By the way, if you speak Estonian, I have different and more content in that part of the website.
Realization of Kadi Pajupuu's idea. Three dimensional textile printing.
If 12V drill batteries die and you are lucky to have a spare old car battery ...
Need more buttons on Arduino / ATtiny than there are pins left? If you have an extra analog input, you can attach more than one button to that with voltage divider setup. This tiny library helps to read that kind of input.
Tiny simple library that reads button inputs in a debounced way (eliminates noise and unsure states). Adding lots of buttons is effortless.
Code and schematics for a basic LED clock that shows hours, minutes and seconds in binary-coded-decimal.