The World's Fastest Laser Projector
Hi folks!
Please forgive the title and try not to look for a technical exception (I'm looking at you, Steve!), but I wanted to share a project that I worked on for Sal (DiscotheFunkyHippo) that took up a good deal my time this past year. For those of you who attended the SELEM presentation by the same name, this is just a post covering the majority of the same material I shared then.
OK, so the not-so-short story is Sal approached me at SELEM 2018 with a request to build him one heck of a cool projector based on the single-mode based designs that I build for myself and a few friends. His primary request was a highly capable and highly flexible laser projector for use in a 'studio environment' for content creation. This content would then be reproduced using several rental more powerful multi-mode projectors as required. Specific requirements after several discussions included:
- Four sub-projectors in a single case
- High-quality galvos
- ~1W single-mode beams with well-balanced whites
- Glow in the dark (405nm) drawing capability
- Lumia/Scan-through effect capabilities
- Lightweight and portable
- Delivery time frame 6-9 months
I tend to work backwards with my builds; procuring a case that I think will barely fit the necessary components and then jamming everything in. I hoped to design this case from scratch in Fusion 360 as Adam Raugh (ARaugh) had just taught a course on the topic during the same SELEM. A combination of inexperience and laziness resulted in me buying a case (Case D) from Goldenstar for about US$720 including shipping. This case is well designed and intended to be a typical double decker with a sealed optics deck up top and an actively cooled PSU deck below.
This case is 339mm (13.34") x 244mm (9.6") x 376mm (14.8") and weighs approximately 13.6KG (30lbs). OK, that pretty much killed the "lightweight and portable" requirement, but it was the best I could do. This said, the case was well thought out and built like a tank. This projector was designed to place two builds on one optics deck and another two on a separate deck. The case had a steel plate separating the PSU deck, so I replaced that with a thicker (0.3125") 6061 alum plate adding another US$120 to the case cost. After cutting the edges of the new plate a little too much, I ate that $120 and repeated the process more carefully. No worries, though as I'll use that for future projects.
OK, that solved, I was off gathering parts. Initially we planned on having four sets of C-506's with MachDSPs in the projector, but one thing lead to another and we ended up ordering four sets of Saturn 1s. "Damn the budget, full speed ahead!" was kinda the theme for this build . . .
I've built lots of similar single projectors to date, so the rest of the parts were pretty much a given. Twenty-eight SimpleDrive diode drivers from BBE, colimation lenses and laser diodes from DTR, PBS cubes and dichros from six different suppliers (Lasershowparts, Opt Laser, Edmund Optics, etc.), safety boards for future variance compliance from Stanwax, Lasorbs from Pangolin, etc., etc.
There were a couple minor hick-ups as the build went through for minor stuff like fan speed controllers and such, but nothing too big a deal.
The missing (5th element) was a custom lumia wheel approach. I had originally considered using the LK-PD3 DMX lumia controllers as that's one of the few options that allow us to switch between 7 effects + one open slot and rotate each of the 7 effects. I purchased two of the LK-PD3s for this purpose, but after some conversations with my brilliant friend Ed (ekeefe), we decided that we could design and he could build a much more robust controller for the wheels that came with the LK-PD3s. For those of you keeping score at home, that resulted in essentially throwing away almost the entirety of two new LK-PD3s. Well, one got rebuild into an analog RGB rig for another laserist, but you get the idea.
So six months of going back and forth on design changes and prototypes occurred while I built the top deck which is 2 x 1.1W RGB + my custom Glow In The Dark (~1.5W) setups. I won't go into too much detail here as I intend this to be detailed in a different thread, but Ed created two versions of a DMX / manually controlled lumia / scan-through solution dubbed the Scan-Through Rotator.
As you can see, one of these uses a high quality geared DC motor to rotate the scan through effects and is great for traditional 'shower-glass' lumia which needs to be rotated very smoothly and generally slow. The DC motor version that went into this projector has 5 DMX channels and manual mode with 6 shower-glass elements plus one star lens plus one open slot and can rotate the effects from 0.45 to 3.33RPM. The other lumia wheel had 7 scan-through effects like burst, lenticular and other such effects and uses a stepper motor to rotate the individual effects. This two stepper-motor version has 8 DMX channels (and ability to control everything manually) in addition to fantastic micro-stepping capabilities, albeit isn't quite as smooth as a DC motor at slow speeds. Right tool for the right job and all that . .
I LOVE these Scan-Through Rotators and am upgrading several of my projectors to incorporate them. More on this front soon.
In the interest of keeping this short, a full year after the initial request, Sal had a projector that had:
- 2 RGB builds with Glow In the Dark (GITD) capabilies (DMX or manual switching). Typical of my GITD builds, you can draw tight 405nm beams or soft fill 405nm beams)
- 2 RGB builds with Lumia/Scan-through capability (DMX or manual control). The RGB single-mode diodes have a combination of colimation lenses that allow for nearly identical beam overlap with quite low divergence. The RGB beams measure 5mm x 5mm at a distance of 25 meters (82 feet).
- With the Saturn 1's, all four heads can scan at speeds up to 90kpps. (Imagine what you could draw with distributed scanning of 360k points per second?)
- Every single diode begins lasing lovely single-mode beams at 0.1V at levels matching the other three projectors. With the diodes used, this resulted in matching gray levels that start at 4mw and go up to over 1W. (BBE's drivers are awesome!)
- For safety, all four projectors individually kill power to the diode mains and clamp down the modulation unless all of the requirements are met (ILDA signal, key-switch, and E-stop) The key and E-Stop are shared among all four projectors, of course.
- A single enclosure weighing in at a "svelte" 69.9lbs. Not exactly light and portable, but still a heck of a lot lighter than 4 Plutos.
I think that's about it. I had precious little time to play with this beauty after testing before turning it over to Sal, so he'll have to post some amazing content in the coming months. I will leave you with a few photos that I got before it left my bench:
More pictures are available here for a limited time.
Thanks to Ed for his expertise and ideas that made the Scan-Through Rotator a reality. Also a big thanks to Sal for his faith to put forward the big $$$ in required to create this build - especially as I am just an amateur custom projector builder. It was a fun (and exhausting) project!
-David
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Originally Posted by mixedgas
