The internet is cluttered with pointless devices, promising convenience but offering little more than outdated software, security vulnerabilities, and subscription services offering an umbilical link to companies that can put up prices when they feel like it or even go bust.

This IoT battery charger by Liz Clarke, Kattni Rembor, and the Ruiz brothers avoids all these pitfalls. For one, it’s built using open-source hardware and software, so should Adafruit vanish tomorrow, it’ll still work. And in contrast to many other IoT devices, it’s actually useful.

This is a pretty simple build, beautifully executed: it’s just an Adafruit ESP32-S2 Reverse TFT Feather (a Feather word with a built-in TFT screen) and a MAX17048 LiPoly battery monitor chip. The chip detects your battery’s charge, and the Feather displays it on screen. So far so good, but the IoT element is where this build shines. Using Adafruit IO, the device can let you know when the battery is charged, via a text message or an email.