The BH1750 is a digital ambient light sensor that measures light intensity in lux (Lx). It's a small, inexpensive sensor that can be used in projects to detect and measure light. The BH1750 has a 16-bit light measurement range of 0–65,535 lux, and with some calibration and adjustment, it can measure up to 100,000 lux. The sensor uses an I2C interface to communicate and has a built-in 16-bit AD converter. It's also close to the spectral characteristics of human vision, making it ideal for high precision measurements.