LDR Ambient Light Sensor Module, 3.3V–5V, 4-Pin

This photosensitive LDR ambient light sensor module detects environmental light levels and provides both analogue and digital switching outputs. Operating between 3.3V and 5V, it can trigger microcontrollers or directly switch relays when light thresholds are reached. It is an accessible choice for students, hobbyists, and makers building light-activated projects.

Ambient light detection

The module utilises a sensitive photosensitive resistor to monitor changes in surrounding brightness. It is designed to evaluate ambient illumination for environment-monitoring tasks.

Digital switching output

The DO pin provides a TTL switching signal that outputs high when ambient light is below the set threshold and transitions low when light intensity exceeds the threshold. This output connects directly to single-chip microcontrollers to detect high and low level changes.

Direct relay operation

The output can directly drive a relay module, enabling the creation of standalone light-operated switches.

Power and pin connections

The 4-pin board operates with an input power supply between 3.3V and 5V on VCC, ground on GND, and supplies a TTL digital output alongside analogue output capability.