Recycled Portable Bluetooth Speakers

Hi All,

I feel good about recycling and in this project, I recycled 3 items

• Speakers : extracted from old desktop speaker
• Lithium ion battery from old laptop
• Wood from left over / discarded stack

Features

• Bluetooth / AUX in/ FM/ TF card
• Ultra thin ( just 50mm)
• Volume control
• Remote control
• 6 to 9 hr battery backup
• Weight Less than 500 gms
• Recycles speakers total output : 6 W

Material

• 2 Speakers ( 3 W each)
• PAM8403 Amplifier with volume control ( 3w+3W)
• MP3 / Bluetooth kit
• 2 Li Ion Battery (18650)
• TP4056 with Battery protection
• 2 DC step up boost - MT3608
• Wires
• PlyWood
• Switch - push button
• Screws ( I extracted these from the original speakers
  • 8 screws to hold speakers
  • 8 screws to hold the back plate

Tools

• Hammer
• Fevicol / PVA glue
• Black Spray paint
• Soldering iron / wire
• Hot gluegun
• JigSaw with wood blade
• Paper tape
• Sand Paper ( 80, 150 and 220 Grit )

To hold all the assembly, we will use 10mm plywood.

• Cut a 2 pieces each of
  • 45mm X 180mm
  • 45mm X 100mm
• Fix them at the edges at 90° as shown
• Use fevicol or PVA glue
• Use paper tape to hold all pieces in place
• Let it dry for 4 hours
• Using 80 grit sandpaper, make the edges smooth and straight

• Cut a 180mm x 110mm plywood or MDF ( 4 mm thickness)
• Make 45mm diameter holes for speakers, Note that my speakers were 50mm diameter
• Cut appropriate holes for
  • Bluetooth / MP3 plate
  • Volume control ( PAM 8403)
  • Switch ( Not show in images, as I forgot and I added it while working on the electronic stuff )
• Spray paint black ( glossy) as shown

• Cut a 180mm x 110mm plywood or MDF ( 4 mm thickness)
• Drill two hole for 16mm dia meter tube for bass as shown
• Add required holes for TP4056 ( micro usb in)
• and LED indicator ( I use a piece of stirrer for led indicator)

• Now to fix the speakers, we need to cut a mdf sheet (4mm thick) as shown
• For battery fix two holder as show, we will hot glue battery on these, later
• Let it fry for 4 hours

• Follow the logical circuit diagram ( each single line represents both positive and negative wires)
• TP4056 is connected to battery and two MT 3608
• MT3608 is set at 5 V for PAM8403 and 9 V for Bluetooth Kit
• Output from Bluetooth kit is connected to input of PAM8403
• Two speakers are connected to PAM8403
• Test the circuit before Assembly

Putting all together is difficult and take time, I fixed thing in following order

• Power switch
• PAM8403
• Speakers
• TP4056 and MT3608
• Battery
• Bluetooth kit

Pre-solder long wires to PAM8403, bluetooth kit and TP4056

Hot glue things in place

After all the wiring is done, close the back panel. I used 8 screws to ensure no sound leakage.

Test it using different inputs like FM, USB etc

Improvement for furture

• My speakers were 2w and output 3w, so disturbance at high volume
• Current limited by TP4056 at high volumes, due to high current pulled by amplifier

Please share your comments, if you liked it