A project log for RPN Nixie Calculator

A programmable RPN calculator using way too many Nixie tubes

robert.c.baruchrobert.c.baruch 06/02/2016 at 02:342 Comments

I found a cheap USB keyboard controller chip! It is the Holtek HT82K629A. It requires a minimum of passives, plus a 6MHz crystal, and you're done -- just hook it up to USB and it looks like a standard keyboard.

You don't get to say which key is which: a given intersection of row and column is hardwired to be a given key. I've hooked up the "1" key. When I plug it in to my computer, it works great. I can type 1's all day. So now I don't need an FRDM board to run the keyboard.


Sondre wrote 12/23/2018 at 13:46 point

Hello, how did you do it with drivers? Ive tryed to set up the same as you, but my computer does not seem to recognize the device, do you have any tips?

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Samu Kiiski wrote 07/11/2017 at 19:27 point

I ordered one. I also ordered some tactile buttons. I'll find out how small qwerty-keyboard I could make out of these.

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