A proximity alert device may include a processor, non-volatile memory, a user input device, a radio transceiver, and primary memory that stores program instructions. When executed by the processor, the program instructions may perform a method that includes loading a configuration value from the non-volatile memory and setting a transmission power level of the radio transceiver to a configuration power level; pairing with a protected device that has a corresponding radio transceiver; receiving input from the user input device to adjust the transmission power level up or down; in response to receiving the input, and based upon that input, adjusting the transmission power level up or down, and saving to the non-volatile memory the adjusted transmission power level as a calibrated power level; detecting a loss of connection with the paired protected device; and, in response to detecting the loss of connection, triggering an alarm.