A laser beam is a man-made invention, as its coherent light does not exist in nature. Make your own laser light pen (or “laser pointer”) from an ordinary flashlight and a few supplies from a laser supply dealer. A few tools from around the house are needed, as is some experience in using a soldering iron.
1. Unscrew the reflector from the front of the flashlight. Poke the lens out of the reflector and throw it in the trash. Unscrew the battery cap from the back of the flashlight and remove the batteries from the battery compartment. Place the cap and batteries aside.
2. Unscrew the incandescent bulb from inside the flashlight with your fingers. Remove the bulb from the flashlight and place it aside. Grip an edge of the bulb socket inside the flashlight with the jaws of a needle-nose pliers. Twist the pliers to dislodge the socket as you pull it out of the flashlight.
3. Place the bulb socket on a work surface with the open end–where the incandescent bulb was earlier–facing up.
4. Unscrew the front section off the laser module assembly and place it aside. Stand the back section of the laser module assembly on the work surface with the holes in the center facing up. Rotate the module so that the two holes that are side-by-side are vertical to each other and the hole to the side of the two holes is at the right side.
5. Grip the laser diode by its base with a tweezers. Insert the shorter of the two pins on the bottom of the diode into the hole that is to the right of the two other holes on the laser module assembly. Insert the other pin on the bottom of the diode into the hole on the assembly that is to the left and above the hole that has just been filled with a pin.
6. Push down on the tip of the diode with the tweezers to seat it in the holes. Place the laser module assembly on its side with the diode facing to the right.
7. Heat up the soldering iron for six minutes. Solder an end of one of the two conductive pins to the contact at the center bottom of the assembly. Let the solder cool for two minutes. Solder an end of the other conductive pin to an edge of the contact that is circling the center contact. Let the solder cool for two minutes.
8. Hold the laser module assembly over the bulb socket with the two conductive pins facing down. Insert the free end of the contact pin soldered to the center contact into the center of the bulb socket. Apply drops of solder into the socket. Hold the assembly steady for two minutes so that the solder can take hold and cool. Solder the end of the other conductive pin on the bottom of the assembly to an edge of the contact that is circling the center of the bulb assembly. Let the solder cool for two minutes.
9. Wrap a strip of electrical tape around the gap between the bulb socket and the laser module assembly. Place the two into the front of the flashlight, bulb socket end first.
10. Screw the reflector back on the flashlight. Return the batteries to the battery compartment and screw the battery cap on. Aim the flashlight at a far wall and depress the “On” button to see a dot of laser light appear on the wall.