Doorbell technology....

Hi

Can anyone help me with any suggestions to the following, im looking for the smallest transmitter and equally the smallest receiver i want to be able to at least set thirty different channels and emit a tone, with a distance of 3 feet.

I would be very gratefull if someone could tell me what i would actually need instead of directing me to a website.

Thanks in advance Geepster

The easiest way is to use a discarded TV receiver with a remote control. It can send >30 different commands, and its range is ~10 meters, infrared.