Nuts and Volts - May/June 2018

everything is off. I put a pass-green/reflect-red mirror at a

45 degree angle with the green beam going through the middle. I marked the holes, then drilled and screwed the mirror bracket to the mounting board. The red laser is mounted so that it aims at the mirror.

Now, the adjustment screws can aim the red laser at the spot where the green laser goes through, and then the mirror’s adjustment screws can be used to line up the dots projected on the wall or paper. The beam’s spots on the mirrors are difficult to see at this low intensity, so I didn’t wear the safety glasses for this.

As mentioned, extra caution should be exercised for where the beams will hit so that they don’t make contact with a shiny surface. With everything screwed down, careful placement will have the beams directed down where they won’t hit anyone’s eyes.

Once you’re sure a beam can’t bounce directly into an eye, there is a slightly brighter setting that will help to see it better. Breathing on the mirror will fog it up and allow you to see where the beam is hitting. I placed the blue-reflect mirror in the same manner. All three beams are now aligned.

Once the glass disks are fastened onto the motors, a cover (Figure 8) should be in place so that everything inside is shielded from view.

A final focusing and aligning of the mirrors can be done while looking at the patterns on the wall. After the beams were aligned in the mirrors, alignment adjustments are made only with the mirrors, and not the lasers. Focusing the laser on the glass disk is different from focusing at a distance. The intensity is set at dim with all lasers on (Program 13). A cover over only the glass disks protects your eyes from what bounces off the back of the disk.

A laser test circuit (Figure 9) was made to get some of the details ironed out on how the lasers worked. It’s not essential for this project, This circuit is shown near the main circuit in Figure