Adafruit Industries Adafruit Industries LiIon/LiPoly Backpack Add-On for Pro Trinket/ItsyBitsy
If you have an ItsyBitsy or Pro Trinket you probably know it's the perfect little size for a portable project. This LiPoly backpack makes it really easy to do! Instead of wiring 2 or 3 boards together to make a charging system, this little PCB sits on top of the PCB and allows a LiPoly/LiIon battery to plug in. When the Pro Trinket or ItsyBitsy USB port is powered, the battery is recharged automatically. Unplug the USB port and the microcontroller will switch over to the rechargeable battery.
Adafruit Industries LiIon/LiPoly Backpack Add-On for Pro Trinket/ItsyBitsy