A portable proximity alarm apparatus comprising a
Bluetooth system and an alarm monitors the presence of a portable electronic device equipped with a compatible
transceiver within range and alarms when that device leaves its range. On detecting disconnection, the proximity alarm automatically tries to reconnect. A portable proximity alarm apparatus with an optional voice mode allows for listening to a monitored device and / or to send voice to a monitored device. A proximity
alarm device particularly suitable for monitoring persons and animals comprises a base device having a
Bluetooth transceiver that can pair with a monitored device having a
Bluetooth transceiver. The base device has a lower frequency
receiver and the monitored device has a lower frequency
transmitter, optionally the base has a lower frequency
transmitter and the monitored device has a lower frequency
receiver. The lower frequency is less than 1 GHz and preferably 433 MHz. The lower frequency
transmitter and receivers are activated when the base and monitored devices are paired and the Bluetooth transceivers enter a sleep or low
power usage mode, such as sniff, park, and hold. In an embodiment, the lower frequency transmitter and / or
receiver has an adjustable range.