Bobcat
Use the included pin to press and hold(6-10 seconds) the rear BT button until the led light on the top turns blue.
Syncrobit
Unplug and replug the unit, the lights will turn blue in the corner. This will enabled bluetooth for 5 minutes.
Sensecap
Press and hold the rear button until the blue led starts to flash slowly.
Nebra Indoor
Push the button on the rear once to enable bluetooth.