My goal is to find a way to determine which device is in which user’s hand and know when it switches hands.
The device will always be back to the user’s chest and the user is already wearing a belt with the device that was previously wired.
People work close together at times and I want to make sure the device doesn’t “switch hands” accidentally.
I am thinking a directional RF transmitter with a range of maybe 18" (half a meter). The belt would need to transmit a 16-bit ID every second or so.
How can I accomplish this? Would this be reliable?