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Step 5Build the laser part
Then solder the photodiode circuit on a small piece of perfboard, test if outputs are high without light and low when you shine a laser on it. You can adjust this with the pots.
Modify the 3 Laserpointers so they can be hooked on the 9V. I put 300 Ohm Resistors on them, they run on 2x 3V Button cells normally, now they are not quite as bright as before but enough to function. I had no other resistors around and was too lazy to calculate it. That will vary with the type of laserpointer you use.
Glue the pcb in place. The laserpointers must hit the photodiodes exactly at the right spot. I used hot glue for them and held it in place until it cooled down (with power on and always aiming at the photodiode). Maybe there is a better method that also looks better. I had to adjust it later by bending the leads of the photodiode which looks even worse.
Modify the 3 Laserpointers so they can be hooked on the 9V. I put 300 Ohm Resistors on them, they run on 2x 3V Button cells normally, now they are not quite as bright as before but enough to function. I had no other resistors around and was too lazy to calculate it. That will vary with the type of laserpointer you use.
Glue the pcb in place. The laserpointers must hit the photodiodes exactly at the right spot. I used hot glue for them and held it in place until it cooled down (with power on and always aiming at the photodiode). Maybe there is a better method that also looks better. I had to adjust it later by bending the leads of the photodiode which looks even worse.
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