You could easily use something like this: https://www.adafruit.com/products/2465
The only problem with that is you don't get the USB data connection while the device is charging.
@Gordon started
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
You could easily use something like this: https://www.adafruit.com/products/2465
The only problem with that is you don't get the USB data connection while the device is charging.