Triggering alarm when RF transmitter is out of range

Here's a design idea explaining how a 915MHz receiver can sound an alarm when a transmitter moves beyond a predetermined boundary.

The receiver circuit illustrated in this application note sounds an audio alarm when the MAX2623 transmitter moves beyond a designated perimeter. The trigger distance depends on conditions and antenna design. In tests in a home environment with simple wire antennas, the distance was about five feet (1.5m).

View the PDF document for more information.

Originally published by Maxim Integrated Products at www.maxim-ic.com as "Alarm Sounds When RF Transmitter is Out of Range".