Sunday 8 July 2012

Circuit for Wheelchair Robot

Earlier this year I decided to turn one of my old wheelchairs into a robot.  I really had no idea where to start fortunately I came across a website called Critical Tinkerers who are a student group out of Iowa State University.  They had done exactly what I wanted to do and the best thing is they published exactly how to do it.  It involved mimicing the output of the joystick it was a fairly simple circuit using an arduino microcontroller a digital to analog converter (DAC) and two amplifiers to increase the voltage to match the the output of the joystick.

I managed to build the circuit with a bit of help of my carers in my stepdad Peter. However when it became time to connect it to the wheelchair it was different to what I expected, the circuit was not designed for this joystick.  I had made an assumption that the joystick was the same as the one the Critical Tinkerers wheelchair but it was completely different.  The Critical Tinkerers wheelchair had 2 inputs an X and Y where as my one had 4 imputs 2 X's and 2 Y's. Thankfully I was able to use some elements of their circuit in a new circuit it was actually much simpler it uses 2 digital to analog converters with no amplifiers.  However I didn't have enough DAC's to make the new circuit so I've had to order more.  When they arrive I should have a robot hopefully.

This is the Critical Tinkerers circuit.

My circuit with ribbon cable plug, the green circuit below is a radio receiver, You can also see a bit of the critical tinkerers circuit in the bottom right.

This is a dynamic wheelchair controller.

This is the backside of the controller. Ribbon cable attached in the top right.

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