12V RELAY Module with LDR

Description

Description

The 12V Relay Module with LDR is a complete, self-contained light-activated switching solution designed specifically for 12V DC systems — including automotive, marine, solar power installations, industrial control panels, and 12V battery-backed applications. Unlike 5V versions that rely on USB or microcontroller power, this module operates directly from 12V power sources, making it ideal for vehicles, boats, RVs, off-grid cabins, and commercial 12V control systems.

The module integrates a photoresistor (LDR) with a powerful 12V relay output on a single compact board. As ambient light levels change, the resistance of the LDR changes proportionally. An onboard LM393 comparator processes this signal against a reference voltage set by the blue potentiometer, providing clean, stable switching without the jitter or noise associated with simple transistor-based circuits.

The module features an SPDT relay (Single Pole Double Throw) with screw terminals for COM (Common), NO (Normally Open), and NC (Normally Closed). The relay contacts are rated for 10A at 250V AC or 30V DC, making it capable of switching most common loads directly — from 12V LED lighting and automotive spotlights to exhaust fans, water pumps, and security alarms.

Key features include a red power indicator LED, a blue relay status LED, an onboard potentiometer for precise sensitivity adjustment, and four mounting holes for secure installation. The module operates directly from a 12V DC power supply (vehicle battery, marine battery, 12V adapter, or solar battery) and requires no microcontroller or programming for basic operation — though it can easily be interfaced with one if more complex logic is needed.

This module is ideal for automatic vehicle lighting, boat navigation light control, security lighting, darkroom equipment, solar-powered garden lighting, daylight-responsive ventilation systems, and any 12V-powered application where light level triggers an action. It is suitable for both hobbyist projects and commercial installations such as signage lighting control, agricultural lighting, and marine equipment automation.

Features

• Designed for 12V DC operation — vehicles, boats, solar systems, industrial 12V panels

• All-in-one design — LDR sensor and relay on a single PCB, no external components required

• Adjustable light sensitivity via onboard blue potentiometer — set any brightness threshold

• LM393 comparator for stable, jitter-free switching

• SPDT relay contacts — COM, NO, NC terminals for flexible load wiring

• High load capacity — 10A at 250V AC or 30V DC, suitable for most 12V loads and AC loads

• Dual LED indicators — Red LED for power, Blue LED for relay status

• Standalone operation — works with just a 12V power supply, no microcontroller needed

• Four mounting holes (3mm) for secure panel or enclosure installation

• Screw terminal blocks for reliable, tool-free wiring

• Automotive-grade compatibility — operates within typical vehicle voltage range (10V–14V)

Technical Parameters