How do you clean a clean-energy generating system? With a microcontroller (and a few other parts, of course). An excellent example is US designer Scott Potter’s award-winning, Renesas RL78 microcontroller-based Electrostatic Cleaning Robot system that cleans heliostats (i.e., solar-tracking mirrors) used in solar energy-harvesting systems. Renesas and Circuit Cellar magazine announced this week at DevCon 2012 in Garden Grove, CA, that Potter’s design won First Prize in the RL78 Green Energy Challenge.
This image depicts two Electrostatic Cleaning Robots set up on two heliostats. (Source: S. Potter)
The nearby image depicts two Electrostatic Cleaning Robots set up vertically in order to clean the two heliostats in a horizontal left-to-right (and vice versa) fashion.
The Electrostatic Cleaning Robot in place to clean
Potter’s design can quickly clean heliostats in Concentrating Solar Power (CSP) plants. The heliostats must be clean in order to maximize steam production, which generates power.
The robot cleaner prototype
Built around an RL78 microcontroller, the Electrostatic Cleaning Robot provides a reliable cleaning solution that’s powered entirely by photovoltaic cells. The robot traverses the surface of the mirror and uses a high-voltage AC electric field to sweep away dust and debris.
Parts and circuitry inside the robot cleaner
Object oriented C++ software, developed with the IAR Embedded Workbench and the RL78 Demonstration Kit, controls the device.
IAR Embedded Workbench IDE
The RL78 microcontroller uses the following for system control:
• 20 Digital I/Os used as system control lines
• 1 ADC monitors solar cell voltage
• 1 Interval timer provides controller time tick
• Timer array unit: 4 timers capture the width of sensor pulses
• Watchdog timer for system reliability
• Low voltage detection for reliable operation in intermittent solar conditions
• RTC used in diagnostic logs
• 1 UART used for diagnostics
• Flash memory for storing diagnostic logs
The complete project (description, schematics, diagrams, and code) is now available on the Challenge website.
Ready to start a low-power or energy-monitoring microcontroller-based design project? You’re in luck. We’re featuring eight award-winning, green energy-related designs that will help get your creative juices flowing.
The projects listed below placed at the top of Renesas’s RL78 Green Energy Challenge.
Electrostatic Cleaning Robot: Solar tracking mirrors, called heliostats, are an integral part of Concentrating Solar Power (CSP) plants. They must be kept clean to help maximize the production of steam, which generates power. Using an RL78, the innovative Electrostatic Cleaning Robot provides a reliable cleaning solution that’s powered entirely by photovoltaic cells. The robot traverses the surface of the mirror and uses a high voltage AC electric field to sweep away dust and debris.
Parts and circuitry inside the robot cleaner
Cloud Electrofusion Machine: Using approximately 400 times less energy than commercial electrofusion machines, the Cloud Electrofusion Machine is designed for welding 0.5″ to 2″ polyethylene fittings. The RL78-controlled machine is designed to read a barcode on the fitting which determines fusion parameters and traceability. Along with the barcode data, the system logs GPS location to an SD card, if present, and transmits the data for each fusion to a cloud database for tracking purposes and quality control.
Inside the electrofusion machine (Source: M. Hamilton)
The Sun Chaser: A GPS Reference Station: The Sun Chaser is a well-designed, solar-based energy harvesting system that automatically recalculates the direction of a solar panel to ensure it is always facing the sun. Mounted on a rotating disc, the solar panel’s orientation is calculated using the registered GPS position. With an external compass, the internal accelerometer, a DC motor and stepper motor, you can determine the solar panel’s exact position. The system uses the Renesas RDKRL78G13 evaluation board running the Micrium µC/OS-III real-time kernel.
Water Heater by Solar Concentration: This solar water heater is powered by the RL78 evaluation board and designed to deflect concentrated amounts of sunlight onto a water pipe for continual heating. The deflector, armed with a counterweight for easy tilting, automatically adjusts the angle of reflection for maximum solar energy using the lowest power consumption possible.
RL78-based solar water heater (Source: P. Berquin)
Air Quality Mapper: Want to make sure the air along your daily walking path is clean? The Air Quality Mapper is a portable device designed to track levels of CO2 and CO gasses for constructing “Smog Maps” to determine the healthiest routes. Constructed with an RDKRL78G13, the Mapper receives location data from its GPS module, takes readings of the CO2 and CO concentrations along a specific route and stores the data in an SD card. Using a PC, you can parse the SD card data, plot it, and upload it automatically to an online MySQL database that presents the data in a Google map.
