TeliaSonera and other large operators such as Verizon Wireless in the US and NTT DoCoMo in Japan have chosen the Long-Term Evolution (LTE) of the standard widely used for 3G today in Europe and Japan. As with 3G, there are strong technical similarities between LTE and Wimax – their differences often the result of their different lineages. Although the world ended up with three different 3G protocols, they were all based around the core technology of code-division multiple access (CDMA). CDMA2000, based largely on technology from Qualcomm, became the preferred standard for the US and Korea. In Europe and Japan, wideband-CDMA prevailed. TDS-CDMA was the last
14
eTech - ISSUE 4
The move from 3G to 4G is far smaller than the one from GSM to 3G that faced integrated circuit (IC) designers ten years ago
to launch, getting underway just ahead of the Beijing Olympics in 2008. One thing became very clear early on in the development of the 4G standards. The 4G networks would use some form of orthogonal frequency-division multiplexing (OFDM), the same basic technology as that used in WiFi wireless networks and ADSL for wired access to the internet. The situation is slightly simpler than with 3G as Qualcomm’s own successor to CDMA2000 did not enjoy success: operators picked either LTE or Wimax. There is good news for anyone who wants to implement LTE in industrial communications. In terms of the amount of die space that it takes up, the move from 3G to 4G is far smaller than the one from GSM to 3G that faced integrated circuit (IC) designers ten years ago. According to Professor Gerhard Fettweis of the Technical University of Dresden, whereas the 3G modem would use up a complete IC ten years ago, a modem that supports 2G, 3G and LTE implemented using today’s silicon technology does not need more than a quarter of a die. So, we are likely to see those functions combined with applications and graphics processors. That will not
”
only reduce the cost of 4G handsets, it means you can get the additional bandwidth and lower latency of LTE alongside high-speed CPUs that can be used for embedded processing. The result for designers of industrial systems is a set of wireless standards that support highspeed access to the internet at a lower cost than that of 3G when it first appeared. Analysts also expect the wireless dongle market to be much more important in the early development of 4G than they were for 3G, especially as the networks that underpin 4G are based on the Internet Protocol (IP) rather than being designed around the needs of voice communication. The design decisions behind the 4G standards help with applications such as security, realtime monitoring and control. Many network
protocols benefit from low latency as well as high bandwidth and LTE in particular was designed to reduce latency compared with 3G. This helps reduce the chances of time-outs and similar problems from disrupting communications, as well as helping applications such as videoconferencing where delay in sound and video can irritate the users. In applications such as telemedicine, LTE and Wimax bring higher peak bandwidths than their 3G predecessors, making it possible to have high-quality two-way video to allow doctors to make better diagnoses remotely.
Wimax can support downlink datarates approaching 50Mbit/s, with LTE promising 100Mbit/s, although the higher peak speed of LTE was only recently demonstrated by Telstra in Australia. But these are speeds that, for users closer to a basestation, compete well with ADSL minus the wires, making possible a host of new applications.
Get more online... Find out more on 4G, and add your voice on how the roll-out is going at www.designspark.com
eTech - ISSUE 4
15
Lane detector
zooms out the noise By Yifei Wang, Naim Dahnoun and Alin Achim Department of Electronic and Electrical Engineering, University of Bristol
Throughout the last two decades, a significant amount of research has been carried out in the area of lane detection to improve the safety of motor vehicles. These systems will prevent drivers from unwittingly moving out of their lane and into the path of other cars on the road. It is a difficult problem to solve as, even with clearly marked lanes, images captured by a camera contain a large number of extraneous features that can confuse the lane-detection algorithm. Feature extraction is a key part of lane detection: using image processing to work out which shapes in the frame form part of the actual lanes along which the vehicle is moving. By using the characteristics of the lanes and their shape information, a novel feature-extraction algorithm has been developed that can verify whether the features in a process belong to the lanes or are extraneous noise. Typically, while driving on a straight road with continuous lane markings, the positions of the lanes will not change significantly over time from the driver’s point of view. The algorithm takes advantage of the above phenomenon and tries to find the nonmoving features within the scene. In order to do this, a digital interpolationis is used.
By carefully selecting a region of the image and interpolating this region back to the original image size, the driver’s view can be simulated and the lanes on the interpolated and original images should overlap. The first task is to select the appropriate area for interpolation. On a flat, straight road, the vehicle will head towards the vanishing point where the left and right lanes meet on the horizon. A Sobel filter is used to generate lines for each clear edge in the image.The intersection of each line and the horizon’s ‘vanishing line’ is a possible position for the vanishing point of the lane. A voting system picks the point on the vanishing line to which most of the detected edges point. This technique works for flat, straight roads but few are like that. To extend this approach to curved lanes, Continued page 18>
16
eTech - ISSUE 4
eTech - ISSUE 4
17
Add USB connectivity to your application without completely redesigning the system
the image is split into a number of horizontal bands and perform vanishing point detection on each of the image bands.
As multiple vanishing points exist on segmented images each of the image bands has its own corresponding vanishing point and the results of edge detection on each section are compared separately. Image content above the vanishing line, which does not include useful information, is not processed in order to reduce the computational complexity. The system was implemented on a Texas Instruments TMSD6437 Digital Media Processor, based on the C64+ core which
18
eTech - ISSUE 4
can perform up to eight 8bit multiplyaccumulate (MAC) operations per clock cycle. The processor can be clocked at up to 700MHz. , although we run it at 600MHz, . Due to the high precision required in some algorithms a combination of 8 × 8bit and 4 × 16bit MACs, which the processor supports, have been used. This processor also provides a video subsystem. This provides a glueless interface to the standard video decoder and on-screen display. The combination of the video subsystem and the enhanced direct memory access (EDMA) that the processor supports simplifies considerably the data transfer from the camera to the processing buffer and from the output buffer to the display. If the EDMA and the central processing unit (CPU) are synchronised perfectly, the memory transfer overhead will be reduced to minimum. The captured frames (test videos are in NTSC format) are resized to 352 × 240 pixels to reduce the computation, using the onchip resizer hardware. The resizer is capable of generating output images from 1/4× to 4× the original image size in increments of 256/N where N is an integer between 64 and 1024.
comparison, in addition to the edge map from the original image. As the maximum zooming ratio is set to be 0.9 in normal cases, the selected zooming areas have almost the same size as the original image. Therefore a large amount of data needs to be transferred. However, a large portion of the image is repeated for each pair of the adjacent selected areas. Reusing the repeated areas will save the memory transfer significantly. In experiments, the initial gradient map was very noisy, containing a large number of unwanted features. The resizing and noise-removal algorithm successfully removes most of the unwanted feature but preserve the lane features, showing that the implementation results agree with the theory and are robust. The possibility of using the on-chip resizer to interpolate the zooming areas needs to be further investigated. But the complete system is running today in real-time at above 23 frames per second without the need to write code at the assembly level and just by managing the memory efficiently. Further optimisation could be achieved by identifying the slow parts of the code and optimise these parts using intrinsics, linear assembly or assembly.
The system was implemented can be separated into three main parts.The first is edge and vanishing-point detection, which takes 16% of the total computation power. Handling multiple vanishing points takes 2% of compute power.The last component of the process, digital interpolation and feature extraction, is the most processor hungry, taking 82% of the total computation power. As the iterative zooming process normally requires ten steps, ten different zooming areas need to be transferred into internal memory for interpolation and edge
Memory
The zooming and edge comparison process is carried out with different zooming ratios until most of the unwanted features are removed. Typically, the lanes will remain intact because, on a straight road, will remain approximately in the same position on the image no matter the scale factor. The other objects will disappear because they will not match up in all cases. Based on experiments, ten iterations are normally sufficient even under very severe conditions. During the edge comparison process, segmented lane markings will be shortened because of the change in length and position caused by the image scaling. Although they will stay on the same line after interpolation, the upper part of the line will be erased.
Analog
To extract the lane features and suppress noise from edges that do not belong to the lane markings, a logical-AND operation is applied to the original image edge map and to the edge map from the scaled, interpolated image on a pixel-by-pixel basis. If the interpolated edges overlap with the original image edges, these edges are preserved. More of the noise can be removed by rejecting edges that are clearly at the wrong angle to be a lane marking.
