BeagleBone Black project spotlight:
Robotics Cape by Strawson Design
Inspiration is not an easy thing to come by, and no one can predict when it will strike. The light bulb suddenly flashes on overhead, and the gears inside your brain start to turn. The excitement of the “Ah hah!” moment is great, but often short lived when the realization of the logistics come into play.
Engineers often find themselves in this situation when a new idea for a robot pops into their head, but then there is the complicated process of crafting the internal hardware and writing the software to actually make it work. James Strawson, PhD student at the University of California, San Diego (UCSD) and founder of Strawson Design, grew tired of having to create new circuits for every new robot that he worked on, so he unified his current and future robotics projects under one hardware and software platform, thus creating the Robotics Cape.
Robotics Cape by Strawson Design; image credit: Strawson Design
The Robotics Cape works with the BeagleBone Black, powered by a TI Sitara processor, to make a mobile robotics platform. It includes 2-cell lithium battery charging, protection and monitoring circuitry to make sure the robot is always charged and ready to play with. The Robotics Cape also provides plug-and-play connectors to easily interface with common components so you can build your robot without soldering or messy wiring. It was obvious for James to choose BeagleBone Black when picking a Linux development board. Strawson said, “First and foremost, robotics projects typically require the control board to interface with custom circuitry. BeagleBone Black provides an enormous array of hardware interface pins for functions such as GPIO, PWM, eQEP, I2C, etc., which is exactly what tinkerers and prototypers need. BeagleBone Black is also a fantastically neat and tidy package that is ideal for tiny robots.”
When creating the cape, Strawson picked the features he felt would apply to the largest number of applications. The cape offers:• 9-axis IMU: Accelerometer, gyro, magnetometer
• 6 PWM connectors to power servos or brushless ESCs
• Power your BeagleBone with 5V 2A switching voltage regulator from 12v input or battery pack
• 2 user-accessible buttons and 2 LEDs to test GPIO functionality and to test PRU GPIO
• 2-cell lithium cell balancer and overvoltage protector
• H-bridges to drive 6 DC motors (each 1.2A continuous, 3.2A peak)
• Plug-and-play connection supported:
o I2C, UART, SPI
o Range/gesture sensors
o Serial GPS module
o Spektrum™ RC receiver
o Quadrature encoder inputs
Strawson first used the Robotics Cape to teach a senior embedded controls course at UCSD. Each student built their own BeagleMIP balancing robot based on the cape and was taught to design and implement a discrete-time controller to make the robot balance upright and drive. Texas Instruments’ University Program donated BeagleBone Black computers to UCSD to enable such a wonderful project. “We learned a lot about implementing dynamic control systems in a Linux environment. I was pleased to teach fellow mechanical engineers how to dive into the world of embedded programming and circuit design,” Strawson said.
BeagleMIP balancing robot; image credit: Strawson Design
Strawson is working on a few refinements on the board layout and connectivity before bringing the Robotics Cape to market. He also looks forward to spending more time developing control systems with BeagleBone Black. He is testing a quadrotor controller based on the BeagleBone Black as well as a Robotics Cape Combination designed to be cheap and easy to repair while offering the networking capability and processing power of BeagleBone Black.
James Strawson demoing the BeagleMIP at CES 2014
The Robotics Cape is still a work in progress but will be available for sale in the coming months. For updated information on the Robotics Cape, visit Strawson Design’s website at www.strawsondesign.com.