Way back..no, waaay back, I learned assembly language on a TRS-80. The TRS-80 had a Z80 processor, which is an 8-bit workhorse CPU that was used in a lot of different pcs (Z80 clones were even used in Soviet computers). I spent a lot of time poring over Rodney Zak's "Programming the Z80" and even managed to create a couple of very simple assembly language games, including a version of breakout and a version of snake.
Much, much later I had the opportunity to work on some software used to control a hardware testing harness used for testing power amplifier microchips. The testing harness had a lot of settings and they were all controlled at a bit level. Users would configure their testing scenario in a UI using check boxes and radio buttons and drop-down combo boxes, and the software would translate that scenario into a couple of 8-bit numbers that would be sent in serial to the testing harness.
It was a fun project that involved a lot of learning and required me to dust off my binary math skills. To assist me in that project, I created this binary calculator/conversion utility. It's come in handy a few times since. For example, when trying to do HSB (hue saturation brightness) to RGB (red green blue) conversion when working on an LED light strip / arduino project. Hopefully you'll find it useful too!