Can a Pi Raspberry?

The Raspberry Pi is a small computer, and as such an obvious but important question occurred to me, and despite Google, I was unable to find an answer. So using science, LEGO, a balloon, and a compressed air supply I set out to discover if the Raspberry Pi could indeed blow a raspberry.

To embark on this scientific discovery, first, I needed to be able to control a motor, for this I built a dual relay board that can be switched using a couple of the Pi’s GPIO pins:

LEGO PF Motor Controller v3

Here is the circuit diagram:

LEFO PF Motor Controller v3

And the Python source code:

To which I connected a large LEGO PF motor. This is used to switch the pneumatic valves via a clutch cog and a large cog. I used a 9v power supply for this, but a PF Battery box can be used, cut an PF extension lead in half, use the light grey side for the motor, and the dark grey end to connect to the battery box. My compressed air supply operates at 2bar / 30 psi, it was built to work with LEGO pneumatics, I found that anything much above that pressure would cause the pipes to pop off the connectors.

The Pi Raspberry Project

Obviously I needed something that would make a sound. For this, a balloon (the sausage type), a small pop bottle, and some more LEGO were suffice. The air is injected into the bottle trough a couple of holes at the rear.

The Pi Raspberry Project

I would like to say thanks to the people on the Raspberry Pi forum for their advice on the electronics: http://www.raspberrypi.org/phpBB3/ and further reading about LEGO PF motors can be found here: http://www.philohome.com/pf/pf.htm, and the raspberry http://en.wikipedia.org/wiki/Blowing_a_raspberry

2 thoughts on “Can a Pi Raspberry?”

  1. Hi, I’m a bit of an electronics noob, but why did you use an optocoupler in the circuit, surely there is not much need to insulate the two sides and just use a standard transistor instead

    Thanks

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