Digital Signal Controllers
The number of edges belonging to the lane boundaries found by the Sobel filter will decrease with distance, so the vanishing point of the lowest, and nearest, image band is detected first. The vanishing points on the upper bands are detected based on the vanishing-point position of the lower bands to reduce the detection error and the amount of processing needed. Detection accuracy is helped by tracking the position of the vanishing point frame by frame on the basis that the position of the vanishing point will not change dramatically.
Microcontrollers
Does your product design require a USB Connectivity upgrade?
< Continued from page 17
Microchip offers design engineers a complete, out-of-the-box solution that makes it easy to add USB connectivity to existing systems. The MCP2200EV-VCP USB-to-RS232 Demo Board is a low-cost evaluation tool which is supported with software libraries and a PC based configuration tool, the board removes the burden of thoroughly understanding the USB protocol from system designers, which simplifies the addition of customizable USB functionality to existing designs.
ORDER YOUR MCP2200EV-VCP DEMO BOARD FROM RS TODAY!
The Board serves as a complete USB-to-RS232 converter solution (dongle) and provides USB-to-GPIO capability, enabling designers to manipulate the on-chip I/O from the included PC software, so that they can program and test different functional configurations. The whole solution is designed to shorten time-to-market for a variety of applications in addition to legacy RS-232 applications.
Features: • • • • •
MCP2200EV-VCP : RS Stock No 699-0448 : ~ £16.00 MCP2200-I/MQ : RS Stock No 698-8990 : £1.54 MCP2200-I/SO : RS Stock No 698-8993 : £1.42 MCP2200-I/SS : RS Stock No 698-8997 : £1.42
Powered via USB Test points for all GPIO pins RS232 device and 9-pin D-sub connector for connecting to RS232 applications Tx and Rx LEDs for indicating USB to UART traffic (when enabled) Software for configuring special features of the device
Intelligent Electronics start with Microchip See our full range of TI digital media processors available from stock at rswww.com/ti
rswww.com/microchip The Microchip name and logo, the Microchip logo and PIC are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. All other trademarks mentioned herein are property of their respective companies. © 2010, Microchip Technology Incorporated. All Rights Reserved. ME276Eng/08.10D
DESIGN REVIEW
DESIGN REVIEW
Using the
ARM mbed in the cloud By Dr William Marshall, RS Components
The launch of the mbed development system for ARM-based microcontrollers represents a revolution in the way computer software and firmware is developed. The expensive business of buying software development tools such as IDEs and compilers is eliminated by using internet-based resources. This article describes my first experience with this new way of working: the aim being to find out just how ‘rapidly’ I could prototype a simple mobile robot collision avoidance system using the NXP LPC1768-based mbed module and a commercial ultrasonic sonar unit. The mbed kit hardware On opening the box you will find: the tiny mbed module itself, a USB cable, a credit card-sized aide-memoire showing the module pin functions and a single sheet of ‘Getting Started’ instructions. Oh, and a useful mbed sticker. There is no CD with megabytes of software to be installed on your PC, no small print informing you that you will have to purchase the full versions of the development tools if you want to create anything larger than a program to blink an LED. Instead, you are told to connect the module to a PC with Internet
access using the supplied USB cable and then navigate to the mbed web site. The module is USB-powered and needs no separate supply. Getting on-line As soon as you make the USB connection to your PC, drivers will be installed and the mbed module will appear as a new drive in Windows Explorer. The drive contains only one file at this point: mbed.htm. Double clicking on this file will open your web browser at the mbed home page where selecting ‘Signup’ will take you to the registration screen. Once your module is registered you will have access to the Compiler. This is a social networking site for engineers, so you have your own home page, a ‘notebook’ or blog where you can jot down thoughts and ideas on a project and file space for your programs. I also like the way I can work on a project anywhere there’s an
internet connection: drop the breadboard in my briefcase with a laptop and I’m no longer tied to the lab! Getting the hardware together My test project involved interfacing an SRF08 ultrasonic rangefinder unit and a simple dc motor to the mbed module. The SRF08 has an I2C bus so linking it to one of the two I2C ports available just involved a few wire links and a couple of pull-up resistors. The mbed module has a +5V output (from the USB port) and this powers the rangefinder. The motor requires more current than the mbed can supply so it will require a separate PSU, but this could be a battery pack to keep things portable. The popular L293D H-bridge driver chip is used to drive the motor from one of the six available PWMout lines. Programming Before creating some code, I realized debugging would be a whole lot easier if program output data could be displayed on the PC using a serial terminal emulator such as Windows Hyperterminal. A Serial Port driver must be installed on the PC first and is thoughtfully provided in the ‘Handbook’ section. This allows the C functions printf and scanf to be used in a program. Click on ‘Compiler’ and a new window opens revealing an IDE-type screen, but much simpler and with no de-bugging features. Select ‘New’, type in a program name and you’re ready to add some program lines. The language is C with the object classes of C++. The first line of a C program is normally #include “stdio.h” which brings in the library of standard functions, but in this case we use #include “mbed.h” for the same purpose. The library contains the necessary drivers for all the port pins including I2C, PWM and DigitalOut.
20
eTech - ISSUE 4
// mbed test program using I2C and PWMout: WGM 6/2010 // Uses SRF08 Ultrasonic Range Finder #include “mbed.h” I2C sonar(p9, p10); Serial pc(USBTX, USBRX); PwmOut motor(p21); const int addr = 0xE0; char cmd[2]; char echo[2];
// // // //
Define SDA, SCL pins Define Tx, Rx for PC Define PWM pin I2C device address for SRF08
int main() { // Set up SRF08 max range and receiver sensitivity over I2C bus cmd[0] = 0x02; // Range register cmd[1] = 0x1C; // Set max range about 100cm sonar.write(addr, cmd, 2); cmd[0] = 0x01; // Receiver gain register cmd[1] = 0x1B; // Set receiver gain sonar.write(addr, cmd, 2); // Set up PWM frequency motor.period(0.01);
// Set PWM frequency = 100Hz
while (1) { // Get range data from SRF08 // Send Tx burst command over I2C bus cmd[0] = 0x00; cmd[1] = 0x51; sonar.write(addr, cmd, 2); wait(0.07); // Read back range over I2C bus cmd[0] = 0x02; sonar.write(addr, cmd, 1, 1); sonar.read(addr, echo, 2);
// Command register // Ranging results in cm // Send ranging burst // Wait for return echo // Address of first echo // Send address of first echo // read two-byte echo result
// Generate PWM mark/space ratio from range data float range = (echo[0]<<8)+echo[1]; range = range/100; // Turn range into PWM ratio motor.write(range); // Update PWM pulse-width pc.printf(“range = %0.2f\n”, range);// Send PWM ratio to PC display wait(0.1); }
}
Fig 1. Sonar program source code
The program listing shown in Fig 1 is for my sonar system. When you have created your source code, select Save to keep it in your mbed folder. Now select Compile and watch for the message ‘Success!’ or more likely, the list of errors. When you have cleared all the bugs and there are no more errors, a message inviting you to save the binary file will appear. This triggers the download to the mbed module. Hit the reset button and your program will run. The development cycle is really that simple: a few hours assembling the hardware and producing the initial program code. That includes initial familiarization of course. Test Program The sample program illustrates how device drivers are taken from the web Handbook and just pasted in where required. The program reads the range to an obstacle up to a
maximum of 100cm from the SRF08 module via an I2C serial bus link. A PWM signal drives the motor at full speed at maximum range, progressively reducing it as the obstacle gets nearer. The first version of the program was rather longer than necessary because of a bug in one of the higher-level I2C drivers. I used the forum to discuss the problem and eventually the bug was traced and modifications included in the following release of the mbed library header file. Interactive development This is development ‘in the cloud’: fast access to experts in the field and interaction with other engineers and designers working on similar problems. It would be easy to get carried away with this concept of open development, but it will not suit everyone working in a commercial environment. Obviously there is the question of security for your brilliant new ideas, and the practical limitations of the development
Fig 2. mbed pin functions
software and hardware. You do not have access to debugging features such as breakpoints and single-step operation for example. For checking out design ideas involving small amounts of program code mbed is ideal, making it perfect for students and small companies unable to afford the large investment necessary in full development systems. RS Embedded Development Platform (EDP) RS Components have released an adapter module (part no.703-9235) for mbed which allows this type of internet-based development to be applied to an EDP system. A dedicated processor module for the LPC1768 has also been released (part no.703-9229) which can then replace the mbed unit when a more sophisticated development environment is required. These will be covered in a future Design Review. Additional material The circuit diagram for the collision avoidance hardware together with a file version of the program source code are downloadable from the eTech website. The LPC1768 mbed module used in this article is available from RS Components: part no. 703-9238.
