Simple and cheap portable bluetooth speaker!
I used a SANWU CSR8635 audio board powerew by a 18650 battery. The charger board is a TP4056. I had the battery, the charger and two 34x34mm miniature speakers. I only bought an inexpensive audio board with all the functions integrated.
To assembly i used small 3mm screws and hot glue. For the front grille you can use what you want, i already have the grille you can see in the picture and i just cutted and glued. For another project i used the jack daniels metal box you can find in any shop with the bottle :-)
P.S. I also drill a hole for the led, but it is not necessary if you print the buttons with a clear filament.