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.
Member Status: He has been a subscriber since day one. “I’ve got Issue 1 sitting in a box somewhere,” he said. Thomas adds that he was a BYTE magazine subscriber before Circuit Cellar.
Technical Interests: Thomas enjoys automation through embedded technology, robotics, low-level programming, and electronic music generation / enhancement.
Most Recent Embedded Tech-Related Purchase: He recently bought a CWAV USBee SX Digital Test Pod and an Atmel AVR Dragon.
Current and Recent Projects: Thomas is working on designing an isolated USB power supply for his car.
Thoughts on the Future of Embedded Technology: Ever-increasing complexity is becoming a stumbling block for the “average” user. “Few people even realize the technology embedded in everyday items,” he said. “How many people know that brand-new LCD TV they’ve got is actually running Linux under the covers? Fortunately, there seems to be a resurgence of ‘need-to-know how stuff works’ with the whole DIY/maker culture. But even that is still a small island compared to the population in general.”
Every time the Arduino team is about to release a new board, we expect something great in terms of better specs, more I/Os, a faster processor, more memory—or, well, just something to “fill the gap,” such as small-scale versions. With “Esplora” the Arduino team pleasantly surprises us again!
The brand new Esplora is targeted toward gaming applications. It consists of a gamepad-shaped development board that includes an Arduino-compatible Atmel ATmega32U4, a light sensor, a temperature sensor, an accelerometer, a joystick, push buttons, a slider, an RGB LED, and a buzzer.
The Esplora is as a ready-to-use solution for designers who don’t want to deal with soldering or prototyping by means of discrete components. In fact, it comes preprogrammed with a controller script, so you only have to connect it to a PC, download the free game “Super Tux Cart,” and have fun.
An additional color LCD will be released soon in order to create a portable console. The only drawback is you can’t directly connect standard Arduino shields to it , mainly because of space limitations. Nevertheless, the board itself includes enough features to make it interesting.
The Esplora should enable you to implement a controller for almost any application you dream up. In our case, we’re sure it will bring back nice memories of the time when we were too young for soldering irons but already pros with gamepads!—Jaime González Arintero Berciano, Elektor International Media
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)
At the end of September 2012, an enthusiastic crew of electrical engineers and journalists (and significant others) traveled to Portsmouth, NH, from locations as far apart as San Luis Obispo, CA, and Paris, France, to celebrate Circuit Cellar’s 25th anniversary. Attendees included Don Akkermans (Director, Elektor International Media), Steve Ciarcia (Founder, Circuit Cellar), the current magazine staff, and several well-known engineers, editors, and columnists. The event marked the beginning of the next chapter in the history of this long-revered publication. As you’d expect, contributors and staffers both reminisced about the past and shared ideas about its future. And in many instances, the conversations turned to the content in this issue, which was at that time entering the final phase of production. Why? We purposely designed this issue (and next month’s) to feature a diversity of content that would represent the breadth of coverage we’ve come to deliver during the past quarter century. A quick look at this issue’s topics gives you an idea of how far embedded technology has come. The topics also point to the fact that some of the most popular ’80s-era engineering concerns are as relevant as ever. Let’s review.
In the earliest issues of Circuit Cellar, home control was one of the hottest topics. Today, inventive DIY home control projects are highly coveted by professional engineers and newbies alike. On page 16, Scott Weber presents an interesting GPS-based time server for lighting control applications. An MCU extracts time from GPS data and transmits it to networked devices.
The time-broadcasting device includes a circuit board that’s attached to a GPS module. (Source: S. Weber, CC268)
Thiadmer Riemersma’s DIY automated component dispenser is a contemporary solution to a problem that has frustrated engineers for decades (p. 26). The MCU-based design simplifies component management and will be a welcome addition to any workbench.
The DIY automated component dispenser. (Source: T. Riemersma, CC268)
Debugging USB firmware (Source: J. Axelson, CC268)
Electrical engineers have been trying to “control time” in various ways since the earliest innovators began studying and experimenting with electric charge. Contemporary timing control systems are implemented in a amazing ways. For instance, Richard Lord built a digital camera controller that enables him to photograph the movement of high-speed objects (p. 36).
Security and product reliability are topics that have been on the minds of engineers for decades. Whether you’re working on aerospace electronics or a compact embedded system for your workbench (p. 52), you’ll want to ensure your data is protected and that you’ve gone through the necessary steps to predict your project’s likely reliability (p. 60).
The issue’s last two articles detail how to use contemporary electronics to improve older mechanical systems. On page 64 George Martin presents a tachometer design you can implement immediately in a machine shop. And lastly, on page 70, Jeff Bachiochi wraps up his series “Mechanical Gyroscope Replacement.” The goal is to transmit reliable data to motor controllers. The photo below shows the Pololu MinIMU-9.
The Pololu MinIMU-9′s sensor axes are aligned with the mechanical gyro so the x and y output pitch and roll, respectively. (Source: J. Bachiochi, CC268)