A small USB coin cell charger for 2032 series rechargeable batteries LIR2032 etc. Beware, not all 2032 button cells are rechargeable.
This project uses Lithium Button batteries, please note the warnings here – Do Not short out the batteries, and Do Not swallow them.
WARNING V1 & V2 Battery holder is the wrong way around. This should be sorted in V3
Resistors are R1 – 1K and R2 – 333 Ohms for a charge rate of 35mA (check your battery specs)
IC is LIH7 or LTC4054
USB connector is made from PCB, but unfortunatly OSH park’s PCB’s are just slightly too thin, so a thick piece of card 0.5mm glued to the underside of the PCB takes up the slack in the USB socket.