FM Transmitter

Hi, I am looking to build from scratch/buy/build from kit, a set of FM transmitters. In our company we have a manual assembly area where small assemblies are done by people. We would like to have the person press a button after each part is complete. This signal would be transmitted to a receiver and give a dry contact closure to an ethernet line. This ethernet signal is then interpeted by our real time software. By doing this we can see how many parts are complete, average cycle time, job time remaining, etc.

The big problem with all the kits and modules I have looked at, is they are all on the same frequency. I see you can get BCD kits to ID individual xmitters. This won't work becasue two people can try to transmit at the same time. They had an earlier system that had this problem. I have looked at kits at Ramsey and Glolab.com and don't see an answer. Any help or ideas would be appreciated. I would also build a simple xmitter an receiver from scratch if anyone had a idea. We need a range of at least 200' indoors.

You want to build a Chrismitter or a Transmitter?

Perhaps something from this company **broken link removed** would work.

Don't know that there are any kits available that will do what you need, especially to 200'.

Thanks for the link, that is exactly what I am looking for!