Last year I saw a friend of mine, Kenneth at thelifeofkenneth.com, had a clever idea where he made a little blinking indicator with a 555 timer and a float switch to let you know when you needed to add water to your christmas tree stand. I had ordered some float switches at the time, and they’ve sat around on my bench since then. August seems like the appropriate time to be making Christmas associated projects, so I’m going to shamelessly rip off his idea.
As you can imagine, the schematic is very simple. A USB port for power, a 555 timer, a couple LEDs and passives, and the screw terminal for the float switch.
