Laser Diode Module


KY-008 laser LED module has three pins, as shown in Fig. 1. The pins are labelled (from left to right) as: pin 1 as S, pin 2 (centre) with no label and pin 3 with – (minus sign). Pin 2 outputs the exact same voltage as the supply voltage, which is connected at pin 1. Pin 2 can be used in the following ways:

  1. To monitor incoming power supply or voltage level.
  2. To use as triggering input to alarm circuit when voltage at pin 2 drops (such as when someone cuts the power supply of laser LED, or when voltage drops below an acceptable level for an application). In short, this module provides an option to monitor its own power supply.

When you connect a 5V power supply to the laser module, a red-dot laser beam appears.

This 100mW laser module emits a small intense focused beam of visible red light. The module can be used with an Arduino and photo resistor module to perform basic remote signaling.

Warning: This is a low power laser device, however as with all laser devices care should be taken when in use. You should never look directly in to its beam or point the laser at another person. Doing so may cause permanent eye damage. This item is not suitable for children.


Input voltage: 5V DC

Input current: 30mA

Wavelength: 650nm


Interfacing with Arduino:

Diagram above shows the Laser Diode Module pinouts, which contains Signal (labeled as S), GND (labeled as -) and the middle pin indicates +5V. The connection between Laser Diode Module and Arduino Uno is described in detailed way as below:

Signal -> Pin 8


+5V -> 5V


#define LaserPin 8

void setup ()


   pinMode (LaserPin, OUTPUT);


void loop () {

   digitalWrite (LaserPin, HIGH);

   delay (1000);

   digitalWrite (LaserPin, LOW);

   delay (1000);



Laser technology must have a various application fields, in almost any of the science field you may observe laser technology applications and devices. In the following I mention the applications of such technology as far as I encountered, observed, used, or read about:


  • Computer devices such as laser mouse, laser presentation, CD ROMs and DVD ROMs
  • Astronomy and communication applications
  • Medicine, surgery, and health
  • War machines, guns and tanks
  • Cutting matters in metallurgy industry and related industries
  • Robotics, especially in image processing and calculating distances
  • Toys