I need to be able to wirelessly enable a relay to turn off an autonomous lawnmower. In the past, we used a "mechanical engineer" solution of using an RC transmitter (like the kind for RC cars) which would remotely trigger a servo which turned until it hit a switch which triggered the relay.
There are multiple problems with this solution, one being the amount of power the servo used, and two was with system instability (sometimes it would receive a stray signal and trigger the servo). Another problem was there was a second or two delay from when the servo was initially trigger until it closed the switch.
I have looked at a few different wireless transmissions methods such as using a wireless radio modem or something of that sort, but those tend to be rather expensive (a few hundred at least).
We also thought about possible buying a remote locking system for a car and hacking into that to use it for our purposes.
Let me know if you guys have any suggestions for cheap devices we could possibly use.