**Details** This Tibbit is based on the BH1721FVC ambient light sensor with I2C interface. The sensor is implemented as the [C1 device](http://docs.tibbo.com/phm/tibbit_c1.htm) with a clear (transparent) window. The module measures the light intensity of the surrounding environment and its spectral response is close to that of a human eye. The module outputs ambient light measurements as 16-bit values that do not correspond to any standard measurement units. This C1 device requires the Tibbit #00-3 to be installed in the neighboring ["M" Tibbit socket](http://docs.tibbo.com/phm/the_standard_tibbit_tile.htm). #00-3 provides two direct lines for I2C comms, as well as the ground and +5V power for the BH1721FVC IC. **Sample project** The use of this Tibbit is illustrated by a Tibbo BASIC test project. Yo can find it here: [https://github.com/tibbotech/CA-Test-Tibbit-28](https://github.com/tibbotech/CA-Test-Tibbit-28).