Cheap laser projector

Assembling a Projector

Let's start collecting the “heart” of our projector - the side of the beam sweep. To do this, we need to cut an “L” shaped stand for stepper motors from aluminum sheet (it can be tin) with metal shears. Drill a hole and install stepper motors. Stepper motors must be strictly perpendicular but displaced in height.
Cheap laser projectorCheap Laser ProjectorCheap Laser ProjectorCheap Laser ProjectorCheap Laser ProjectorCheap laser projector

Making mirrors.

To make mirror elements we need to take a disk from a broken hard disk. Why not a simple mirror? - you ask. A simple mirror will not work, since it is mirrored only on one side, and as you probably remember, the mirrors in the projector are spinning in a circle.Ordinary laser discs can be used, but they do not reflect as well and some of the brightness will be lost on them. The hard disk drive needs to be cut, better by a grinder. The resulting mirrors are glued with hot glue to stepper motors. Cheap Laser Projector

Electronics

The projector is controlled by Arduino Uno plus the stepper motor driver of the same firm. Control is exercised through bluetooth, but you can also directly through the uart adapter. I think you shouldn’t explain how to connect those who have ever worked with Arduino, and I don’t see any sense for those who didn’t work. The laser diode also feeds through the Arduino with brightness control. Additionally, I will show where the photo diode is connected. This photo diode is needed for the initial calibration of the projector. It is installed perpendicular to the upper engine, pay attention to the hole above the lower engine.
Cheap laser projector
Cheap laser projector
Cheap laser projector
Cheap laser projector

Calibration

After you have collected everything you have debugged, you need to calibrate the projector.To do this, we will use a photodiode placed in a hole on the central axis directly above the stepper motor of the X axis. To obtain more accurate measurements, a circuit with a variable resistor was required. When calibrating, we read the values ​​from the photodiode, and when the value exceeds a certain value (the laser directly shines into it), the motors stop and return to their original position. Code, calibration program. pseudo code for calibration // 1step = 0.9 ° / 400steps = 360 ° = full rotation laserOn (); for (int a = 0; a <=400; a ++) { for (int b = 0; b <=400; b ++) { photodiodeValue = readValue (); if (photodiodeValue > = photodiodeThreshold) { laserOff (); returnHome (); } stepY (1,1); } stepX (1,1); } laserOff (); unsuccessfull ();

Final Assembly

The entire projector was placed in a plastic junction box and tightened with screws. The projector turned out to be portable, just plug in the power supply, switch the switch, and you have your laser show.
Cheap laser projector
Cheap Laser Projector


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