A portable bluetooth speaker that functions as a power bank.
Powered by conventional rechargeable AA-cells (in 4S2P) that can be charged via the USB-C port or by soldering solar cells to the on-board headers.
The power bank outputs include dual USB-A ports and a Qi wireless charger that features overheating protection and foreign object detection.
The bluetooth speaker features volume, power and track control buttons, a TI amplifier and mono-speaker. Functionality can be expanded to support stereo but costs are kept down by using 1 amp/speaker. Included are all design files in Altium and EasyEDA formats, as well as Gerber and Pick-and-Place files- plus some nice images too.