Get more online... Download the sonar program source code and connect wiring diagram from Design Review at www.rs-components.com/etech eTech - ISSUE 4
21
MARKET TRENDS
Shipments of Cell Phone Motion Sensors to Rise Fivefold by 2014
Not Your Average Test Bench Now it’s easier than ever to debug those complex designs
Accelerometers, compasses, gyroscopes, pressure sensors penetrate smart phone market. Global shipments of motion sensors for cell phones are expected to quintuple by 2014 as smart phones and their operating systems increasingly support motion command and navigation applications that require these parts, according to iSuppli Corp.
Accelerometers speed ahead In 2014, accelerometers will account for 44 percent of total motion sensor revenue for cell phones. By that time, 65 percent of all phones will incorporate accelerometers, up from 2 percent in 2007 and 28 percent in 2009.
Shipments of cell phone motion sensors – i.e., accelerometers, compasses, gyroscopes and pressure sensors – will rise to 2.2 billion units in 2014, up from 435.9million in 2009. Revenue will amount to slightly more than $1 billion in 2014, up from $316 million in 2009.
Falling prices for 3-axis parts will promote the growth of accelerometer sales. Prices for low-end, 6-bit 3-axis accelerometers are set to decline to 34 cents by 2014, down from 90 cents in 2008. The share of higher-end 12-to-14 bit accelerometers will increase because these are essential for more sophisticated hand gesture recognition and navigation applications.
Motion sensors such as accelerometers and compasses already play a key role in the functionality of smart phones like the iPhone or Google phones. Accelerometers detect when a phone with a large touch screen has been turned on it’s side, allowing the devise to switch from portrait to landscape view. They also play a key role in gaming and navigation functions, and increasingly are used in augmented reality and context-awareness applications. Furthermore, the expanding presence of accelerometers in cell phones can be seen in the hundreds of Independent Design Houses (IDHs) in China adopting motion sensors in 2009. Nearly 20 percent of the global shipments of accelerometers for cell phones went to China in 2009, iSuppli estimates, with the vast majority used in the Chinese gray handset market.
Compasses point north Shipments of compasses for cell phones exploded in the second half of 2009. In 2009, 19 percent of GPS phones used a compass, up from 4 percent in 2008. Compasses support navigation, enabling auto rotation of maps to match the direction a user is facing. Augmented reality applications that combine the compass, GPS signal and camera are also a big driver in Andriod phones and in the iPhone 3Gs. These attributes are so compelling to consumers that competing smart phone platforms, including Google’s Andriod and Microsoft’s Mobile Windows 7, are promoting or even mandating support for these features. This will cause shipments of compasses for mobile phones to boom during the coming years.
Gyroscopes spin up Mobile handset makers showed little interest in gyroscopes until early 2009. That changed, however, in mid 2009 following the success of the Nintendo Wii Motion Plus and the advent of a cascade of new gyroscopes with 2 and 3 axes from IvenSense and STMicroelectronics. Gyroscopes were expected to enter the first smart phones this summer. The main applications in 2010 and 2011 will comprise a user interface utilizing a gyroscope in combination with an accelerometer, followed by image stabilization and dead-reckoning for in-vehicle navigation. From 2012, gyroscopes will start to be used for indoor navigation combination with an accelerometer, compass and pressure sensor for floor accuracy. By 2014, the market for gyroscopes in cell phones is expected to amount to $190 million. Semi opportunity With the anticipated upsurge of motion sensor shipments in the years to come, additional opportunities along the supply chain will be created for semiconductor companies, affording participation to the manufacturers of processors, microcontrollers and navigation chipsets, iSuppli believes. At present, new architectures are being explored that can offload the application processor, optimize power consumption at the system level and improve response time. By Jérémie Bouchaud the director and principal analyst of MEMs at iSuppli Corp.
Debug is hard enough. Don’t let your test instruments get in the way. Our test bench offers the same ease-of-use you’ve come to expect from our oscilloscopes. From dedicated buttons for common functions to USB ports for saving data. To simplify your most complicated tasks, you can connect your test bench with the included copy of LabVIEW SignalExpress™ from National Instruments. Control your Tektronix instruments right from your PC. Automate measurements and analyze data across multiple instruments. Capture and save results. Create reports. Take your test bench from average to extraordinary. Basic Oscilloscopes 40 MHz to 500 MHz bandwidth
■
5.5 digit and 6.5 digit resolution
■
Up to 25 automatic measurements
■
Dual display
■
Battery operation available*
■
Statistics, histogram and trending modes
*Depends on model.
Bench Oscilloscopes ■
100 MHz to 200 MHz bandwidth
■
Up to 4 analog and 16 digital channels
■
Parallel and serial bus analysis
■
Wave Inspector® for fast navigation of data
Shipments of motion Sensors in Mobile Handsets
Millions of Units
Arbitrary/Function Generators
Get the Latest MEMS and Sensors Research at www.isuppli.com/MEMS or by contacting iSuppli via info@ isuppli.com. Discrete motion sensors
22
eTech - ISSUE 4
Motion sensors as part of multi-sensor chipset
Copyright 2010 iSuppli Corporation.
Digital Multimeters NEW!
■
■
Up to 240 MHz bandwidth
■
One or two channel models
■
12 standard waveforms, including arbitrary
Power Supplies NEW! ■
Up to 72 V output range
■
Up to 0.5 mV and 0.1 mA resolution
Timer/Counter/Analysers NEW! ■
12 Digit/s frequency resolution
■
50ps time resolution
■
Measurement statistics, histogram & trend plots
Industry Leading 3-Year Warranty included with all Tektronix bench instruments.
rswww.com/tektronix © 2009 Tektronix, Inc. All rights reserved. Tektronix products are covered by U.S. and foreign patents, issued and pending. TEKTRONIX and the Tektronix logo are registered trademarks and LabVIEW SignalExpress is a trademark of National Instruments.
A world of
switching capabilities By Jerry Abraham Central Product Manager, RS Components
More than ever, designers are turning their attention to the human-machine interface, spurred by increasing variety of designs and technologies available from switch manufacturers. New tactile switches and keypads are making their mark across medical, industrial, security, defence, telecom, computer, transport and consumer electronics.
As well as variety, manufacturers are meeting the challenges of cost reduction, space-saving, regulation, reliability and product lifetime. Making tact switches smaller Compact size and quality products are the driving forces behind APEM’s MEC micro miniature tactile switches, which offer designers substantial savings in board space and surface mount options for higher-volume automated assembly. MULTIMEC switches are IP67 sealed and suitable up to 10 million operation. The MULTIMEC family offers small
24
eTech - ISSUE 4
footprints and variable heights from the board to top of the switch. The switches can be reflow soldered and are available in tape-andreel packaging where required. Large switches for the less able user At the opposite end of the size spectrum, regulations and ergonomics set the background to APEM‘s new LPI series, which provides the largest actuator and lowest behind-panel depth in the portfolio. The LPI has been developed based on a modular concept, thereby providing large number of
permutations and combinations to fit the exact needs of the customer. These tactile switches are available in two output versions, for front or rear mounting: a 5A combined separated NO/NC version and a 0.5A NO version. The low behind-panel depth allows installation in environments where space is critical. Because of its large actuator, this series is ideal for all applications where the pushbutton needs to be located quickly. Complying with the requirements of the EN81-70 standard (from
Disability Discrimination Act), it allows disabled persons to access lifts and buildings more easily.
benefits of simpler customisation, high security and reliability and ease of cleaning.
Membrane switches innovation OEMs looking for more complex humanmachine interfaces are increasingly turning to membrane switch panels in order to embellish and protect their endproducts. Medical devices, food processing machinery and outdoor equipment such as kiosks all reap the
Built using a sandwich of polyester and adhesive, the APEM membrane switches are simple to mount and are directly connected to the electronic equipment by a flexible tail termination. Tactile feedback can be provided through the use of either a metal snap dome under the flexible surface, or by embossing the top layer itself. APEM uses a wide range of materials and adhesives including versions with Microban® antimicrobial protection for medical equipment. The latest twist to switch panels’ range of options comes in the form of electroluminescent backlighting. Designed as an integral layer behind the front face graphic, the electroluminescent film allows membrane switch panels to be used in darkened areas or for night time use, making them ideal for many automotive
applications, navigation, marine and medical equipment. Transparent ink can be printed over the EL to allow any colour illumination to be produced. With innovations like these, it is no wonder that there has been an explosion in the range of options available to designers.
