Gonzo, one thing I feel I must add, you are controlling a piece of machinery via a radio link using what I assume will be a "free for all" frequency.
You need to ensure that none of the kiddy toys which vomit all over the RF spectrum can start the thing when you dont expect it.
Something a bit more rigorous than the presence of a signal is required to start the machine, and it should stop on failure of the control signal.
Just my 2 cents worth, (or should that be 2dB worth?).
JimB