Fischertechnik, Scratch and Motor Control through the GPIO.

Fischertechnik robot arm connected to two L298 driver boards and controlled through Scratch.

My greatest interest in the Raspberry Pi lies in those 26 little pins tucked down on the side of the board. They just invite things to be connected to them. Having found a pile of dusty Fischertechnik (loosely assembled in a sort-of robot arm shape) in a cupboard, I decided that something could be done with it.
The arm was so dusty it needed disassembling and washing. I left the motors and sensors out of the wash but I figured that everything else would cope. Sure enough, it looked like new again.

I found some L298 motor driver boards on Ebay and these easily connect to the Raspberry Pi GPIO connections. There are four motors in this arm:

• Rotation of the base
• Lifting of the “forearm”
• Lifting the “upper arm”
• Closing the jaws

“The Arm”… Servoblaster, Raspberry Pi and a Python program

This little video demonstrates the arm repeatedly picking up and moving a small object. The arm uses three servos, a simple buffer board and a few bits of plastic.
The next development will be to modify the program so that it can shuffle the pieces of plastic.

ServoBlaster and “The Arm”

The next challenge was to try to create a simple robot arm that could be easily cut out on a CAM router and assembled with a glue gun, and yet be sufficient to demonstrate some programming techniques. It actually works rather well although it is a bit lightweight and has a tendency to skip across the table. It also misses the target pieces if someone fiddles with them, but that’s not the fault of the robot…

This robot is made of foamed PVC board, cut on a CAM router and assembled with hot glue.

I’ve uploaded a few files for “The arm” in PDF format but I also have them in wmf and dxf so maybe others can make use of them. However, I can’t upload them here as they’re not supported without me having to pay…

ServoRobot – Page2 ServoRobot – Page1 RobotArm- dimensions