There's also the Gigatron. I seem to recall that there was some interesting work done getting it to run 6502 code.

https://gigatron.io

Jeffs unite!

One possible low-cost solution, if I may? I've used some 24-key and 44-key IR Remotes in PIC projects in the past. The IR Receiver IC comes with the keypad and only needs a single pin and pull-up on the host. The NEC IR protocol is relatively easy to decode and you can print custom keypad overlays ...

(It's a pity that 5x4 keypads aren't quite as cheaply available: it's a natural size for hex+functions, or for a calculator. 16 keys isn't quite enough, and 32 is a lot.)

If you'll indulge me in a bit of rambling about this project... :D

That was precisely the problem I had for the longest time ...

Thanks, all, for the advice and tips! I appreciate your helping a newb like me.

I might try giving the "pull up" design a shot. I'm thinking the required changes to the scanning logic should be pretty straightforward, but we shall see.

On the one hand, I hate to change a working design. On the ...

Hi all! First post here.

I'm working on adding one of those ubiquitous, cheap, 4x4 matrix keypads to my Ben Eater build.

The good news is, it works . (So far at least!) But maybe that's just due to dumb luck? I'm still very much a learner when it comes to hardware, so I'm not sure I'm using the ...