RS has added over 800 new lines from APEM in the last six months. See our full range available direct-fromstock at rswww.com/apem eTech - ISSUE 4
25
EDP UPDATE
EDP Goes Wireless With the demand for wireless connectivity growing relentlessly, EDP has been extended to support fast development of RFID or GSM/GPRS based applications. With the introduction of two new wireless modules, engineering teams using EDP and the mbed module can quickly add RFID, GSM/GPRS or both technologies to their next application. Both wireless technologies are now fully supported by EDP, including an extension to the software development environment to include wireless telemetry, and a production-ready software library of wireless modules developed by ARM to target the new RFID and GSM/GPRS modules. EDP The RS Embedded Development Platform (EDP) offers engineers access to leading edge technologies in a configurable and flexible format, allowing rapid R&D using production-ready software and proven reference designs. One of the great strengths of EDP is its close alliance with ARM’s mbed; the processor module that gives engineering teams easy access to the Cortex-M3 32bit embedded microcontroller core, through NXP’s LPC1768. These modules are fully supported by EDP, including the software library created to support the growing number of EDP modules available. The alliance with ARM has yielded two technology reference designs utilising the new wireless modules.
Our online quote tool is so quick it will give you a slice of your day back
The new wireless modules The new EDP wireless modules were developed by RF Solutions and are exclusively available from RS Components. The RFID modules connect to EDP through a generic interface, which allows any of the MicroRWD (HITAG) RFID modules designed by specialist supplier IB Technologies to plug in to EDP. IB Technologies offers a range of production-ready modules and with the support of EDP, engineers can now easily adopt what is rapidly becoming one of the most widely applied wireless technologies in the industry. The GSM/GPRS modules also plug into EDP via a generic interface and are supplied with a full Bill-of-Materials and schematics, helping customers implement the same solution in production volumes. The modules are based on the Huawei GTM900 modules. This includes tri-band operation at 800, 900 and 1800MHz, packet data services of GPRS Class 10, a maximum bandwidth of 115.2kbit/s and support for speech encoding. With the addition of wireless, EDP now brings together an even wider range of leading-edge technologies, allowing the combination of complementary solutions in a single development environment that greatly accelerates development cycles and simplifies system design.
26
eTech - ISSUE 4
Get more online... Go to www.designspark.com/theme/edp to download software libraries and schematics for the ARM project. Stay up to date with the latest additions to the RS EDP portfolio at rswww.com/edp
Online Quotes rswww.com/tips
R-78 switching regulators. The number one for over five years The R-78xx-0.5 series, which is in a sense the “mother” of all of our R-78 switching regulators, offers 1.5-15 VDC output voltage with a maximum output current of 500 mA and 32 VDC input voltage. The unit’s SIP-3 casing measures only 11. 5 x 10 x 8 mm and provides up to 7.5 watts of power output. The regulators are also available in an SMD version.The R-78AAxx-0.5SMD and R-78AAxx-1.0SMD series are RoHS 6/6-compliant and thus 100% lead-free.
The key features of the R-78 series at a glance: ✔ ✔ ✔ ✔ ✔
Up to 97 percent efficiency Full short circuit protection Pin-compatible with LM78 line regulators Additional input voltage range (4.75V-32V) No heatsink necessary
R-78 series. R-78 switching regulators are often used for very low power microprocessor circuits.
DESIGN TIPS
IN ASSOCIATION WITH
BOOSTER FOR AUDIO SIGNALS Cranks up bass & treble By Markus Aebi (Switzerland)
For more info visit: rswww.com/recom
Dull and washed-out sound? With modern recording technologies this is unlikely to happen. There are nevertheless situations where a fuller sound would do no harm (live bands, for example, but cheap headphones could also benefit). A small amount of ‘effect‘ could make the sound experience just ‘perfect‘.
The up to 97 percent efficiency of the R-78 switching regulator series obviates the need for a heat sink
Weak bass and dull treble frequencies are things of the past with this circuit. The ingenious principle of the project described here makes the reproduction more delicate, fuller and subjectively louder. The circuit was originally intended to be built into a mixing desk (immediately before the Master Fader), but works just as well as a standalone device when the input and output voltages are adjusted appropriately (about 1.5 Vp/0 dB at the first op amp).
UTS Hi seal
Dynamic IP68/IP69K Waterproof connectors in mated and unmated condition
Protection of electronics inside the equipment/boxes in case of maintenance, unmated conditions or cable damage
Sealed unmated
f oo -pr ing n sio us rro ic ho o C ast Pl
■ Operational safety - ESD · plastic shells ■ Rapid and secure locking system · quick disconnect ■ Suitable for overmoulding · sealed insulator and contacts ■ Available : · 4 shell sizes, · 16 different layouts · multiple polarization options. · standard connectors supplied with preassembled solder and PCB contacts. ■ UV resistant · suitable for outdoor use
SOURIAU your Key Success Partner www.souriau-industrial.com
RoHS
Compliant
The principle The high and low frequencies are processed independently of each other. The left and right channels are identical, with the exception of the part of the circuit controlling the amplification of the low frequencies, which is used for both channels and therefore does not need to be implemented twice (see Figure 1). After the high-pass filter with C4 (C15 for the right channel) the high frequencies are amplified ‘quick and dirty’ with the circuitry around T1 (T2). The diode pair D1, D2 (D3, D4) generates higher harmonics which are added to the original signal with potentiometer P1A (P1B). This makes it sound ‘fresher’. The low frequencies are separated from the original signal with the network around IC1B (IC2B) Continued page 30> eTech - ISSUE 4
29
DESIGN TIPS
DESIGN TIPS low-pass filter (and also has a variable phase shift with respect to the original signal, which results in a subjective amplification of the low frequencies). The values of the RC pair affect the tuning of the filter. The selected resistor of 33 kΩ in combination with a capacitor of 22 nF gives optimum tuning.
+15V 3k9
R6
T1
D1
1k 3n9
P1A
IC4A
11 2
8 C11 22n
100n
8
C26
4
C28
100n
4
C30
+15V
C12 220n
2
100k
R
3 R19
IC2A
1
R22 1k
C15 3n9
1n
C16 10p
T2
BC550C
220n
1N4148
-15V
C17
R23 390k
IC3 = NE5532
C18
D4
1N4148 D3
470p R25
R26
1N4148 P1B
R20
5
C14
4k7
47k
7
R28 100R
10u 50V
R
39k R34
9 C22 22n
R35 4k7
2k2
4k7 log.
10n
C21
1u
R33 10k
C13
R32
7
C20
13
P2B
IC3B
220p
15
16
IC2B
6
R27
14 R31
12 10
6
R30 1k5
R29
92k
5
C19
IC4B
47n
33k
92k
4k7 log.
R21
IC4 = LM13700
R36
-15V
Construction When assembling the PCB you follow the traditional procedure: first the ‘small’ parts such as resistors and diodes, then the ‘bigger’ parts such as capacitors and transistors. We used sockets for the ICs sothat swapping the op amps for a different sound is very easy. The construction is not all that difficult because no SMD components are used.
080094 - 11
Figure 1. The schematic may strike as quite sizeable, but the dimensions of the PCB are very reasonable.
< Continued from page 29 and subsequently passed on to the current-controlled operational transconductance amplifier (OTA), which is configured as a VCA here (Voltage Controlled Amplifier, IC4A and IC4B respectively). The ‘Dynabass’ potentiometer P2A (P2B) determines how much of the original signal is processed. RC network R16/C11 acts as a variable
+3
In our prototype we chose to use headers and sockets for the connections to the two double potentiometers. These are mentioned in the parts list. It is, of course, also possible to omit those headers and connect the potentiometers directly to the board using short wires. The double-sided PCB has been made as compact as possible (88 × 69 mm) and has not been designed with a specific enclosure in mind (see Figure 2). The PCB layout can be downloaded from the eTech website. Measurements The two graphs summarise how the circuit influences the signal. The graph in Figure 3 shows the amplitude characteristic of the low-pass
Elektor
-3
+10
-6
+0
5
-9 -12
-5
2
-15
d B -18
-10
THD + N %
1
V -21 -24 -27 -30 -33 -36 -39 100
200
500
Hz
1k
2k
5k
10k
20k
080094 - 12
-15
0.5
-20
0.2 0.1
-25
0.05
-30
0.02
-35
0.01 -40
-35
-30
-25
-20
-15
dBV
Figure 3. This clearly shows the frequency range of the low frequency part of the circuit.
