Check out this great guest blog story from the Raspberry Pi Foundation written by 14-year-old Ben J:
I’ve always had a big interest in robotics and electronics in general, so when I heard about the Raspberry Pi, I knew I had to build a robot around it. This is what I came up with … A robot, ready to do your bidding. (Necessary wifi dongle not shown.)
The base of the robot is an old iRobot roomba 4000 with all of the cleaning brushes and their respective motors removed.
The model of roomba that I used has two drive wheels and a coaster wheel in front, and the drive wheels draw almost 300mA of current, so powering them directly off of the Raspberry Pi’s GPIO obviously wouldn’t work. So, I considered using a relay board to control the two drive motors from the GPIO. However, it turns that all the good boards were a little too expensive for a hobby project, so I decided to open the roomba up and see if I could somehow control the motors from the existing circuitry. Guess what? It turns out that there are four small transistors on the main board that power four larger transistors that deliver power to the motors. This means that there are two transistors per motor: one for forwards and one for backwards.
Driving the project around.
Each Friday is PiDay here at Adafruit, be sure to check out our posts, tutorials and new Raspberry Pi related products. Have you tried the new “Adafruit Raspberry Pi Educational Linux Distro” ? It’s our tweaked distribution for teaching electronics using the Raspberry Pi. But wait, there’s more! Try our new Raspberry Pi WebIDE! The easiest way to learn programming on a Raspberry Pi.
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