Boombox v3

thingiverse

This DIY boombox features an affordable design with a 3D printed casing. Part list: * MP3 module with Bluetooth: [click here](http://s.click.aliexpress.com/e/cT4xT2PQ) * Speakers (10 W, 4 Ohm, 52 mm): [click here](http://s.click.aliexpress.com/e/Y3a4ohS) * PAM8610 amplifier: [click here](http://s.click.aliexpress.com/e/byJvI6K8) * BMS plate (2S): [click here](http://s.click.aliexpress.com/e/bdziggha) * Batteries (4x18650): [click here](http://s.click.aliexpress.com/e/yvw8MfA) * Battery holders (2x18650): [click here](http://s.click.aliexpress.com/e/b3hGueoC) * Passive speakers (62 mm): [click here](http://s.click.aliexpress.com/e/b0OctTgy) Audio level and battery indicators can be created from scratch, but you can also use cheap modules like these: * 2S Battery indicator: [click here](http://s.click.aliexpress.com/e/cGaZhsXe) * Audio level module: [click here](http://s.click.aliexpress.com/e/bKTmWeTQ) Passive speakers work best when used in a leakproof body. To prevent leakage, glue the speakers and all halls in the acoustic volumes with silicone mastic or resin glue. The 18650 batteries are connected together in a 2S2P configuration and powered by a BMS protection board that controls high and low charge levels and provides short current protection. You can use special charging boards for 2S batteries, or connect the battery (with BMS) to a serial ballast resistor (5 W ~5 Ohm) directly to 12 V, or through a Step UP voltage regulator (USB 5V to 12V). I use this method and it works fine but produces a lot of heat.