Lithium-ion batteries are everywhere and they are awesome also for hobbyist projects. I’ve been tempted more than once to use old smartphone batteries in my projects, but recharging them might be a problem.
Well, this time I tried my hand at recharging small coin-cells like the LiR2032. I’ve been looking around for commercial chargers, but they seem to be kind of unpopular. Turns out you can do one yourself with less than 2€.