LDR Light Sensor Module with Day/Night Invert Logic | CompoDen
LDR Light Sensor Module with Day/Night Invert Logic – Digital Output, Adjustable Threshold
The LDR Light Sensor Module with Day/Night Invert Logic is a digital light detection module using an onboard comparator to provide a clean HIGH/LOW signal based on ambient light levels. Ideal for automatic lighting, security systems, and robotics, it features an adjustable sensitivity potentiometer and a jumper to invert the output logic, making it versatile for both light-activated and dark-activated circuits. The module operates at 3.3V–5V and outputs a TTL-compatible signal directly to microcontrollers.
Key Specifications
| Specification | Value |
|---|---|
| Operating Voltage | 3.3V to 5V DC |
| Comparator IC | LM393 |
| Output Signal | Digital (TTL compatible); sink current 15mA |
| Sensitivity Adjustment | Onboard potentiometer (100K) |
| Logic Inversion | Jumper to select light-on or dark-on mode |
| Board Size | 32 mm x 14 mm |
What You Can Build With This
- Automatic porch light that switches on at dusk using a relay module.
- Darkness-activated LED strip for staircases or cabinets.
- Line-following robot with ambient light sensing for course adjustments.
- Sunrise alarm clock that triggers a buzzer when ambient light increases.
Compatibility
This module works with any microcontroller that has a digital input pin, including Arduino Uno, Nano, Mega, ESP8266, ESP32, and Raspberry Pi (with appropriate level shifting for 3.3V logic). Connect the DO pin directly to a digital I/O. The output is push-pull with onboard pull-up, so no external resistors are needed. Common pairings include relay modules, motor drivers, and LED strips.
Wiring Notes
Connect VCC to 3.3V or 5V on your board, GND to ground, and DO to a digital input pin. The module includes a power LED and an output indicator LED. When using with inductive loads like relays, add a flyback diode and a transistor driver if the relay coil current exceeds the module’s 15mA sink capacity. No additional pull-up is required.
Why Buy from Compoden
Every component is sourced from verified suppliers and tested for compatibility before listing. We've spent 10 years building projects for makers, schools, and institutions across India. Ships from Bengaluru in 3-5 days. If defective on arrival, replace within 7 days.
Is this compatible with Arduino Uno?
Yes, the module works directly with the Arduino Uno at 5V logic. Connect VCC to 5V, GND to GND, and DO to any digital pin (e.g., pin 2) and read its state with digitalRead().
How do I invert the output logic?
The board has a 2-pin jumper header. Place the jumper on the pins marked L to get HIGH when light is above the threshold (light-on). Move it to pins marked D for HIGH when dark (dark-on).
What is the detection range?
The sensitivity potentiometer adjusts the threshold from a few lux (dim light) to direct sunlight. Turn it clockwise for higher light thresholds. The onboard LDR responds across a wide spectrum.
📦 Free Setup Handoff Document Included
Every Compoden order includes a free setup handoff document — step-by-step instructions to get your component working within minutes. Download it via QR code on your package. The handoff document is also trained to help you troubleshoot the majority of problems.
Ask Soldr above what you can build with this — it knows every Compoden kit this part appears in.
Shipping Information
- Prepaid Orders: ₹75 for orders up to ₹999, FREE shipping above ₹999
- COD Orders: ₹125 shipping + ₹50 COD fee = ₹175 total
- Delivery Timeline: Dispatch in 1-2 days, delivery in 2-7 days depending on location
Returns & Warranty
- 7-Day Return: Manufacturing defects only (approval required)
- Warranty: 7 days from delivery
- Non-Returnable: Batteries, consumables, cut wires, clearance items