Little DIY, LED voltage monitor. This is basically nothing new, there are similar products on the market. But since a UK manufacturer couldn’t ship one to Finland, I decided to build it myself. In the attached picture you’ll see all the components I used and how they are joint together. ATtiny85 microcontroller is programmed with ARDUINO_IDE software and a suitable USB programmer. The program code (C++) that controls the LED light is over 100 lines long, so it contains quite a lot of commands, which are then burned into the flash memory of the ATtiny85 chip as binary code. The soldered components take up a bit more space than commercial counterparts, but I'm happy with the result, and it works as it should. Time will tell if it will also last. There are probably smaller components that could be used. Anyway, fun little project and I learned something new.