Product Description & Technical Details
Product Description
The Digital LDR Module is an intelligent light-sensing solution that detects the presence and intensity of ambient light. It utilizes a cadmium sulfide (CdS) photoresistor whose resistance decreases as the light intensity increases. This module features an onboard LM393 voltage comparator IC, which provides a clean, stable digital signal (High/Low) based on a user-defined light threshold. It is a fundamental component at Robogears for building dusk-to-dawn switches, solar trackers, and security systems that trigger when a beam of light is broken.
Key Highlights
Dual Output Mode: Provides an Analog Output (A0) for measuring precise light levels and a Digital Output (D0) for simple ON/OFF switching logic.
Onboard Threshold Adjustment: Features a multi-turn potentiometer (trimmer) that allows you to set the exact light level at which the digital pin triggers.
LM393 Comparator: Ensures the digital signal is sharp and jitter-free, even when light levels are changing slowly (e.g., during sunset).
Indicator LEDs: Equipped with two LEDs—one for Power status and another that lights up when the digital threshold is reached.
Compact & Easy to Mount: Small PCB footprint with a dedicated mounting hole makes it easy to install in outdoor enclosures or robotic chassis.
Technical Specifications
Current Consumption: ~15mA
Output Drive Capability: > 15mA (Can directly drive a small relay or buzzer)
Operating Temperature: -20°C to +70°C
Dimensions: 32mm x 14mm
Pin Configuration: * VCC: 3.3V - 5V
Installation Tip from Robogears
The LDR is most sensitive to light coming from directly above its sensing surface. For automatic street light projects, mount the sensor facing the sky but shielded from the lamp it controls to prevent an "oscillating" loop (where the lamp turns on, the sensor sees the lamp's light, and immediately turns it off). In your code, digitalRead(D0) will return LOW when the environment is brighter than the set threshold and HIGH when it is dark.
Note: This product is the LDR Sensor Module ONLY. Jumper wires and microcontrollers are sold separately. Product images are for illustration purposes only.