The Raspberry Pi is a computer with no casing, no keyboard, no hard disk and no screen. Despite all that, it’s taking the world by storm!
Get your free Raspberry Pi poster now, courtesy of Elektor, RS Components, and CC! Go ahead: download, print, and then enjoy!
Free Raspberry Pi Poster
RASPBERRY PI ESSENTIALS
Model A has 256-MB RAM, one USB port, and no Ethernet port (network connection). Model B has 512-MB RAM, two USB ports, and an Ethernet port.
The Raspberry Pi Model B, revision 2 board:
Status led labels: top led has label “ACT” and bottom led has label “100”
Header P2 is not populated
The text underneath the Raspberry Pi logo reads: “(C) 2011,12”
The area next to the micro usb port has CE and FCC logos and the text “Made in China or UK” along the board edge.
There are two 2.9-mm holes in the PCB, which can be used as mounting holes.
P5 is a new GPIO header with four additional GPIO pins and four power pins. Also note that some pin and I2C port numbers of connector P1 have been modified between revisions!
Header P6 (left from the HDMI port) was added, short these two pins to reset the computer or wake it up when powered down with the “sudo halt” command.
The Raspberry Pi measures 85.60 mm × 56 mm × 21 mm, with a little overlap for the SD card and connectors which project over the edges. It weighs 45 g.
The SoC is a Broadcom BCM2835. This contains an ARM ARM1176JZFS, with floating point, running at 700 MHz, and a Videocore 4 GPU. The GPU is capable of BluRay quality playback, using H.264 at 40 Mbps. It has a fast 3D core which can be accessed using the supplied OpenGL ES2.0 and OpenVG libraries.
The Raspberry Pi is capable of using hardware acceleration for MPEG-2 and VC-1 playback, but you’ll need to buy license keys at the Raspberry Pi Store to unlock this functionality.
Which programming languages can you use? Python, C/C++, Perl, Java, PHP/MySQL, Scratch, and many more that can run under Linux.
TROUBLESHOOTING TIPS
If you’re getting a flashing red PWR LED or random restarts during the booting process, it’s likely that your PSU or USB cable has problems. The Raspberry Pi is pretty picky and requires a solid 5-V/1000-mA power supply. For other issues and more troubleshooting tips check out the extensive overview at the eLinux website
Circuitcellar.com is an Elektor International Media 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.”
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)
USB technology started becoming relevant in the mid-to-late 1990s, and since then has become the go-to connection option for designers and end users alike. Turn to page 30 for Jan Axelson’s tips about debugging USB firmware. Axelson covers controller architectures and details devices such as the FTDI FT232R USB UART controller and Microchip Technology’s PIC18F4550 microcontroller.
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)
Domotics (home automation) control systems are among the most innovative and rewarding design projects creative electrical engineers can undertake. Let’s take a look at an innovative Beagle Board-based control system that enables a user to control lights with a 10.1˝ capacitive touchscreen.
• An I/O board for testing purposes
• An LED strip board for controlling an RGB LED strip
• A relay board for switching 230-VAC devices
• An energy meter for measuring on/off (and also for logging)
ELektor editor and engineer Clemens Valens recently interviewed Koen van Dongen about the design. Van Dongen describes the system’s electronics and then demonstrates how to use the touchscreen to control a light and LED strip.
As Valens explains suggests, it would be a worthwhile endeavor to incorporate a Wi-Fi connection to enable cellphone and tablet control. If you build such system, be sure to share it with our staff. Good luck!
CircuitCellar.com is an Elektor International Media website.
