Hi:
I am trying to find or design a circuit that would transmit a carrier wave (at any fixed audio frequency) radio signal on the AM or FM band only a few inches (anywhere from 2 to 12 inches). The AM or FM frequency must be able to be changed across the band by changing a resistor, capacitor or ? It also needs to as small and simple as possible. Audio quality isn't important. Audio frequency it transmits isn't important.
What I am trying to do is something like RFID they are using in inventory control, except mine must transmit less than 12 inches and just transmit a carrier wave at a fixed audio frequency. Since I have less than 16 objects I have to identify, I planned to tune each of the
16 units to a different AM or FM frequency. Then I could identify which of the 16 units I had based on the frequency.I am also open to other ideas that would accomplish the same thing. I am trying to keep the costs low, so I didn't think standard RFID equipment would be an option.
If you have any suggestions, even just a word or two of sdvice, it would be greatly appreciated.
Thanks a lot,
Joe G. Reno, PA
my email is: ru4him at gmail dot com