How do you prototype your circuit designs?

[mojibber]

I've been working on a couple new designs recently to enable more keys for a given number of microcontroller pins. I've tried using the Japanese Duplex Matrix (talked about on https://kbd.news/The-Japanese-duplex-matrix-1391.html) as well as a design using a demultiplexer for the columns. I've been breadboarding these versions to test them out, where I write and flash firmware onto a pro micro and build a smaller version of the matrix on a board and then validate that everything is working as expected (it's not always )

This is time consuming but mostly an accurate way of doing this, but I wonder if there are better ways? Does anyone do this fully in software through simulating the circuit and also the controller to see what works and identify issues? Would be great to understand other workflows in the hope of improving my own!

[vvp]

http://www.openmusiclabs.com/learning/digital/input-matrix-scanning/
E.g. I used shift registers in K84CS.

[mojibber]

Nice resource! But I was wondering more how you test and prototype the designs.

[vvp]

I did not do breadboards nor software simulations in the case of K80CS and K84CS. I went directly to the "final" version of all electronics and software. My "final" versions turned out to work well. Notice that is for electronics and software. Both electronics and software is rather easy for such a simple device as a keyboard (simple digital logic at low frequency and low power). I had 7 prototypes before the final version of the case shape though.

I did not do breadboards for K80CS/K84CS. But I did some very limited breadboards for a more complicated project (30 kW electronic speed controller for a 3-phase electric motor). I did simulations for it as well.

[dm]

Have you tried LTSpice? I believe it is the industry standard for circuit simulation.