Connect the laser diode module to Arduino pins the right way. Signal goes to a digital output pin. Write easy Arduino code to turn the laser on and off. Test your circuit with care before. However, the guidelines and tips outlined in this tutorial will supply the information necessary to plan a proper system that will supply stable operation over long diode lifetimes. Application is going to. They typically have three input pins: VCC (power supply), GND (ground), and SIG (signal). Other modules include only two pins: VCC (power supply) and GND. This circuit uses an Arduino Mega 2560 to control multiple laser diodes and read inputs from several photocells (LDRs) through analog pins. Unlike LED light, a laser's light output is more concentrated, meaning it has a smaller and more narrow viewing angle.