30
eTech - ISSUE 4
Capacitors C1,C12,C23 = 220nF, lead pitch 5 or 7.5mm C2,C13 = 10nF, lead pitch 5 or 7.5mm C3,C14 = 47nF, lead pitch 5 or 7.5mm C4,C15 = 3.9nF, lead pitch 5 or 7.5mm C5,C16 = 10pF, ceramic, lead pitch 5mm C6,C17 = 1nF, lead pitch 5 or 7.5 mm C7,C18 = 470pF, ceramic, lead pitch 5mm C8,C19 = 220pF ceramic, lead pitch 5mm C9,C20 = 1µF, lead pitch 5 or 7.5mm C10,C21 = 10µF 50V, radial, bipolar, lead pitch 2.5mm, diam. 8.5mm max. C11,C22 = 22nF, lead pitch 5 or 7.5mm C24 = 10µF 63V, radial, lead pitch 2.5mm, diam. 6.3mm max. C25–C30 = 100nF, lead pitch 5 or 7.5mm C31,C32 = 100µF 25V, radial, lead pitch 2.5mm, diam. 8.5 mm max.
Semiconductors D1–D6 = 1N4148 D7 = low current LED, red, 3mm T1,T2 = BC550C T3 = BC547B IC1,IC2,IC3 = NE5532, 8-DIP case IC4 = LM13700 16-dip
RS Stock No. 652-7343 228-5916A 545-2254 454-2232 810-188 533-9656 / 533-9656a
Miscellaneous RS Stock No. 11 pcs PCB solder pin 434-138 4 pcs 3-way pinheader (P1,P2) 668-9520 4 pcs 3-pway socket 495-8537 PCB, # 080094-1 Go to Design Tips www.rs-components.com/etech
RS Stock No. 622-4218 312-1431 622-4555 622-455 / 312-1661 538-1360 622-4268 683-2112 683-2109 483-3933 440-6547 334-164 365-4240 652-9995 684-1942 Figure 2. The components are quite close together so that the circuit will fit on a compact PCB.
filter. This shows that the low-frequency part of the circuit operates below about 100 Hz. At the high-frequency end the circuit operates from around 5 kHz, based on the clipping of T1 (T2).
+5
10
50
RS Stock No. 151-303 151-117 157-446 683-3594 151-016 150-928 151-325 683-2705 148-893 151-094 151-000 151-088 148-893 683-5518 387-896
Elektor 30 20
+0
-42 20
Resistors R1,R19 = 100kΩ R2,R3,R20,R21 = 92kΩ R4,R22 = 1kΩ R5,R23 = 390kΩ R6,R24 = 3.9kΩ R7,R8,R15,R18,R25,R26,R33,R36,R39 = 10kΩ R9,R27 = 39kΩ R10,R28 = 100Ω R11,R29 = 47kΩ R12,R30 = 1.5kΩ R13,R17,R31,R35,R38 = 4.7kΩ R14,R32 = 2.2kΩ R16,R34 = 33kΩ R37 = 470Ω P1,P2 = 4.7kΩ logarithmic, stereo
10k
-15V
10k
-15V
IC2 = NE5532
C23 D5
BC547B
R24
100n
100n
10u 63V
When both potentiometers are set to their minimum positions the signal passes through unchanged. An external symmetrical power supply of ±15 V completes the story. The current consumption at this voltage is about 40 mA for the positive supply rail and 35 mA for the negative supply rail. Each IC is provided with decoupling capacitors and the PCB is fitted with additional 100 µF buffer electrolytics.
IC1 = NE5532
T3
1N4148
C24
100n
R18
D7
R37 470R
3k9
100u 25V
C29 8
IC3
IC2
4
D6
+15V
R38
-15V
10k 100n
R17
The control current of the VCA, which determines the gain of this IC, is generated with the circuit around T3. This circuit works as a kind of limiter circuit (quasi limiter function) and shows via LED D7 how much ‘control’ is applied. The processed signal is added to the signal immediately after the ‘Harmonics’-potentiometer (P1A and P1B respectively).
10k
R16
4k7
+15V
4k7
1
5 7
6 2k2 C27
C25 8
IC1 C32
R15
-15V
R39
C31
L
C9
+15V
100u 25V
R10 100R
10u 50V
1u
R14
4k7 log.
10n
C10
1
R9
3
4
P2A
C2
IC3A
39k
R13
2
10k
47k
7
IC1B
1k5
92k
6
R12
R11
4k7
47n
5
C8 220p
10k
92k
C3
3
4k7 log.
+15V
R3
0
R8
1N4148
BC550C
R2
+15V
470p R7
-10
-5
+0
+5
+10
-40
080094 - 13
Figure 4. The gain and distortion of the low frequencies depends on the input voltage.
dBV
1
IC1A
100k
2
C4
D2
1N4148
10k
R1
R4
C7
C6 1n
33k
220n
L
3
C5 10p
10k
R5 390k C1
Component List
probably only use flawless signal sources. For everyone else who would like their sound to be fresher and livelier this booster circuit is a good alternative to an equalizer.
The second curve (Figure 4) shows the ratio between the amplitudes of the input and output signals of the VCA (green curve), measured at pin 9 of IC4. It shows that the curve is linear up to about –10 dB, after which compression occurs. The effect of this is that the low frequencies are accentuated a bit more and the entire sound sounds fuller. The same graph also shows the distortion of the output signal at 60 Hz and 1 V input voltage, measured at pin 9 of IC4 (blue). The –10 dB value is also represented in this curve, with the difference that the distortion increases exponentially from that point onwards (this makes sense because the signal is compressed above that value). This is naturally not a circuit of particular interest for audiophiles. But they
Get more online... Download PCB artwork from Design Tips at www.rs-components.com/etech
eTech - ISSUE 4
31
Electronics Extras
Electronics Extras
ANTI-STATIC GLOVES For assembly / inspection of sensitive electronic components n A low linting white antistatic glove with PU palm coating giving a tight fitting for maximum dexterity and tactility. Antistatic to EN1149 part 1:1995, Class 1000 clean room compatible. Supplied as a pair, packed for cleanliness. Online search term: 622-6955
PCB INSPECTION MAGNIFIER 8x magnifying eye glass with acrylic lens for PCB inspection n Has integral metric/imperial graticule for direct measurement. The base cover incorporates 35mm film negative and 35mm slide viewing apertures. Online search term: 544-083
NYLON THREADED SPACERS A large range of metric insulated spacers in a variety of types. n M3 to M6 spacers in varying lengths in either male to female or female to female types. Inserts can be either nylon, brass or nickel plated brass. Online search term: Nylon threaded spacers
MAINS EXTERNAL POWER SUPPLIES A wide range of products brought to you by RS n Whether you need AC or DC output, UK or European plugs RS has a range of power supplies to suit your needs from 1.5V to 24V Online search term: RS linear external power supplies
STYLISH ELECTRONICS ENCLOSURES TEKTRONIX BENCH MULTIMETER With 5.5 digit resolution, up to 1μV or 1nA n Measures Volts, Ohms, current, and frequency. Includes diode and continuity testing. With 2×4 Ohms 4-wire measurement technique, dedicated DC leakage current measurements, six dedicated buttons for fast access to instrument setups, limit compare mode for Pass/Fail testing. Connects to test systems via RS-232 or USB via LABCOAT supplied interface adapter cable. Includes National Instrument’s LabVIEW Designed with comfort SignalExpress™ TE Limited Edition and practicality in mind. software. With 3-year warranty. Online search term: 697-4196 n Generously cut with a front zip, knitted cuffs and an internal pocket, it is ideal for use on production lines and laboratories. The fabric is a multi-layer, breathable material which has anti-static properties to conform with EN1149-1, and is fire retardant to EN533 Index 1. Online search term: Candour lab coat
n A new range of eye-catching console format aluminium enclosures available in a choice of sizes with either silver of graphite grey powder coating and providing IP65 sealing. Online search term: Alustyle
LOW PROFILE EMERGENCY STOP SWITCHES n EAO 84 series illuminated and nonilluminated 22.5mm hole mountable emergency stops switches. Low depth contact block construction with 300mm ribbon cable termination. Ideal for use in portable equipment or anywhere space is restricted. Online search term: EAO 84 e-stop
ESD SCREWDRIVER AND BIT SET SAFESHIELD CARDBOARD BOX n This handy size cardboard box has foam inserts to help protect whatever you want to transport. Online search term: 443-9929
32
eTech - ISSUE 4
n 16-piece set for use in sensitive electronic applications. Set contains telescopic handle with flat, pozidrive, Torx and hexagon bits. Online search term: 706-4815
See more online - Over 5,000 new products are added at rswww.com/electronics every month
eTech - ISSUE 4
33
DESIGN REVIEW
DESIGN REVIEW
Embedded Systems
Run, Sleep, Deep Sleep…
NEC Electronics
Microchipxx
Texas Instruments
Run/Dynamic/Normal Mode
Run/Dynamic Mode
Active Mode
Halt Mode (Main) all peripherals on
Sleep with WDT
Halt Mode (subclock) some peripherals on
Sleep with RTC or RTCC
LPM3 LFXT1 Standby Mode
Stop Modex
Sleep Mode
LPM4 RAM Retention
n/a
Deep Sleep with RTCCxxxx
LPM5 Shutdown Mode
n/a
Deep Sleep with RTCC
n/a
By Siegfried W Best Editorial Team, Elektronik Industrie
xxx
LPM3 VLO Standby Mode
x
Dependent on the subclock, partial peripherals on (LCD/RTC etc., WDT with own frequency, RAM data retention) Microchip also has a Doze Mode in which the CPU frequency is lower than the peripheral frequency xxx LPM = Low Power Mode xxxx = xx
These days, it is not only battery-powered devices like games consoles, wireless weather stations, blood pressure gauges, smoke alarms, etc. that require economical µCs. Examples of other application areas that demand low power consumption are smart metering devices that measure usage of utilities, such as water, gas and electricity.
