The randomness factor is quite mesmerizing, each flap search ending at a different timing along with the mechanical aspect make this a very fun thing to watch. Old tech was so cool..
Open source “split-flap” mechanical display
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Re: Open source “split-flap” mechanical display
#12Fantastic. Glyphs can be loaded in an arbitrary order. For a given corpus (e.g. city names, American English digraphs) how does glyph order affect the time taken to update the display? Is there an optimal ordering? If your display could accommodate 5% more glyphs, which would you add and why? (With apologies to anyone revising for an exam this summer.)
You can only flip in one direction, so the time taken to update is entirely dependent on the previous state. Worst case you'd need to display the previous character (B -> A for alphabetical order) and would have to flip through the entire alphabet to get to it.
> You can only flip in one direction, so the time taken to update is entirely dependent on the previous state. Worst case you'd need to display the previous character (B -> A for alphabetical order) and would have to flip through the entire alphabet to get to it.
This only applies if you have only one copy of each letter.
You can consider having more copies of frequent letters mixed into the stack, if the stack's thickness allows.
Re: Open source “split-flap” mechanical display
#13Earlier quoted context omitted.
You can only flip in one direction, so the time taken to update is entirely dependent on the previous state. Worst case you'd need to display the previous character (B -> A for alphabetical order) and would have to flip through the entire alphabet to get to it.
> You can only flip in one direction, so the time taken to update is entirely dependent on the previous state. Worst case you'd need to display the previous character (B -> A for alphabetical order) and would have to flip through the entire alphabet to get to it. This only applies if you have only one copy of each letter. You can consider having more copies of frequent letters mixed into the stack, if the stack's thi…
Wouldn't that only help with the average case, not the worst case? Either you have multiple copies of every character (in which case you're still flipping through the same number of characters as the original stack), or some characters don't have duplicates.
Re: Open source “split-flap” mechanical display
#14I've always loved these - this company makes one that looks great, but isn't open source (there is an API that has yet to be released): https://www.vestaboard.com
It's also quite expensive, but has a clever design where the individual split-flap modules can be replaced.
There are also custom ones you can have made (probably even more expensive), but they're mostly targeting enterprise: https://www.oatfoundry.com/split-flap/
It'd be neat to have one you could hook up to some market API to make a little stock ticker.
Very cool to see work an open source design.
Re: Open source “split-flap” mechanical display
#15This is great! Love seeing hardware hacks like this on HN :)
Beyond just being a cool project, the detail in the README on Github is really amazing and I've bookmarked this as a great reference for releasing open-source hardware as a git repository. CAD files, a bill of materials, detailed usage instructions, etc.
Re: Open source “split-flap” mechanical display
#16Airports in the 80s/90s were all about those displays
The sound of Flap flap flap flap flap still in my memory
Re: Open source “split-flap” mechanical display
#17Fantastic. Glyphs can be loaded in an arbitrary order. For a given corpus (e.g. city names, American English digraphs) how does glyph order affect the time taken to update the display? Is there an optimal ordering? If your display could accommodate 5% more glyphs, which would you add and why? (With apologies to anyone revising for an exam this summer.)
We made a small project with all the 6 letter words from the Italian dictionary (as an homage to the inventor and producer of the split flap display: Solari from Udine) ordered in a way to produce “the least effort”.
Re: Open source “split-flap” mechanical display
#18Moving parts made of acrylic, though. Will not wear well. Delrin, maybe? It's now possible to buy commercial split-flap displays from China. $180/char.[1] [1] https://splitflap.en.alibaba.com/
For some applications you wouldn't worry too much.
A score display for a sports team might only do one or two rotations per week.
Of course, for a clock or airport flight display, it'd be a different matter!
Re: Open source “split-flap” mechanical display
#19Scott Bezek has a great video on "How a Split Flap Display Works" [0].
He also sells blank "flaps" on Tindie [1].
The documentation on how to build the Split Flap is also really awesome [2], including how to cut your own flaps [3].
I've been following this project for a while. It's pretty awesome. I estimate about $10 per character (as opposed to the $180/character (!!) another poster mentioned through Alibaba), with a large portion of the cost being the custom cut "flaps" (in small quantities). It seems like the cost could get in the $2-$4 range per character but I couldn't figure out how to do it without a significant amount of labor involved in cutting the flaps.
FYI, there's also a company called Oat Foundry that sells large split-flap displays [4]. I seem to remember the cost being in the $10k+ region but I don't see a price and I could be way off base.
Oh, interesting, I see Vestaboard also has a (smaller) one for around $3k [5].
[0] https://youtu.be/UAQJJAQSg_g
[1] https://www.tindie.com/products/scottbez1/blank-split-flap-d...
[2] https://github.com/scottbez1/splitflap/wiki
[3] https://github.com/scottbez1/splitflap/wiki/Cut-flaps
Re: Open source “split-flap” mechanical display
#20These screens are awesome. I did a design a few years ago, aiming for super low cost and easy build. Made a few units but it needs more refinement: https://splapr.com/