You can learn to connect and program a laser diode with Arduino in this tutorial. A laser diode makes a narrow beam of light. This is helpful for finding objects or lining things up in electronics projects. The steps in this tutorial are simple, so beginners can do them. Safety is. A laser diode is a cool component that you can do a lot of fun stuff with, from engraving wood to creating a light show or giving your robot eyes! They range from super cheap (or even free if you can find one in an old CD player!) to more expensive. The solar panel charges a 18650 battery via a TP4056 charging module, and a push button controls the activation of the laser emitter and the LED through a MOSFET switch.