Table 1: An attempt to compare the different definitions for energy-saving modes from manufacturers NEC Electronics, Microchip and TI
Run/Dynamic/ Normal Mode
Sleep Modexx
Sleep Modexxx
Deep Sleep
Wake-up Time
Energy Micro
EMF32
195µA
900nA
600nA
20nA
2µs
NEC Electronics
µPD78Kx2-L
220µA
580nA
730nA
300nA
2 ... 3µs
NEC Electronics
µPD78Kx3-L
190µA
700nA
900nA
330nA
Microchip
PIC16F193X
150µA
440nA
540nA
80nA
1µs
Microchip
PIC24F16KA102
195µA
400nA
500nA
28nA
1µs
TI
MSP430x1xx
220µA
500nA
900nA
100nA
1µs
x
xxxx
23.3 ... 30.7µs
Ub 3V, 1MHz; xx with BOD+WDT; xxx with BOD, WDT+RTC; xxxx until CPU starts, periphery is already on
Table 2: Comparison of the significant low power measurements for economical microcontrollers from the manufacturers NEC Electronics, Microchip and TI
‘Low power’ describes an application area or market segment where the microcontroller is only active for a fraction of its lifetime, with a duty cycle that can often be as low as 10%. According to an EU directive, even in a parked car the combined control devices may only draw a maximum of l50 µA from the battery while the engine isn’t running. Additional regulations (EU Regulation 1275/2008 of 17 December 2008 to implement Directive 2005/32/EG) mean that from 7 January 2010, power supply plugs and any household devices (except devices with a digital display) may now only draw up to 1W in standby mode. From
34
eTech - ISSUE 4
2013, this will be further lowered to 0.5W.
Low Power Parameters/Operating Modes It wasn’t only Energy Micro’s announcement of Gecko that kicked off a discussion about the different low-power operating modes, but other manufacturers of economical microprocessors, especially NXP and TI, seem to have woken up since Gecko’s arrival. Looking through the data sheets from different vendors, the reader is assaulted with a multitude of terms for power consumption that are very difficult to compare with each other. For example, you would find values for power consumption in Run Mode, in Standby, in Sleep Mode, in Deep Sleep Mode, in Stop Mode, in Shut Off Mode, in Standby Mode, in Extended Standby Mode, in Idle Mode, in Power Down, in Power Save, in RTC Mode, in RAM Retention Mode, etc. Comparisons are difficult because different manufacturers often mean the same thing but they call it by a different name (see Table 1).
All manufacturers of economical µCs attempt to keep the current leakage from the semiconductor processes, due to temperature and operating voltage, as low as possible because this has a significant effect on power consumption in the energy-saving modes. The problem is, however, that the trend towards ever narrower structures with higher clock frequencies and smaller chip areas leads to increased current leakage.
In Run or Active Mode, power consumption rises with the clock frequency, which is kept as low as possible to minimise consumption. However, the clock frequency is also influenced by other factors such as the associated peripherals, the architecture and the instruction set. An efficient instruction set is an important contributor to low energy usage. RISC controllers typically operate in a frequency cycle, but some architectures (such as CISC controllers) divide the frequency
down before it reaches the CPU. This leads to confusion about which clock frequency is actually required to execute the target application. Circuit designers should therefore have a closer look at the instruction set architecture before they compare the power consumption data of different microprocessors. As mentioned above, it is impossible to compare the values of the different energy-saving modes as they stand. So following the terminology of the vendors Microchip, NEC and Texas Instruments, who represent some of the major players in the low-power market, we will now look more closely at the most important power saving modes in order to achieve a sensible comparison of the values for available lowpower µCs in Tables 1 and 2. Run Mode The energy factors in Run or Dynamic Mode (Microchip), also known as Active Mode (TI) or Normal Mode (NEC), are operating voltage, frequency, architecture, the time required to execute instructions and technology. In other words, energy consumption is the product of Ub x Idd x execution time. A shorter execution time leads to a shorter Continued page 36> eTech - ISSUE 4
35
DESIGN REVIEW
DESIGN REVIEW
< Continued from page 35
manufacturers NEC, Microchip and Texas Instruments define their respective sleep modes.
(1MHz, 3V) in Run Mode, 30µA in Deep Sleep Mode and 0.2µA in Deep Power Down Mode.
active time and therefore to lower power consumption. The execution time, on the other hand, is determined by single cycle commands, the architecture of the instruction set and the clock frequency, and it is expressed in MIPS. Data sheet values for Run Mode therefore have to show the clock frequency and the operating voltage to be comparable. As an example, it is odd to see voltage values like 1.8V, which no battery delivers but which leads to low power consumption. And what is the point of showing this value if the On-Chip AD converter only works with a minimum of 2.2V? In both cases we can assume that it is for marketing reasons.
Idle Mode The Idle Mode does not seem to be given as much prominence and it is only listed in a few data sheets. Depending on the manufacturer, the CPU and the non-volatile memory are inactive in this mode. On the other hand, the peripherals, including interrupt controller, event system and DMA controller, continue to be active. Any interrupt will wake the system up.
Regular readers of Elektronik Industrie will already have seen Atmel’s 8-bit/16-bit AVRXmega Controller in some of the high-tech toys that we dismantle in each issue. The controllers require 365µA at 1MHz in Run Mode and 1.8V or 790µA at 3V. In Idle Mode, the values are 135µA or 255 µA respectively. For the Power Down Modes the following values are given: 0.1µA (all functions deactivated) or 1.1µA (WDT, sampled BOD). Finally, in Atmel‘s Power Save Mode the values are 0.55µA at 1.8V or 1.15µA at 3V.
16bit TIMER/ EVENT CONTROLLER 00
TO00/TIO10/PO1 T1000
PORT 0
2
P00, P01
PORT 2
6
P20, P25
PORT 3
3
P30, P35
PORT 6
2
P60, P61
PORT 12
3
P121, P122, P125
RxD6/P61
When measuring the power consumption in Run Mode, it is also relevant whether the PLL that determines the clock frequency is active or not and which division factor it uses.
