I was thinking on the lines of logic gates, flip flops working with ICs like the 555 timer chip, and so on.
Logic gates are not really difficult to understand, but I do like the idea of learning and creating digital logic circuits. A nice example project could be to build ones own stepper driver, using the 555 timer in combination with shcmitt trigger and darlinton pair IC's, Mosfets, etc...
I agree with @frogandtoad, logic gates are not difficult to understand, and if you get the 555 timer to give you a 50% square wave at a chosen frequency it should not be too difficult get any required digital level output signal.
If you put the following search term into eBay, Amazon etc.
4000 Series CMOS Logic ICs Assortment
You get 30 different ICs for about 30 dollars.
Includes multichannel And Nand Or Xor chips.
SteveC - Topple Rudd Poltman
If anyone has a good source for learning, it would be a big help.
This is a detailed introduction, and quite good:
There are many many good tutorials on this topic, but this one is quite comprehensive, so I thought it was a pretty good choice 🙂
I remember the first time in my computer architecture studies when I came across Boolean algebra?
I was like WTH... I don't even understand normal algebra!... Who is this George guy? LOL
Logic gates were one of the first things I studied, even before electronics. I remember having a very large manual from Fairchild Semiconductor. It contained a detailed description of all their logic chips. Pinouts, block diagrams, schematics of the internal transistor circuits, as well as truth tables, and even some applications circuits. I was fascinated by the logic circuits. I guess it never got old as I still find them quite interesting even today. But now I use FPGA and CPDL instead of individual chips.