Help measuring distance between two boards of education

trinzul

I'm having some difficulty coming up with a solution for measuring distance between two boards of education. Here is the basic idea of what I'm looking for. I want to place one board in a stationary location and carry the other board with me. When I get a certain distance away from the stationary board I want the board I'm carrying to alert me.

I'm looking for suggestions for how to know when the one board has crossed the distance threshold. I've been thinking RF Transceiver and measuring RSSI, but it looks like that may be a little unreliable for what I'm attempting. I suppose GPS could also be an option. Anyone attempt anything like this or have a suggestion that would work.

graffix

What kind of distance? Is it indoors,line of sight?Gps tends to be accurate within 3-5ft and works better with fast moving objects.

trinzul

There would probably not be line of sight. Let's say one board is placed outside in a car sitting in my driveway. I carry the second board with me as I exit the car and enter the house. I'd like for that to be the distance threshold to alert me that I've gotten too far away from the board in my car.

Franklin

What kind of distance and how accurate does it need to be?

trinzul

Not looking for a huge amount of accuracy. If one board got 20ft away, it would be fine to have a plus or minus 5ft around that. Doesn't need to be an exact position either, just 20ft in any direction.

erco

One of those child monitors that sounds an alarm if the kid strays too far. Probably based on RF signal strength.