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Thread: And before we did lasers...we did Light Boxes...

  1. #21
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    Quote Originally Posted by buffo View Post
    I was considering mounting the strips in some aluminum U-channel, and then attaching the channel to the box... That way when you pulled the lid (or the base) off, you would still have something supporting the strip that was spanning the gap. I figured I could easily add a strip of frosted plastic to the top of the U-channel to help diffuse the light...
    That's not a bad idea, but the U-channel would have to be shallow in order to not cast shadows from it's raised sides, wouldn't it? The waterproof strips (IP 67 rated) provide inherent bridging support plus some diffusing. But my intent is to use the lighter water resistant strips and support each strip at the corners in each baffle just in front of each baffle.

    I've designed several methods of mounting the LED strips including open annular rings, the width of a strip, affixed (bonded) to each baffle, with diameters just beyond the line of sight into the box. But the KISS principle has brought me back to just doing open rectangular mountings, with a gap on one side for the in/out leads. Each successive baffle's rectangular strip size "can" be smaller to conserve strip length per baffle (and maybe the smaller hole baffles can get by with fewer LEDs per strip) but each baffle's strip requires input and output leads pigtails in my design. I'll probably just use plastic 4-40 hex stand-offs to support the top two corners of each strip in a baffle. The bottom two corners don't need anything but gravity (imho). I've not yet decided on using strips with 1.3" LED spacing or .65" spacing.

    I just made multiple side-by-side cuts to get the kerf wide enough to slide the panels in place.
    Been there, done that...and for these dados it was simple with circular table saw blades that had 1/8" kerfs. Now you have to search and search for anything larger than 1/16" kerf blades in the 7-1/4 to 8-1/12" diameter range.

    Huh... I've never even heard of such a thing! Got pics?
    My drill press is tiny (it's a Harbor Freight special), so I don't think I'd have enough clearance from the center of the chuck to the support stand at the rear to be able to cut anything larger than ~ a 4 inch radius. But I might be able to pull it off using a handheld drill... [/QUOTE]

    Here's a radial arm drill (hole cutter) from Rockler but using it with a drill press is an absolute must and should be used to cut the insert hole(s) when they are out of the box. Back in the day, the largest diameter "circular hole cutter" was 2-1/2", primarily used for door latch holes. Now they go up to 5" in diameter but to get anything larger requires the radial arm type...or a CNC machine.

    https://www.rockler.com/mibro-adjust...gaAsVoEALw_wcB
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  2. #22
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    Quote Originally Posted by lasermaster1977 View Post
    That's not a bad idea, but the U-channel would have to be shallow in order to not cast shadows from it's raised sides, wouldn't it? The waterproof strips (IP 67 rated) provide inherent bridging support plus some diffusing. But my intent is to use the lighter water resistant strips and support each strip at the corners in each baffle just in front of each baffle.
    Would this work for your application?
    https://www.superbrightleds.com/more...saAtM3EALw_wcB


    Quote Originally Posted by lasermaster1977 View Post
    @ Adam I have the same hole saw. If you are careful and go slow you can use a battery powered hand drill.

  3. #23
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    Quote Originally Posted by Lazerjock View Post
    Would this work for your application?
    https://www.superbrightleds.com/more...saAtM3EALw_wcB


    @ Adam I have the same hole saw. If you are careful and go slow you can use a battery powered hand drill.
    Laserjock, yeah, those look to be well suited, and there is one that has a curved diffuser that Adam would like. Thanks for the link! Those would be cool for lots of different LED applications.

