buffo
Excellent question! It will depend largely on the diode and lens selected for the build. I think Mike is leaning towards the long open can reds, but as to which lens he ends up using - that's still up in the air. There is a trade-off between cheap lenses at the start (which yield fatter beams that are easier to overlap, at the cost of a larger overall beam), verses expensive ones that yield superior beam quality but add significant costs (up to 3X the cost of the diodes) and also make the "knife-edge" alignment absolutely crucial...Originally Posted by Laserman532
If I were attempting this project myself, I'd probably invest in a set of motor mount shims. (The ones they use to align a large industrial motor to a pump, for example.) They come in standard widths - like .1 mm, .2 mm, .5 mm, 1 mm, 2 mm, 5mm, etc... You just stack up enough of the ones you need. They are "U" shaped and usually run around 2 inches square. You could even cut them to size using a dremel tool, so one shim could be cut down and used for several mounts...
I actually tried using large fender washers (to get around the "leaning tower of pisa" problem) on a little project (not laser-related) I was working on about a year ago. And what I discovered was that the thickness of your average fender washer varies quite a bit from one washer to the next. So you would need to do a lot of measuring to find one that was the exact size you needed. That's why I think a standard shim set would be the ticket. (Though, admittedly, I have no idea how much they cost.)With mikes design shims can be as simple as washers with a 4-40 hole in them (however washers will add instability and perpendiculariosity (leaning tower of pisa) issues.
Well, I wouldn't be too worried about the 405 nm wavelength, but the 10% loss per mirror is a good point that I had forgotten about. That would be an issue for most builders, I think.Mirrors- I have found that most folks dont like aluminum coated mirrors (the ones I sell) (true they roll off quickly at 405 and are only around 90 something R at other wavelengths).
Still, if someone was willing to purchase, oh, say, a 1 ft square sheet of high-reflectivity mirror and have you cut it up into ~ 1/2 inch squares, surely there would be a way for you to make a profit on the cutting while still keeping the overall cost of the mirrors affordable, yes? Might have to resort to some sort of group-buy on the project, but I think it's doable. (Of course, all of this is predicated upon a completed design...)
I think the range of height adjustment can be defined rather easily. Assume that the maximum number of diodes anyone will want to stack in the vertical direction is 4. That would yield a theoretical maximum of a 4x4 array, which is 16 beams, which when doubled through a PBS would be 32 beams, and that is 33% more than the largest home-built red (Phritzler's 24-diode monster) we've seen to date. Now assume that the worst beam diameter you'd ever get from a single diode is ~ 3 mm. So your maximum height adjustment would be 3 mm times 4 beams, or 12 mm. Or about a half inch, give or take. That will get you close enough for 99% of the projects people have in mind... (As you said, in the absence of an industry-standard specification, make up your own spec!)When discussing height translation, one must first determine "range of height" adjustment necessary. It is a very broad discussion with many variables.
Ahhhh... That makes a lot more sense now that you explain it that way. I never even considered looking at it that way. If you did mount the diodes like that, you're right - you'd have a lot of "dead space" between the beams...I actually was not thinking of a bunch of diodes being combined with a bunch of adjustable mounts, I was actually envisioning a "disc" with diodes pressed in diode to diode (very much like a multi LED flashlight) which is why i asked if those were the beams or the diodes or the lenses
This is going to be complicated, without a doubt. I expect it will look a lot like Phritzler's rig, just with fewer diodes. Also, the final output beam height is probably going to end up being some non-standard value, but for gobs of red, I think people can live with that.would like to see what mike envisions as the mechanical setup not just what he would like the "spots" to look like on the wall.
I've sketched a few simple layouts on paper, but never anything with as many diodes as Mike is contemplating. Still, once you have the basic layout, it will scale more or less evenly up to more diodes, so long as you remember that the height stacking needs to be done from low to high as you move further away from the cube...
Adam
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i look forward to the real deal!
