After making the single pane night light Lithophane holder, I decided to try something that would hold more images.  I first had to find a light source, and thanks to folks at Reddit for the inspiration, I found one that I think may work.  It's on order but I have already roughed out a design to hold the light source inside a holder that is going to rotate.  The bearing is not the right type (its a slew bearing and not a thrust bearing), roughly based on this thing.  I could have used a thrust bearing but I couldn't wrap my head around how to retain the bb's that will be used with it, and I did not want the whole thing to fall apart. There is not much weight however and lots of bearing surface, so I'm hopeful the poor choice of bearing will work out in the end.  If not I will have to figure something else out.  

Unless the stars really align for this one, it will be a while before I can post it up though.  I get the feeling it will take a few test prints to get everything right.  I'm planning to print this using Hatchbox Wood PLA, which I have had good luck with in the past.

I still need to re-test the single lithophane night light, hopefully I can get that one posted well before Christmas.

Update 12-11-2021: Just a couple of parts from this.  Having it on the printer really made me realize how large this will end up, but I think it will be OK.  I can always scale it down if I have to.  It should still fit on an Ender3.   The cone thing is not some crazy colander, it's a diffuser with holes to allow heat to escape from the LEDs (the top also has holes).  The base will have some holes to also allow an updraft around the LED holder.  I also found another possible light source for a lithopane - its an Ikea HALVKLART, which appears to be a USB puck light.  It would probably even work with this design since I have designed it to hold a 100mm diameter light source.  I'm gonna stick with what I have though, for now at least.  If it turns out that it's just too large I may try something else.

Update 12/18/2021 - I'm almost done printing this, but I still have the base to do, and I may run out of the wonderful Hatchbox Wood PLA (which is sold out on Amazon unfortunately).  I may need to make the base in another color but I will attempt it with what I have left.  I decided to go with the Ikea HALVKLART as the light source, since it is very bright and already has a nice diffuser.  It pulls about (edit) 170mA at 5V and it's a decently bright light.  I designed a very simple way to turn the light on and off with a tap of the knob, which is yet to be tested.  I'm hoping to get this done this week so I can send it off, though it will arrive too late for Christmas I'm sure.  I will try and get this posted as soon as I can verify it works.

Update 12/20/2021 - Getting very close now, I'm printing the last part before I can partly assemble it and confirm the fit on the slew bearing using some 6mm airsoft BB's as bearings.  I decided to do a filament swap on the base to both conserve PLA and maybe make a smoother surface for the BB's to roll on.  I also did a quick test of the Ikea LED and it works really well, even with the lights on.  There is a cool pattern that the top throws to the ceiling as well, it's not quite like random stars but I like it.  The light "switch" which is really just a push rod, also works.

Update 12/21/2021 - I put this together and found that the mechanism for pressing the top of the LED to turn it off and on was not working well, so I re-designed it and hopefully it will work this time.  It is really just a pushrod, but it has to allow the top to turn while the base of the rod does not wobble off the LED.  As usual I think I over-complicated this but if the stupid complex version doesn't work I will revert to something simpler.

Update 12/24/2021 - This was completed and works great (also looks pretty good too).  I posted this in another blog entry above, but thought I should post here also - the final design is now posted at Instructables (where it got featured in "Workshop" and is entered in their "Anything Goes" contest).  It is also uploaded to thingiverse:

www.instructables.com/Triple-Pane-Lithophane-Lamp/
www.thingiverse.com/thing:5172186

I printed the Star Wars inspired Lithophane holder, and although it required some sanding to get the lithophane to fit, and it was still tight, it looks great.  I used Polymaker Galaxy Blue PLA which has glitter incorporated (see pic at left), and it prints great (no clogs on the 0.4mm nozzle).  Since printing it, I made some tweaks to the design and will need to make another print of the re-scaled holder to test before I can post it (made it a bit larger in the x and y to hopefully help the fit).  I'm planning to post a version with a solid side and possibly one with a different side light design, along with instructions and a blank image file template which will be the exact size of the image I used to create the lithophane on 3dp.rocks/lithophane/.