    Edit: I do believe that in the small light box enclosure, bounce lighting is the key to achieving an even intensity on the viewing area. That is the primary reason for painting the inside of the box and both sides of the partitions flat white.
    Last edited by lasermaster1977; 10-11-2021 at 13:24.
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  4. #24
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    Quote Originally Posted by lasermaster1977 View Post
    snip

    Edit: I do believe that in the small light box enclosure, bounce lighting is the key to achieving an even intensity on the viewing area. That is the primary reason for painting the inside of the box and both sides of the partitions flat white.
    Okay, I've been watching this for a while and, OMG NO, in a brute force "projector" you want small bare filaments - or small emitters working with LEDs. Forget white walls - think mirrors. White walls are diffusers - you don't want a diffused effect - you want as close to point sources as possible to get some resolution to the effect. If you've got a soft white bulb and it looks lousy, and you've got a clear bulb with a small filament or a filament that's aligned so it looks small to your output panel - and it looks awesome - there's a lesson to be learnt...
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  5. #25
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    Quote Originally Posted by laserist View Post
    Okay, I've been watching this for a while and, OMG NO, in a brute force "projector" you want small bare filaments - or small emitters working with LEDs. Forget white walls - think mirrors. White walls are diffusers - you don't want a diffused effect - you want as close to point sources as possible to get some resolution to the effect. If you've got a soft white bulb and it looks lousy, and you've got a clear bulb with a small filament or a filament that's aligned so it looks small to your output panel - and it looks awesome - there's a lesson to be learnt...
    I agree, but please don't take me so literally. The LEDs do mimic the point-source filament.
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  6. #26
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    Thanks for the link to superbrightleds.com, Chris! They have several sizes of aluminum channel (including one with a diffuser) that I think will work really well.

    The reason I'm thinking of using the diffuser is because I'm after a smooth, consistent color intensity across the entire circle. Right now I can see the hot spots formed by the individual LED emitters, and that is not the effect I'm looking for. I suppose if I were using mirrored sheets instead of thin plywood that is painted white, I might see different results, but I'm not ready to try cutting large diameter circles in sheets of mirrored glass...

    Speaking of drilling those large diameter circles, my hole-saw kit has bits that range from 1" to 6" in diameter, which isn't any larger than what you can get with that adjustable radius cutting tool. The hole in the front plate on my design needs to be 8.75 inches in diameter, so it looks like I'll need to do that one with the jigsaw again.

    Although, after a bit more searching, I did find a similar adjustable hole-cutting tool that was designed for sheetrock... It goes all the way up to a 16 inch diameter hole, which is great, but it's completely manual, so that sucks. Still, I could probably use one of these to cut the thin plywood if I worked at it, but it would be slow going.

    Decisions, decisions!

    Adam

  7. #27
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    Quote Originally Posted by buffo View Post
    , but I'm not ready to try cutting large diameter circles in sheets of mirrored glass...

    Adam
    Don't think "mirror" literally, think reflectively, strategically.

    Wow, 8.75" diameter. I love it.
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  8. #28
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    Default Finally did my first mock-up jig for video testing...

    Adam and Steve's comments have really put a fire under my ass to get some practical testing done. My heart felt thanks to you two, and to lazerjock as well whose valuable input and insights got this ball rolling. Edit: Sadly, in the process I burnt out most of a WB2812B 5v strip of 44 RGB LEDs...boo...hiss.

    I am really excited and greatly encouraged by my first results both visually and with digital video recording simply using a cheap controller. The vast possibilities with fairly simple variations on how the LED strip light box components associate with each other blow my mind!

    Once I've done a few more digital video tests of a single partition I post the link to my YouTube channel here.

    (whoooohoo)
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  9. #29
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    Quote Originally Posted by buffo View Post
    Although, after a bit more searching, I did find a similar adjustable hole-cutting tool that was designed for sheetrock... It goes all the way up to a 16 inch diameter hole, which is great, but it's completely manual, so that sucks. Still, I could probably use one of these to cut the thin plywood if I worked at it, but it would be slow going.

    Decisions, decisions!

    Adam

    Adam,
    If you have a router you can make a jig to cut circles easily.

    https://www.thisoldhouse.com/house-o...g-for-a-router

    If you don't have a router. Time to visit Harbor Freight.

    https://www.harborfreight.com/electr...ool-42831.html

  10. #30
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    I have a router, but it's huge. (2.5 HP) I think something like a Roto-Zip would be more appropriate for the jig you linked to. (Remember that the stuff we're cutting is only 1/8 inch thick or less.)

    The Harbor Freight tool is cheap enough that I might just give it a shot though.

    Adam

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