T151/P30
8-bit TIMER S1
TOH1/P30
8-bit TIMER H1
INTERNAL LOW-SPEED OSCILLATOR
Current consumption
WATCHDOG TIMER RxD6/P61
10% Duty Cycle
Active Icc
78K/0 CPU CORE
FLASH MEMORY
SERIAL INTERFACE UARTS
TxD6/P60
SERIAL INTERFACE IICA
INTERNAL HIGH-SPEED RAM
AVREF
Sleep Icc
INTERNAL HIGH-SPEED OSCILLATOR
AMP0+ /P22 NOTE AMP0- /P20
VOLTAGE REGULATOR
RxD6/P61 INTP0/P00
Fig. 1: Since µCs are often in sleep mode for long periods of time, the values for this operating mode should be very low, which improves the total energy footprint. (Picture: Atmel)
INTP1/P30, INTP2/P31, INTP3/P32
X2/EXCLK/P122
OPERATIONAL AMPLIFIER 0
NOTE
Time
RESET/P125 X1/P121
6
AMP0OUTNOTE / PGAINNOTE/P21
TOOLCO/X1, TOOLC1/P31 TOOLDO/X2, TOOLD1/P32
SYSTEM CONTROL
A/D CONVERTER ANIO/P20 to ANI5/P25
POC/LVI CONTROL
RESET CONTROL
ON-CHIP DEBUG
SDAAO/P61 SCLAO/P60
Average current
POWER ON CLEAR LOW VOLTAGE INDICATOR
3
REGC
OSC2/CLKO
OSC1/CLKI
RAM
EEPROM
PORTA Timing Generation PORTB
INTRC Oscillator
VDO
VSE
PORTC
PORTD
SR Latch
ADC 10-Bit
Timer0
Timer1
Timer2
Timer4
Timer6
Comparators
LCD
ECCP1
ECCP2
ECCP3
CCP4
CCP5
MSSP
EUSART
PORTE
Fig. 2: Architecture of the PIC16F193x. (Picture: Microchip)
Sleep Modes In many applications the controller does not run continuously and the peripherals, too, are mostly idle (Fig. 1). In this case, the total energy consumption can be reduced through the various sleep modes. In Sleep Mode, the CPU and peripherals are supplied with voltage, but they remain without clock frequency and additionally the RAM content is retained. Among the different sleep modes there are fine differences to be observed. In Table 1, we have summarised how the
36
Wake-Up Time Another factor in the energy footprint is the wake-up time, i.e. the time that the controller takes to wake up from sleep mode. In the simplest case, waking up can be triggered by a keypress, or it can be caused by bus activity, receiving signals from an IR source, Bluetooth activity etc.
CPU
MCLR
eTech - ISSUE 4
The 8-bit controller ML610Q4xx from Rohm is brand new on the market. This ultra-low-power controller with RISC architecture and three-level pipeline processes one instruction per clock cycle and uses embedded Flash at 3.6V down to 1.1V. It comprises LCD drivers for 144 to 1,536 segments, up to 64KB Flash/ROM as well as 4KB RAM. It features extensive peripherals and interfaces plus on-chip debugging. Power consumption is given as 0.5µA in Halt Mode and 0.15µA in Stop Mode
INTERUPT CONTROL
Fig. 3: Architecture of the µPD78Kx2-L. (Picture: NEC Electronics) Program Flash Memory
Maxim offers the MAXQ2000, a 16-bit µC with an LCD interface for actuating up to 100 RGB segments. This was originally developed for use in blood glucose monitors, but it is equally suitable for any other high-performance, low-power application. It can be clocked at 14MHz (Ub = 1.8V) or 25MHz (Ub = 2.25V) and uses only 190µA at 8MHz and 2.2V. Maxim gives the values for the lowest power Stop Mode as typically 700nA, and in addition there is a Low Power 32kHz Mode and a Divide by 256 Mode.
It is important that the CPU is woken up in every case and this means that the sleep mode must not be too deep. A number of requirements have to be met before the CPU can start to work and among these is the presence of a clock frequency. The frequency can be supplied very quickly by an on-chip RC oscillator, up to 1000 times more quickly than by an external or an integrated quartz oscillator. For this reason, some low-power µCs use a dual startup in which the RC oscillator is used first to shorten the startup time and then later, when greater precision is required, the CPU takes its frequency from the quartz oscillator. Typical representatives of Low-Power µCs Three families of microcontrollers that can be compared with the least difficulty are manufactured by Microchip, NEC and Texas Instruments. They are summarised in Table 2 and, in the full text of the article available on the eTech website, we provide a short overview of them in alphabetical order. The values compared here were taken from the manufacturers’ data sheets. In Sleep Mode, the processor requires 2mA (12 MHz), which drops down to 6µA in Deep Sleep Mode and further to 220nA in Deep Power Down Mode. The 32-bit LPC1343 with Cortex-M3 core requires 330µA
Summary Choosing the right low-power microcontroller is a difficult task. In the end, it will be the application area that determines which type should be used. And often, rather than the bare technical details, it is environmental conditions, such as the size of the battery and the required peripherals, that determine the final choice. You have to take into account the size of the application, the type and the voltage of the battery (there is a trend to single battery cells), whether the battery fits into the application’s dimensions, the available power footprint and how easy it is to change batteries in the application. In addition, there is often no point in researching low power if low voltage is the critical criterion, e.g. to keep a clock running for a long time. The range of derivatives for the different microcontrollers is huge because of the differing application requirements outlined above. This means that developers will still have to trawl through the details of hundreds of pages of data sheets, especially since their marketing-driven front pages are often less than helpful. The large number of low-power microcontrollers described above indicates that this segment, which up to now has been dominated by Microchip, NEC and TI, is developing into a profitable niche market for a number of vendors.
Seiko Epson offers the S1C17701, a 16 Bit RISC µC with C-optimised code and serial ICE support. This controller too has LCD drivers for 56 x 32 segments as well as 64KB Flash and 4KB RAM. It is designed for clock frequencies up to 8.2MHz and the low operating voltage of 1.8V. Peripherals are comprehensive and among these, the IR controller deserves special mention. Low power values are given as 1µA in Sleep Mode and 2µA in Halt or Standby Mode. Silicon Labs has the C8051F93x/92x controllers in their product range. These can work with voltages from 0.9V to 3.6V and therefore target applications with one or two battery cells. In applications with one cell, a DC/DC converter is used. The 8051 core delivers 25 MIPS at 25MHz and 70% of all instructions are processed in one or two clock cycles. The controller with 10-bit ADC, 64KB or 32KB Flash and 4KB RAM features SmartRTClock, which means that, in addition to an internal 24.5MHz oscillator (2% accurate), it also provides an oscillator for 32kHz or an internal self-oscillate mode. The two clock sources can be switched on the fly, which is a useful feature for the different energy saving modes. Power consumption values for Idle Mode (CPU inactive) are 165µA at 1MHz and 1.8V or 235µA at 3.6V. When SmartRTClock is used, this reduces to 84µA. In the so-called Suspend Mode, the values are 77µA (two cells) and for Sleep Mode (SmartRTClock on) they are given as 0.6µA (1.8V), rising to 0.85µA at 3.6V. In absolute Sleep Mode, the values are 0.05µA (1.8V) or 0.12µA (3.6V). The SiLabs data sheet provides a formula for calculating the power that is drawn from the battery and this also includes the efficiency of the DC/DC converter. This should be taken into account for all controllers with DC/DC converters or load pumps. Apart from the above-mentioned low-power micros, there are models from Freescale (S08LL16 and V1 ColdFire) and STMicroelectronics (STM32F101x8/xB).
Get more online... For more information on the independent reviews carried out go to Design Review at www.rs-components.com/etech
eTech - ISSUE 4
37
CUSTOMER PROFILE
Q
uick
uestions
Key Facts Company Name
EquipIC supply chain
Year established
2005
Location
Haarlem, the Netherlands
Number of employees
12
Key market
Turn key supply chain services
Website
www.equipic.com
Interviewee name
Geert Jan Davids
Interviewee position
Founder and CEO
What is your latest product? We provide turnkey supply chain services for fabless semiconductor & system companies. What differentiates your products? Our ability to take customers from design (if needed), through manufacturing test and assembly through to volume production. EquipIC is differentiated with its strong background in all aspects of IC sourcing – Process selection, Design, Production, Test all based upon our excellent cooperation with Design teams, Foundries, Test & Assembly houses. What new technologies does your product employ? We employ the complete spectrum of foundry processes, including deep submicron down to 28nm How did you equip yourselves with knowledge of this new technology? We draw on our many years experience of supply chain services, as well as our close relationships with our partners. Combined with project management and in depth knowledge of all commercial aspects. Give an example of the impact one of your products has on, or the benefits it provides to, the end user. We’ve completed over 40 designs, in many cases taking over the silicon development and allowing our customer to focus on their own product development/IP development and marketing/sales. Projects have ranged from satellite terminals to hearing aids.
