Digital Electronics project - servos and more

[whytheheckme]

Back when I was on FRC #0181, we created a (scaled down) replica of our 'bot's arm for our OI, using pots at each joint and a button for the actuator, to control our actual arm. We won the control award for this.

It really is pretty simple. If you have pots on the controlling arm, and pots on the big arm, you just have to write a relational equation to convert the two values (example: big_pot_1 = mini_pot_1 * .86 + 28)

Then you can pick a micro-controller to handle the job. A PIC16, like we used to use with the PBASIC bots, should work just fine. Get a protoboard (total, the controller, board and cable are usually together in a package in the $50-80 range.) You can then have your pots from your controller arm input into this, and have your output to your motor controllers.

Lets assume you are using motors that you only want to control with on/off/backwards type movement. You could then get some relays (from radioshack, less than a buck a piece), and run your motor voltage through them, with your control signal running back to your micro. Attach your motors to the relays.

Finally, you need to write some code. I hope that you aren't being forced to write in assembly, although this could be done. If not, make sure that when you pick a microcontroller, you pick one in a language that is easy for you to pick up. The PBASIC and C ones should work fine. Simply read in your inputs, convert to your output theoretical value, compare to the actual arm pot value, and drive your motors in the correct direction until they match.

Hope this helps!
Jacob