The design also changed a bit since the last post, since I found that the GE Coverlite LED's project up a but, so I had to make the holder taller, with a bit of space in the base for the LED projection to develop and cover the whole lithophane (otherwise it would be dark in the bottom corners).  Overall I like it though, and I think it will be a great gift.  Note that the pic is intentionally blurred out, but the lithophane is pretty sharply defined (was printed at 0.1mm layer height with a 0.4mm nozzle).

I'm also thinking about another lithophane desk lamp, but I'm still looking for a good (plug in) LED light source to use with it.

Update 12/20/2021 - Things have been really busy with the other projects and work, so I have not yet posted this.  But I have a couple of other design ideas that I have been working on here and there, so there will be at least one, maybe two different designs when it is uploaded.

Update 12/24/2021 - I was able to test three designs for the side panels and they all work, though the snowflake pattern is a big pain to remove supports from.  However I had to redesign the base since it was never fitting quite right.  I plan to print it today and hopefully get the modifications tested. 

RJSampio @ Thinigverse printed the VOM case for the MakerHawk USB multimeter, and it looks great printed that way. Theirs' is the Bluetooth version however, and so asked if I would add a hole for the Bluetooth LEDs, and make the case thinner due to some interference they had with USB cables.  I so far have not had problems with interference with USB cables on the original design, but it was pretty simple to modify the design, and I think it would also work with FDM or Resin, since the walls are still thick enough. 

There will be 2 versions of the thinner case, one will be for the not BT version and the other will have a hole for the Bluetooth status LED's to show through.  But since I don't have the BT version, it will be a WIP until tested.  Both versions are not yet posted, but hopefully will be soon.

UPDATE 12/9/2021: The slimmer version with a top for both the BT and non-BT versions is posted to Thingiverse here:
www.thingiverse.com/thing:5160155

Lithophanes (or "Lithopanes" as I have been known to incorrectly call them :-) are super easy to make, thanks to some cool web based tools which allow uploading an image, setting some parameters and they spit out a STL ready to slice.  I have never gotten into printing lithophanes until recently, since I thought they wouldn't look good, however, seeing some of the really good ones that are occasionally posted to reddit or thingiverse changed my mind on that.  People are getting amazing results with 0.1mm resolution prints.  There are many cool designs for illuminating lithophanes, but I could not find what I was looking for.

Recently I saw some GE LED "CoverLite" night lights, and thought they may be ideal as a lithophane light source.  I ordered some to test, and after removing the cover from the LED, I'm sure they will work now.  I'm working on a Star Wars themed lithophane to help celebrate a close relative's new baby, and it will be based off a GE CoverLite source. 

I'm printing the lithophane now, using an image that is 1300x864 pixels.  That size is just what I arbitrarily cropped the image to, and then designed the holder around the STL that was created (so if I use this again, I will need to start with the same size image if I want it to fit). 

I used these settings (see pics below) on https://3dp.rocks/lithophane/, and it created a lithophane that is an outward facing arc about 70mm tall and 94mm wide (tip to tip, not along the arc).  The first test lithophane which was generated looked great when I tried printing it, unfortunately I had used a wrong setting, thinking I could make a lithophane with a flat front face, however it would take way too much light for that to work, so I am using the design facing out for my next attempt.  One thing that was suggested in a video (sorry I lost the link otherwise I would credit the person), they said to set the "Image Setting" slider to "Positive Image", otherwise it would look like a negative image when backlit (I believe).    

These 3 images below are from https://3dp.rocks/lithophane/:

I'm still testing these settings however, and I need to print the holder and see if it will work, but I'm hopeful.  If it all works out, I may try a Christmas ornament or maybe a small desk lamp with some other pics of the new baby.  If it works out well enough to give it as a gift, I will post it up to Thingiverse or Prusa Printers with instructions on how to get a compatible lithophane to fit the holder.

I'm using some TacBears white PLA which is almost a milkjug white and I thought pretty much only good for lithophanes.  I would not recommend that filamaent otherwise, but it so far has been OK (I did have one clog on the 2nd test print though).  For the holder, I'm gonna use some Polymaker Glitter (Dark Blue) PLA which I got on a Cyber Monday sale for $23.99.

Update 12/9/2021: The test print is done and looks good, but I made some changes to help with fit, and need to test those changes before I can post it up.  Pics here.