Where are you located? If in the USofA, and you want to do this, you need to contact the FCC. You are not permitted to broadcast control signals without a license. Garage door openers, keyless entry, cordless phones, wifi, all have power and band limits.
There might be certain radio control products such as model airplanes that might be adapted for your needs, but you are not permitted to modify the output in any way.
If you inadvertently interfere with a legitimate licensed user, the penalties are quite onerous.