Help me create a pre-set proximity detection system

Hello,

I am very new at this and I would like to create a system that would detect a pre-set proximity between 2 objects between 0 and 50 meters. I have seen a similar card using a RFM3000 hybird transceiver. I am looking for a company of other source to find a schematic and help.

Thanks alot,

Donald West
info@mds-safety.com