Introduction: IR Illuminator (Infrared) Part-1


In this instructable, we will learn a little bit about Night Vision, different ways to achieve night vision and a simple IR Illuminator Circuit to aid the night vision of CCTV Cameras.

The above figure shows the Circuit diagram of IR Illuminator Night Vision, as the name
suggests, is the ability to see at night i.e. at low-light. As humans lack (or have very poor) night vision, we make use of technological ways i.e. cameras with special features. Although developed for military usage, the night vision technology, and the corresponding equipment are becoming easily available to normal public use.

The Night Vision technology, as a part of Enhanced Vision Systems, is a part of the aircraft security system, which aids the pilot in surrounding awareness to avoid crashes.

Modern-day automobiles (mostly in high-end cars) are fitted with Automotive Night Vision system, which helps the drivers to see better in dark or poor lighting conditions.

Step 1: Required Hardware

The following components have been used:

· 12V Power Supply

· 30 IR LEDs (5mm)

· 6 x 330Ω Resistors (1/4 Watt)

· 3 x 2N2222 NPN Transistors

· 12V Relay

· 100KΩ Potentiometer


· 1KΩ Resistor

· 10KΩ Resistor

· 1N4007 Diode

Step 2: Circuit Schematic & Working

The above image shows the Circuit Schematic IR Illuminator.


The circuit can be divided into three parts: the light sensor, the relay driver and the IR Illuminator. The combination of 100KΩ Potentiometer and LDR act as a potential divider and along with the Darlington Pair, they help in sensing the ambient light.

As the intensity of light falling on the LDR decreases, its resistance changes and the relay gets activated with the help of its driving transistor.

When the relay gets activated, the IR LEDs get a path to the ground and start to glow. The 100KΩ POT can be used to adjust the sensitivity of the lighting conditions.

Coming to the IR LEDs, they are 5mm Infrared LEDs with a forward voltage of 1.2V and a forward current of 20mA. A series of 5 IR LEDs are connected with a current limiting 330Ω resistor.

Six such combinations are connected in parallel to form an IR Illuminator array of 30 LEDs. You can easily add more LEDs but make sure that the power supply has enough juice to provide sufficient current.

Step 3: Advantages of IR Illumination

  • When used in night vision, they provide good sensitivity and are not easily affected by ambient light.
  • They are considerably inexpensive.
  • If IR LEDs are used as IR Illuminators in night vision, they provide a reliable option with low power consumption, good longevity and rugged usage.

Step 4: PCB Design

The above figure shows the PCB design of IR Illuminator using Eagle software.

Parameter consideration for PCB design:

1. Trace width thickness is minimum 8 mil.

2. The gap between plane copper and copper trace is a minimum of 8 mil.

3. The gap between trace to trace is a minimum of 8 mil.

4. Minimum drill size is 0.4 mm

5. All the tracks which have current path need thicker traces.

Step 5: PCB Fabrication

You can draw the PCB Schematic with any software as per your convenience. Here I have my own design and Gerber file. After you generate the Gerber file you can send it for fabrication.

As is always say, I prefer LionCircuits for my PCB fabrication needs. They have the best prices and a very user-friendly platform. I just upload the Gerber files and place the order online, they take care of the rest.

I will write the Part-2 of this instructable soon. STAY TUNED!