38
eTech - ISSUE 4
Geert Jan Davids, Founder and CEO
How do you learn about new technologies? We generally find out about new foundry, packaging and test technologies before the open market generally through our close relationships with our technology partners. How do you gain new skills? The EquipIC team each has at least 20 years of experience of silicon development, test and assembly. We work continuously to ensure that our skills are kept up to date, adopting new design approaches and technologies as they emerge. What RS service do you find most useful in your job and why? If it’s on the RS website today as in stock, we know we can have it here in our lab tomorrow. What technology do you foresee having the biggest impact on your next product? Very high volume analogue rich designs using relative mature technologies such as 0.35u, 0.18u & 0.13u CMOS. What is the biggest threat to your business? The very high cost of the next generation of deep submicron processes puts them out of reach of some start up companies.
Where innovative products are just the beginning. Molex has a reputation for setting standards and paving the way for new solutions –– from the world’s smallest interconnects to some of the highest density power connectors on the market. And we do it all to ensure that our customers have the tools they need to deliver nextgeneration technology.
Where do you see your industry in 5 years? Very much larger as it is becoming increasingly difficult for end customers to deal with the fabs directly.
rswww.com/molex
But at Molex, innovation isn’t only about products. We’ve also taken an uncompromising stance on sustainability and environmental issues. We insist on ecofriendly business practices and have dramatically increased recycling efforts, reduced energy usage and emissions, and committed ourselves to developing products with minimal environmental impact.
At Molex, we put innovation at the center of everything we do — whether that means finding new ways to meet customer challenges or going beyond the call for the global environment.
LUNCH BREAK
WIN
LUNCH BREAK
a Panasonic Blu-ray Player with our killer sudoku
Daily No. 1640 13
Easy 18
16
4
17
Name:
8
Job Title:
8
8
14
Ship-To-Number:
9
16
Tel:
21
E-mail:
13
26
4
24
16
16
7
It is not permitted to repeat a number in a shape. If you have a sum of 8 across three cells, this cannot be 2’, ‘4’, ‘2’ as the ‘2’ is then repeated in the shape.
15 The grid is composed of shapes with a dotted outline. At the top of each shape is a number, this signifies the sum of the cell. For example; if there is a shape composed of two cells with a ‘3’ in the corner, the total of those cells is ‘3’. From that you can tell that the values of the cells must be ‘1’ and ‘2’ or ‘2’ and ‘1’.
10
No numbers are placed in the grid to start with, unlike in normal sudoku; however you can work out every number with no guesswork but applying logic alone to reach the unique solution for each puzzle.
Terms & Conditions: This competition is being run by RS Components Ltd. To enter the competition, all information on the entry form must be supplied. Entry is free, no purchase is necessary. It is the responsibility of the participant to gain permission from his/her employer to enter this competition. The prize is as stated and exact specification will be selected by RS and is subject to availability.. No cash alternatives are available. The competition is open to all RS Components catalogue recipients, except employees of RS Components or their families. The closing date for entries is 01/12/2010. The date of the draw will be in the month of December 2010. The winner will be selected at random by RS Components and will be notified by 1st January 2011. Responsibility cannot be accepted for lost entries, damaged or delayed in transit to the porters address. Illegible, altered or incomplete entries will be disqualified. Details of the prize winner can be obtained from the promoter after the date of the draw by sending an SAE to RS Components, eTech Team, DPN 24, Corby, Northamptonshire, NN17 9RS or by visiting www.rs-components.com/etech.
16
16 How to play: As with standard sudoku, every row and column and 3 x 3 square must contain the numbers 1 through 9 exactly once.
Send your completed Sudoku to: RS Components Ltd, eTech Team, DPN 24, Corby, Northamptonshire, NN17 9RS.
17
12
6
3
10
22
11
9
Copyright (c) 2009, killersudokuonline.com
Whatever, Whenever Technology quiz! 1
5 A solar panel is rated at 10 Watts and provides current 8 What was the first 1G system to start operating
What does NIR stand for? a.
2 CCD Image sensors are gradually being replaced
by CMOS image sensors. What does CCD and CMOS stand for? a.
3 What are Thermopower Waves?
4
40
eTech - ISSUE 4
What will InstaLoad prevent?
a.
6 What do the following battery technologies stand for:
7
a.
of 600 mA in bright sunshine (1000 W m2). What is the estimated power output of the panel (in amps/hour)? Assume 8 hours of sunshine.
LiIon, NiCad, NiMH, LiMnO2, SLA and Li/SOC12 ? a.
a.
9 In reference to access technologies, what do the
following stand for: (FDMA, TDMA, CDMA)? a.
10 The future 4G mobile device will be first and foremost a computer, then an OWA low-power terminal. What does OWA stand for?
Give three examples of User interface (UI) controls. a.
and in which year?
a.
a.
Answers can be found at
www.rs-components.com/etech
eTech - ISSUE 4
41
INDUSTRY NEWS
Robots get an artificial skin A mobile robot carefully transports a sample through a biotech lab where it is surrounded by the routine hustle and bustle. Lab technicians are conversing with one another and performing tests. One technician inadvertently runs into the robot, which stops moving immediately. An artificial skin covering the robot makes this possible. Consisting of conductive foam, textiles and an intelligent evaluation circuit, the sensor system detects points of contact and differentiates between gentle and strong contact. It registers people immediately. The shape and size of the sensor cells implemented in the skin can be varied depending on the application. They detect any contact. The higher the number of sensor cells, the more precisely a point of collision can be detected. A sensor controller processes the measured values and transmits them to the robot or, alternatively, a computer, a machine or production line. Researchers at the Fraunhofer Institute for Factory Operation and Automation IFF in Magdeburg designed and patented this sensor system in 2008 for its assistant robot LiSA, which stocks incubators and measuring instruments in biotech labs with sample cups and relieves lab staff from such work. Since then the engineers have refined the sensor system for a wide array of applications such as industrial robots and flooring. Contact with humans or objects will be reliably detectable in the future, a basic prerequisite for the implementation of robots in human environments without protective barriers. “Our artificial skin can be adapted to any complex geometry, including curved or very flat. We use large-area floor sensors to define safety zones that people may not enter”, says Markus Fritzsche, researcher at the Fraunhofer IFF. “These areas can be changed dynamically.” The tactile skin now also functions as an input medium, for instance, to guide robots by translating contact into motion. “This requires little force. If I touch the robot, it attempts to evade the pressure. Thus, I can direct even a 200 kilogram robot in the desired direction”, says Fritzsche describing the system’s advantages. Another of the artificial skin’s distinctive features is the integrated damping elements that additionally diminish any collisions by cushioning impacts. Diverse variants of the tactile sensor system now exist, the shell material ranging from breathable to waterproof. “This opens entirely new fields of application such as medical engineering or manufacturing”, says Fritzsche. “Pressure sensitive flooring is ideal for monitoring workspaces in factories or instantly registering fallen patients in a nursing home for instance. Robots and mobile equipment outfitted with the artificial skin register any collision and brake immediately. In addition, we can provide robot grippers a sense of touch and thus detect whether they are actually gripping something.” Numerous variants of the artificial skin have been prototyped. Fritzsche is convinced: “We’ll encounter all sorts of forms of artificial skin in everyday life in the near future.”
42
eTech - ISSUE 4
Pressure sensitive flooring detects people and slows or stops the robot’s movement. (© Fraunhofer)
“
Our artificial skin can be adapted to any complex geometry, including curved or very flat. We use largearea floor sensors to define safety zones that people may not enter”
”
Markus Fritzsche, researcher at the Fraunhofer IFF
DesignSparkPCB
LET YOUR CREATIVITY FLOW The World’s Most Powerful Free Schematic and PCB Layout Tool is yours to download now Free from practical design limitations on board area, layers and pin counts, DesignSpark PCB generates industry standard manufacturing files. Key features such as the New Component Creation Wizard, the ability to import designs and libraries from Eagle, import dxf files for complex board shapes and interface with 3D CAD tools, speed up design cycles. With a modern and intuitive userinterface the software is easy to learn and easy to use.
Download your free copy at www.designspark.com/pcb
WIRED BY
e Se us in d an St 4, lA al H 7 11
see WHAT YOU MigHT sPARK DesignSpark is a new online gateway connecting electronic design engineers like you with the latest information and resources. Join the growing band of members to exchange ideas, share expertise, make contacts, grow your network and, of course, unleash that brilliance.
www.designspark.com
pOWErED BY