Air quality mapper design (Source: R. Alvarez Torrico)
Wireless Remote Solar-Powered “Meteo Sensor”: You can easily measure meteorological parameters with the “Meteo Sensor.” The RL78 MCU-based design takes cyclical measurements of temperature, humidity, atmospheric pressure, and supply voltage, and shares them using digital radio transceivers. Receivers are configured for listening of incoming data on the same radio channel. It simplifies the way weather data is gathered and eases construction of local measurement networks while being optimized for low energy usage and long battery life.
The design takes cyclical measurements of temperature, humidity, atmospheric pressure, and supply voltage, and shares them using digital radio transceivers. (Source: G. Kaczmarek)
Portable Power Quality Meter: Monitoring electrical usage is becoming increasingly popular in modern homes. The Portable Power Quality Meter uses an RL78 MCU to read power factor, total harmonic distortion, line frequency, voltage, and electrical consumption information and stores the data for analysis.
The portable power quality meter uses an RL78 MCU to read power factor, total harmonic distortion, line frequency, voltage, and electrical consumption information and stores the data for analysis. (Source: A. Barbosa)
High-Altitude Low-Cost Experimental Glider (HALO): The “HALO” experimental glider project consists of three main parts. A weather balloon is the carrier section. A glider (the payload of the balloon) is the return section. A ground base section is used for communication and display telemetry data (not part of the contest project). Using the REFLEX flight simulator for testing, the glider has its own micro-GPS receiver, sensors and low-power MCU unit. It can take off, climb to pre-programmed altitude and return to a given coordinate.
High-altitude low-cost experimental glider (Source: J. Altenburg)
The 2012 Embedded Systems Conference in Boston started September 17 and ends today. Here’s a wrap-up of the most interesting news and products.
Microchip Technology announced Monday morning the addition of 15 new USB PIC microcontrollers to its line of full-speed USB 2.0 Device PIC MCUs. In a short presentation, Microchip product marketing manager Wayne Freeman introduced the three new 8-bit, crystal-free USB PIC families.
The PIC16F145x family (three devices) features the Microchip’s lowest-cost MCUs. The devices are available in 14- and 20-pin packages, support full-speed USB communication, don’t require external crystals, include PWM with complement generation, and more. They’re suitable for applications requiring USB connectivity and cap sense capabilities.
Microchip’s three PIC18F2x/4xK50 devices (available in 28- and 40/44-pins) enable “easy migration” from legacy PIC18 USB devices. In addition to 1.8- to 5-V operation, they feature a Charge Time Measurement Unit (CTMU) for cap-touch sensing, which makes them handy for data logging systems for tasks such as temperature and humidity measurement.
The nine devices in the PIC18F97J94 family are available in 64-, 80-, and 100-pin packages. Each device includes a 60 × 8 LCD controller and also integrates a real-time clock/calendar (RTCC) with battery back-up. Systems such as hand-held scanners and home automation panels are excellent candidates for these devices.
Several interesting designs were on display at the Microchip booth.
The M2M PICtail module was used in an SMS texting system.
This SMS text messaging system was featured at Microchip’s Machine-to-Machine (M2M) station. The M2M PICtail module (located on the bottom left) costs around $200.
Microchip featured its PIC MCU iPod Accessory Kit in glucose meter design. It was one of several healthcare-related systems that exhibitors displayed at the conference.
The interface can be an iPhone, iPad, or iPod Touch.
As most of you know, the entry period for the Renesas RL78 Green Energy Challenge ended on August 31 and the judges are now reviewing the entries. Two particular demos on display at the Renesas booth caught my attention.
A lemon powering an RL78 L12 MCU:
Lemon power and the RL78
An R8C capacitive touch system:
Cap touch technology is on the minds of countless electrical engineers.
I was pleased to see a reprint of Mark Pedley’s recent Circuit Cellar article, “eCompass” (August 2012), on display at Freescale’s booth. The article covers the topics of building and calibrating a tilt‐compensating electronic compass.
A Circuit Cellar reprint for attendees
Two of the more interesting projects were:
An Xtrinsic sensor demo:
Xtrinsic and e-compass
A Tower-based medical suitcase, which included a variety of boards: MED-BPM (a dev board for blood pressure monitor applications), MED-EKG (an aux board for EKG and heart rate monitoring applications), and more.
Tower System-based medical suitcase
I stopped by the STMicro booth for a look at the STM32F3DISCOVERY kit, but I quickly became interested in the Dual Interface EEPROM station. It was the smartphone that caught my attention (again). Like other exhibitors, STMicro had a smartphone-related application on hand.
The Dual EEPROMs enable you to access memory via either wired or RF interfaces. Energy harvesting is the new function STMicro is promoting. According to the documentation, “It also features an energy harvesting and RF status function.”
