We see more and more projects that use custom molds and casting materials. The latest is this custom seven segment display which [Ray74] put together. The idea of making your own LED displays couldn’t be much easier than this — everything but the LEDs and wire is available at the craft store.
He started by making models of each segment out of pink erasers. The lower left image of the vignette above shows the eraser segments super glued to some poster board. The decimal is a pencil eraser, with a fence of wood to contain the molding material. Amazing Mold Putty was mixed and pressed into place resulting in the mold shown in the upper right.
From there, [Ray] cast the clear epoxy three times. Once dried the clear pieces were sanded, which will shape them up physically but also serves to diffuse the light. They were then placed inside of another mold form and an epoxy pour — this time doped with black enamel paint — finishes the 7-segment module. The final step is to glue the LEDs on the back side and wire them up.
This definitely trumps the build which Hackaday Alum [Kevin Dady] pulled off using hot glue sticks as light pipes.
Nice work.
As an alternative, I’ve made custom 7-segment displays using two stacked 3/16″ laser-cut acrylic sheets, with white copy paper as the diffuser, and SMD LEDs. I tried both white and clear silicone bathtub sealant as diffusing material, but found that a sheet of copy paper sandwiched between the top layer of acrylic and a smoked translucent acrylic sheet works better. My digits were much smaller (about 1″x1″)…but the approach allowed me to create a complete 4-digit LED clock with all supporting circuitry in about a 1/2″ thick package – Smoked Acrylic – Office Paper – 2x Black Acrylic sheets – PCB.
pics, or it didn’t happen ;D
http://bitpuppy.com/dawnclock/
(yes, it’s a clock for my 4-year-old daughter to let her know when it’s OK to leave her room in the morning, since she’s such an early riser…even plays “doe a deer” and “my little pony” theme song)
That’s fantastic. Thanks for sharing.
Very cool. Nice build for a useful thing.
I made something for the same purpose but much simpler for my sister’s son: a javascript HTML page in an old PocketPC to show just a sun or the moon depending on the time.
That is excellent – I hadn’t thought of paper yet, nice trick. I was thinking of trying edge lit acrylic blocks that have been smoked/brushed for diffusion on the front – seems like someone, somewhere, would have tried that already…
this is so cool. and there’s nothing to stop you from making 9-, 10-, 16-, 17- whatever-segment specialty displays. maybe even cursive
That is very cool Ray, and more work than I would do. I happen to work with Ray, he is an expert alarm technician, he also has made a home weather station that can text him.
Pour the first 1/2 of the led segments with a more opaque resin. even just a thin 1/8th inch of white or mixing white and clear together will make a huge difference in the even spread of the light. also when making huge ones, more led’s are better than brighter led’s again even light spread.
Never made 7 segment displays, but I have cast resin displays before for automotive accent lighting and getting some of the white resin solved all my diffusion problems.
Fantastic work, and also to dizot.
I know this isn’t quite in the spirit of hacakday, but I’d like to get some LED displays custom made to my design, professionally – ie fully epoxy encapsulated etc.
Does anyone know anything about how I would go about doing that, what minimum order sizes are likely to be, setup costs, etc, and do I just pick a factory randomly from alibaba?
Another good tutorial to making seven segment display
https://magicoflogiccp.blogspot.com/2018/03/cse260-project-making-my-own-7-segment.html