Transmitter/Receiver Project

I’m not an electrical engineer and need some help with a small project in which four transmitters send four different signals to a small receptor across a distance of maybe 15 or 20 feet. The transmitters need to be quite small, or at least thin, maybe 3/8’‘s of an inch thick and no more than 3/4’’ by 3/4’'. The receiver can be much bigger, but preferably no bigger than an old cellphone.

Essentially I need to know when the transmitters are moved (it doesn’t need to be super sensitive, but such that when each transmitter is lifted, it signals the receiver) and the signal for each transmitter must be different (such as the receiver vibrating once, twice, thrice or four times depending on which transmitter is moved). Given this set up, I imagine the transmitters can be activated (sorry for my naiveté, that’s probably not the right word) using an infrared system, motion sensitive system, or maybe most simply, a magnetic system (i.e, when the transmitter is moved from a magnetic plate, it transmits a signal to the receiver).

Any thoughts on where I might procure the necessary materials for such a project, and how to set it up?

Thank you very much for the help.

Feel free to email magicmav@hotmail.com, if you have advice and feel particularly generous with your time.

You will most likely need antennas on both the receiver and the transmitters for that range, and it is very difficult to accommodate one in a 3/4 x 3/4 inch PCB. It might be possible with 2.4 or 5 GHz modules.

This would be much easier if you could relax the size requirements. The common 418MHz transmitters are about 1.5" long if I remember correctly and they work pretty well over that distance. Now, it’s certainly possible to hand build much smaller transmitters, but that’s a bigger project involving serious design work.

You may find info regarding a working RF link here:

http://magusporta.com/projects/rf_manch … ster1.html

Regards,

Marcelo