Has anyone ever used the internals from a mouse to count or measure distance? How easy was it? What signals do I look for? Which parts can I do without, and which parts must I keep? I am just starting and guidance would be appreciated. Jack
Hi Jack.
Based on a suggestion from Gordon McComb in this very newsgroup, I used a mouse to encode movement of my robot's drive motors. I had to remote mount the LED/phototransistor pairs (remove from the mouse board and install on a custom PCB), and modify the encoder wheels to attach to the motors.
Then I had to write microcontroller software to implement the PS/2 mouse communication protocol. The PS/2 hardware interface has +5V, GND, DATA, and CLOCK signals. This is all documented on the web (use your favorite search engine).
I read a lot about people using the encoder wheels and optoelectronics from mice, but I thought Gordon's suggestion of using the whole thing was rather elegant. The microcontroller in the mouse tracks movement of the encoders and stuffs the information in to a nice little three byte packet.
It works OK. How easy was it? Well, let us just say that it would have been easier to spend $100+ each on OTS quadrature encoders. But where is the adventure in that?
Jeff.
check out my URL at
eyal
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