System 3000 brightness and temperature sensor BT Features: Sensor for recording brightness and temperature. Operation with the System 3000 blind timer and timer BT, operating top unit BT and room temperature controller BT. Transmits the current brightness and temperature value via Bluetooth(r). Expansion of functions for the System 3000 blind timer and timer BT, operating top unit BT: Sun protection function, dawn and dusk function. Is used as an external temperature sensor for room temperature control. Battery-operated device.