The Dual Interface EEPROM family has an RF and I2C interface
According to STMicro’s website, the DATALOG-M24LR-A PCB (the green board, top left) “features an M24LR64-R Dual Interface EEPROM IC connected to an STM8L101K3 8-bit microcontroller through an I2C bus on one side, and to a 20 mm x 40 mm 13.56 MHz etched RF antenna on the other one side. The STM8L101K3 is also interfaced with an STTS75 temperature sensor and a CR2330 coin cell battery.”
I’m glad I spend a few moments at the Fujitsu booth. We rarely see Circuit Cellar authors using Fujitsu parts, so I wanted to see if there was something you’d find intriguing. Perhaps the following images will pique your interest in Fujitsu technologies.
The FM3 family, which features the ARM Cortext-M3 core, is worth checking out. FM3 connectivity demonstration
Check out Fujitsu’s System Memory site and document ion to see if its memory products and solutions suit your needs. Access speed comparison: FRAM vs. SRAM vs. EEPROM
Access speed comparison
The ESC conference site has details about the other exhibitors that had booths in the exhibition hall.
Did you miss the 1:00 PM EST deadline for the Renesas RL78 Green Energy Challenge? Do you have an unfinished project? No worries! You can still make something of your RL78-related project and the work you’ve put into it! Circuit Cellar and Elektor have several exciting non-contest-related opportunities you’ll find interesting and advantageous!
The Circuit Cellar/Elektor staff wants to know about your work. Even if your project is unfinished, let the staff know what you’re working on and the project’s status. Upload your project or email us your information.
If the staff is interested in your work, an editor will consider approaching you about one or all of the following non-contest-related opportunities:
Distinctive Excellence: If the editorial team thinks your project has merit, you might be eligible for “Distinctive Excellence” designation. After past design challenges, Distinctive Excellence recipients added the honor to their resumes, wrote articles about their projects, and gained notoriety in the design community.
Print Magazine Opportunities: The editorial team might think your project is worthy of being published in Circuit Cellar or Elektor magazine. Design Challenges and the print magazine are completely separate. If you are offered an opportunity to write an article and it is published, you will paid a standard author honorarium.
CircuitCellar.com Opportunities: The Circuit Cellar editorial team will review your submission and consider posting it on CircuitCellar.com to show the world the effort and progress you’ve made. You can post your project info on the site in the spirit of sharing and the furtherance of engineering innovation! Who knows? Readers might provide you with valuable feedback about yourunfinished project. Or perhaps you’ll inspire another person to build something of their own! Perhaps your project will catch the eye company looking to learn more about you work!
Interview Possibilities: The editorial team might find your approach to design interesting and consider interviewing you for an upcoming issue.
Future Design Collaboration: The Elektor Lab builds and tests innovative electronics projects. If your project—whether finished or in progress—interests an Elektor Lab engineer or editor, someone might contact you to discuss development, testing, or even production opportunities.
As you can see, you have some excellent reasons to contact the Circuit Cellar/Elektor staff.
To submit a finished project, an abstract, or simply info about our work, you can still use the Challenge Entry Form. Or, you can simply ZIP your files and email them to the Circuit Cellar Editorial Department. (Write “RL78 Project” and your project’s name or registration number in the email’s subject line.)
Attention engineers, programmers, and electronics enthusiasts! The entry deadline of August 31 for the Renesas RL78 Green Energy Challenge is fast approaching. Here are some tips to keep you on schedule.
COMPLETE YOUR DESIGN
The challenge is to design an innovative, energy-efficient application that features the Renesas RL78 MCU, RL78/G13 Renesas Demonstration Kit (RDK), and IAR Toolchain. For information, visit the Eligible Parts page on the design challenge site.
Renesas RDK RL78 board
GATHER YOUR ENTRY FILES
Once you’re done designing your RL78-based project, you need to gather and order your entry materials: project abstract, complete documentation, and code.
Make sure you register for the challenge to obtain a registration number. Label all of your files and documents with your registration number. Don’t put your name on the files and documents.
Consider organizing all of your entry in a ZIP (or RAR) file. Compressing all of your files into one ZIP will keep your entry organized and easier to submit.
FINAL ENTRY CHECKLIST
Before you submit your entry, go through the following checklist one last time to ensure you have everything:
• Abstract (a short project description)
• Complete documentation (a detailed project description)
• Block diagram(s)
• Project photograph(s)
• Source code
• Files are properly labeled (your name doesn’t appear in the entry files)
More details are posted on the challenge’s FAQ webpage.