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A comment on Ultrathin business card runs a fluid simulation. Parent comment

Re:Ultrathin business card runs a fluid simulation by 4gotunameagain on Friday August 08, 2025 @08:12AM (#44836094)
There's a BOM, you can find out. Plus some peanuts for the PCB :)

Now whether you get it populated or not..

https://github.com/Nicholas-L-Johnson/flip-card/blob/main/ki...

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Re:Ultrathin business card runs a fluid simulation by unwind on Friday August 08, 2025 @08:33AM (#44836259)
Just as a point of interest perhaps for folks who are not familiar with PCB design and modern electronics: the "huge" matrix of 21x21=441 LEDs would, with the specified LED from the bill of materials (BOM) cost all of $6.

That is based on the price for low quantity (1-500 pieces) though; if you were to build more than one board you would buy more LEDs, pushing the per-LED price (way) down. You can get 4,000 LEDs for $30.'

Edit: here is the LED in question, from the BOM [1].

[1]: https://jlcpcb.com/partdetail/C497920

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