Greetings Gadget Freaks, this week I’m in Argentina attending SASE 2010. Argentina, you may recall, is in the Southern Hemisphere meaning it’s summer here. Buenos Aires is having high temperatures in the upper 80s and humidity of roughly 115%. It reminds me a lot of summers in Houston.
Disclaimer: I’m an ARM employee, ARM is a sponsor of this event, and many of the presentations and projects here are ARM powered.
Most of the presentations are in Spanish, which I don’t really speak (I do speak enough that I can place an order at a restaurant, so I won’t starve to death). Fortunately in a technical presentation many words are English cognates so it’s not that hard to follow along. I’m pleased that FIUBA (Facultdad de Ingenieria, Universidad de Buenos Aires) has invited me to give two talks, one about ARM processor architecture and one about FPGA emulation of ARM processors. These, unfortunately for attendees, will be given in English.
So back to the gadgets. Along with the conference, which is student oriented, there are are several student project competitions. One competition is part of an mbed workshop (I’ve written previously about mbed), where students build cars that can follow a printed line on a sheet of paper. Over the course of a few hours students are introduced to mbed, assemble the car, and write the firmware that drives the car. Many of these students have never programmed a microcontroller before.
At the end of the week a large race track will be created from many sheets of paper taped together and the cars will be raced to see which finishes the course the fastest.
It’s a neat project and one that plays to the strengths of mbed, which is rapid prototyping with microcontrollers. In this case having C++ class libraries that abstract away the register details of using digital I/O and PWM means the students can concentrate on their control algorithms to get around the course as fast as possible. And having the development environment hosted online saves the instructors from having to install it on every PC.
The car itself is fairly simple. Two electrical motors drive four wheels, with one motor driving the left two and the other driving the right. These vehicles steer by slowing or reversing one motor relative to the other, in the manner of a skid steer loader.
Two sensors on the bottom of the car use ambient light to detect the edge of the black line that the car is to follow. The secret sauce, of course, is in the control algorithm. Some students use a simple on/off control algorithm that causes them to ping pong side to side as they follow the line, others have a more sophisticated algorithm that drives in straight lines and smooth curves.
The robotics club at FIUBA designed the cars and the workshop, and the racetrack with its automatic lap timer. Unfortunately I won’t be able to see the results of the race, as I’ll be leaving for the airport, and a 10.5 hour flight home, just as the race starts. Their youtube channel has some videos of the cars in action that you can enjoy, however.
Next time: 3 clever undergraduate projects that were entered in the project competition.
Best regards,
Steve Ravet
EDN Gadget Freak
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