Aligning the beam took a bit of time as aligning all three horizontally and vertically first required that the beams were straight. tested each laser beams vertical height and horizontal shift with a ruler. 

Then incident that beam on to the galvanomirror and tried to centre the beams again by making sure that all the beams were almost incident on the same point at one of the mirrors of the galvo. 

This alignment would have been way easier if done with individual dichroic mirrors.

I then proceeded to implement the algorithm of raster scanning with a single beam at constant voltage, and then with three beams at constant voltage (not PWM) I got a bright white light that had a bit of a blueish hue to it because of the much higher intensity of the blue and green laser compared to the red which was almost hidden in the resultant light. 

This is how my setup looked with everything working.. I chose to put a aperture to limit the beam width  right in front of galvo which was a bad idea.. i then moved it post galvo for better results. 

with the algorithm working i projected a rectangle and a circle on the screen and these were the results. 

rectangle with RGB white light (blueish hue)

and a circle. 

We can see a clipping at the bottom i'm not sure why that is.. will test more.. 

The idea that we can project any shape to it is a proof that we can project anything onto it using the bitmap methodology. and with this i conclude the demonstration part of my project. I'll still be working on making it better and will try to project a complete image or a  5 second video on it, but that will take some time. 

This was all done as part of my final year project at "CMND: centre for micro and nano devices" facility at COMSATS, Islamabad by me (Shoaib Mustafa) under the supervision of my supervisor: Dr. Mujtaba Hussain, mujtaba.hussain@comsats.edu.pk

feel free to reach out at shoaib.mustafa7@hotmail.com

follow my youtube:

 https://www.youtube.com/@capistor1 for more details and following videos.

here is the github where i'll be uploading all the material. https://github.com/manhoosbilli1/Laser_Projector

I hope you had fun!