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RGB Projector II

This was a quick project to build a 'test bed' RGB laser projector that I could use to evaluate different laser diodes, galvo scanners, etc. In order to make it easy to modify I decided to use the classic 'optical breadboard' construction technique so that I could easily swap components in and out as needed. The projector currently has multimode 640nm, 515nm and 445nm laser diodes mounted in it, and does about 2W of whitelight which is great for small beamshows and compliments my 3D printed RGB laser nicely.

Overview:

I started with a 12" square breadboard (tapped with 1/4-20 holes on 1" centers) and some thorlabs kinematic mounts that I got on ebay, and decided to machine the rest of the components myself since even on ebay the prices for the clamps and posts was absurd. I did the machining and general construction at MITERS over the course of a few weekends. Here are some shots of machining the pedestal posts from some 1.25" aluminum round stock. The second picture is me relieving the bottom so that it sits flat on the optical table. I also tapped the bottom with a 1/4-20 thread so it can be directly screwed into to breadboard, and tapped the top to 8-32 to allow a mirror mount to be screwed into it. Finally I drilled a cross hole through the post on a mill so you could slide a screwdriver through the post to keep it from turning when tightening.

I made the table clamps from some 1.5x0.25" aluminum bar stock on the mill, just a slot through the clamp to allow it to be screwed to the breadboard and a notch on on corner so it can clamp the foot of the post. And the pile of chips at the end of it all.

And here is a shot of the projector after I was done machining all of the optical components, and it being stored in MITERS next to my box-o-cruft and a very sad cherry cokinator tesla coil.

Here is a shot of the wiring and my DAC. I used a set of FlexMod P3 laser drivers and a set of scanners I got on ebay for about $40 (they are terrible for graphics, but work fine for beamshows). For the DAC I built a sound card DAC inspired by the LaserBoy project along with the EzAudioDac drivers so that it works with LFI Player. For the USB sound card I took apart a cheap pair of USB 'surround sound' headphones I found in the trash and extracted the 5.1 channel sound card out of the USB connector. It turned out to be based on a c-media chipset that is not supported for anything newer than windows XP, which is probably why it was thrown out. I soldered some wires to the DC blocking caps to get the DC coupled audio signals out of it, and then used some quad opamps on a piece of perfboard to offset/scale these to match ILDA levels needed for my laser and scanner drivers. In retrospect I wish that I had added an ILDA compatible DB25 connector on the board so that I could use a more modern DAC, since now I am forever stuck using this projector with windows XP if I want to be able to use windows based laser software (like LFI Player). I have been wanting to get into linux based laser shows, but sadly it seems the overwhelming majority of laser software is windows only. I did try messing with LaserBoy a bit, but found that the lack of a live output really ruined for fun of laser scanning for me. I have been meaning to try out the OpenLase project but when I tried running it (in 2013) I couldn't figure out how to make it actually do anything useful. More recently I have been using the free version of LAsershowGen which has been quite nice now that it supports real time scanning, and despite the fact that it is not Free (as in freedom) it is open source which is a nice change of pace since the majority of laser software I have come across has been fully closed.

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I can be contacted at contact@krazerlasers.com