There’s a good chance that if you build something which includes the ability to top up a lithium-ion battery, it’s going to involve the incredibly common TP4056 charger IC. Now, there’s ...

You have an ESP8266 board like the Wemos D1, a Li-Ion battery, you want to build a small battery-powered sensor that wakes ... You’ll need a TP4056 board, providing charging and battery ...