Pretty simple speaker, very good battery life, build in bluetooth.
It's assembled with
- laser cut 4mm plywood (31cm x 8cm x 8cm)
- 4x 2" drivers from small notebook speakers (EARISE AL-101, they are surprisingly good)
- 2x 18650 3000mah
- TP4056 charger with cell protection
- bluetooth module
- 3.5mm female jack
- basic on/off switch
- 2x 3W*2 class D amplifier (pam8403)
- optional: 2x step-up(boost) voltage converter
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Step 1: Box
The plywood was cut with "tooth" shapes so it's easier to glue. Heat from the laser bend it a litte.
Apply glue to every panel except top or back and put it together
Step 2: Back Panel..
I forgot about holes on back panel and had to improvise a little. Drill and wood file ftw.
Step 3: Back Panel
Hot glued switch, jack, TP4056 charger (I added a heatsink), pay attention to that little hole next to it and hot glue on charger LEDs, it will lead light to this hole and indicate if battery is charged or not :).
Hole one the left is on/off switch of BT module covered with wood.
Step 4: Wiring
I used a cheap bluetooth module with on/off button and jack output, so you can use it as bluetooth speaker or just as aux speaker when BT is off.
If you want a better module i recommend CSR6035/CSR6045 module (~7$ on aliexpress) but you have to figure the wiring on your own ;). http://www.aliexpress.com/item/Bluetooth-4-0-Stere...
The PAM8403 amplifier is small, powerful,power efficent... and costs nothing
Charger - it's important to use TP4056 WITH cell protection, so they are safe from over discharge
Capacitors that I used may be too big/useless but it's good to have one than not having it at all :D.
optional: to achieve better sound quality on higher volumes put an voltage converter (from 3.0-4.2 to. 5.0v-5.5v) before amplifier (one converter for one amp), most of the bluetooth modules uses 3-4.2v so leave it straight to battery. And you should use batteries with bigger capacity/more of batteries connected in-parallel.
(this one is nice, with 2A current) http://www.aliexpress.com/item/2pc-DC-Boost-conver...
Step 5: Soundproof the Box
Last thing, fill box with wadding or something similar. In my case it's organic cotton (don't use viscose).
Step 6: Batterylife
Cells are from disassembled 6000mah powerbank (kinda doubt they're 3000mah each).
On max volume with aux (BT off) it was playing music for over 8 hours and probably could make another 5 hours if not more.
You can finish the look with lacquer, veneer or leave as it is, looks quite nice ;).
Step 7: CAD Project
Here's my CAD project for 4mm plywood