Abstract A calibration concept of an analog light-sensor for the use in a dark ambience is presented in this paper. The aim is the automatic detection of an upper and lower sensitivity limit to use the system in combination with a Wireless- Sensor-Node  as an impulse generator for industrial strobe beacons. For optimal measuring ranges the gain of the sensor is variable and allows adapted sensor resolutions. A calibration process is presented which focuses on the upper light limit and calculates the lower limit depending on gain and user parameters. A measuring accuracy of around 0.43 lx and a standard deviation of 0.42 lx are achieved. The resolution of the sensor depends on the measuring range and is up to 0.05 lx. An experimental setup shows performances within a specific scenario.