[dtengineering]

Thanks for the kind words Qbranch... and you should have good luck with the Tamiya gearbox and L293 3Dude... over the past five or six years we must have made more than 100 mini robots using this set up in my shop alone.

One issue that you might come across is that depending on what your power supply is, when you start the motor it may pull the supply voltage down below the minimum voltage that the PIC requires to operate. As soon as the PIC shuts down, so does the motor... the PIC reboots... tries to restart the motor... and, well... you can see a loop there. The solution we use is to put the logic voltage on one circuit (a 5v regulated 9V battery) and the drive voltage on another (4 x AA battery pack). This is far from the only solution, but this situation and solution is quite common... witness the backup battery for the RC on your team's robot for the exact same situation.

I'll attach an older .pdf of one of my handouts... some of the stuff is a bit out of date... we don't use the 16f84a chip anymore, so the crystal and such aren't necessary, but the last two pages have some info on how we hook up the electronics that should be relevant to your project.

I'll also include a worksheet I give my students on the Sony IR protocol. Any Sony remote (or any multi-brand remote set to emulate a Sony) can easily be read by a PIC if you attach a PNA4602m (less than a buck each, if I recall) to one of the pins on the PIC and throw in a few lines of code.

You might find this a fun and cheap alternative to RC.

Have fun,

Jason