idea: simple remote control for the robot using some cheap commercial RF transmitter (keychain size, like for cars). The receiving device will be some 3-4 pin module under an inch size. It may be used as a kill switch as well as to send 2-3 other simple commands. I wonder if this could be done under $20?
SparkFun carries something like what you’re talking about, the Nordic FOB. The transmitter alone will cost you $25, plus another $20 for a receiver.
I think it is manageable. Look at:
- seeedstudio.com/depot/2km-lo … ml?cPath=2 2km range, 18.5 USD however…
- the pololu switch 6.5 euros
- some form of keyfob casing, see ebay, around 2 euro OR
sold as a RC control unit plugin attachment (using a spare channel, etc).