First thing I'm going to 3D print is the light box enclosure for the LED array. Inside the box I plan to put mirrors so that there will be more light escaping through the front. Also, I think it should be fairly straightforward to design the out "window" for the light to be the EXACT size of the frame (that is, input the hole diameter, first hole radius, last hole radius, number of scanlines, then it should build a box exactly right. So, this is where I'll do that. We'll be using OpenSCAD as our "programming language" to create STL files (which are suitable as pre-processing files for printing on a number of printers). Also, I plan to put a few "shelves" inside the box to allow various diffusing layers to be placed inside. Should be a bit of fun and a good primer to using OpenSCAD and 3D printing. I'll put the item up on
Thingiverse but should also be available in this thread too. I'll include "NBTV" in the names of any printable items I put on Thingiverse so they're easy to find.
Right, there are a number of measurements that are going to drive the design of the "box" - and these are "parameters" for the OpenSCAD "program" I'll be writing. Let's list those.
1) radius of scanline hole
2) radial distance from disk center to first (inner) scanline hole
3) radial distance from disk center to last (outer) scanline hole
4) thickness of box wall
5) "shelf" positions (there may be more than one)
The current thinking is that the mirror bits are optional and glued in around the shelves
We'll assume that the inside-back does not need a mirror, so the wires can enter anywhere. The circuit board will mask most light going backwards anyway.
Those above parameters will give us the window size, but we need these things too...
6) LED circuit board dimensions (x,y,z)
7) LED circuit board thickness (so we can make a slot for it to slide or clip into)
7) distance of top edge of circuit board from exit window
diameter of the power wires, so we can build a nice exit for them from the box.
9) location of the wire exit points.
I think making the light box the minimal dimension possible, encapsulating the contents, makes sense, so the X/Y/Z of the box will be derived from the other parameters.
It makes the assembly assumptions easier (that is, that no mirror on the back inside is required).
Finally, I think a screw-in backplate makes sense because that gives easy and sturdy access.
I think I've got all that I need, so I'll start making some measurements using my existing LED array. Let me get a picture...
OK, that was interesting. This was actually pretty well constructed. 40 LEDs - no wonder it's so bright. According to their 55000 mcd spec (Yep I know fairly meaningless) but anyway, just saying... that would be 2200000 mcd. Ha! Basically it's a standard "experimental prototype board" with holes, mounted with a closely spaced array of very bright LEDs in a staggered array of 8 strings of 5 LEDs on a board dimensions 70 mm x 40 mm give or take in a box 80 mm x 55 mm x 30 mm and held together with electrician tape. For a diffuser I used some dog-food-can plastic lids and some greaseproof paper. I also have silvered card in there, acting as a mirror on the sides. Interesting. It was a pretty good display (incredibly bright, even in bright sun) so I'll be duplicating that I think.
By the way, ALL units will be metric as far as possible.
So, thinking about the curved auto-calculated framing window - perhaps that's a bad idea
-- it would require the angle of the light box to be set to the tangent of the midpoint of its position, and we don't want that, really. Unless we design things so that's actually what we DO want. Mhhm. That would be the requirement that the center point of the curved lightbox window was horizontally coincident with the center of the disk, or vertically coincident. That's not really that hard to arrange, I suppose. One could always put in an option for a custom size window with no curvature, so let's go with the speccy one for now.
One thing I considered doing is having a moveable light box mount so that you could swing from horizontal position at the side of the disk to vertical position at the top of the disk, so you could watch stuff in either aspect. Will keep that in mind
Right, well that's enough to make a start. I'll head off and do a bit of OpenSCAD programming, put that up on Thingiverse, and post a link. From then on, the up-to-date version will be posted there and well, everyone can print their own
Actually, Thingiverse now lets you order prints of the stuff on their site, so if you don't have/want a 3D printer, you can hopefully get this printed without too much trouble. Of course I have to design something first.
So, be back soon!