Portable Multimedia Speakers V2

Hi All,

2 Months back I had custom built a portable multimedia speaker for my friend. It had everything that he needed, MP3/ FM / USB/ SD card/ Aux in / IR remote and external bluetooth

It had few issues

• AC powers connection,not 100% portable
• External Bluetooth needed power source
• Lithium Ion batteries are expensive

In this instructable, I will share how I fixed these problems

Features of the final built

• True Portable
• Lightweight
• 6W / 80DB output
• Mp3/FM/USB/SD/ Aux
• IR Remote
• External Bluetooth
• 6000 mAH battery / 6 to 7 hrs of life with bluetooth
• Battery charging LED indicator
• 5V USB output, can be used for mobile charging too

Material

• Portable Multimedia speakers
• Ols laptop battery
• TP4056 with battery protection
• 3.7 to 5 V DC Step up convertor with USB
• Switch

Tools

• Dremel
• Wood Saw
• Wires
• Soldering iron
• Hot glue gun
• Black OIl paint and brush

We all have at least a laptop at home for years and know that the laptop batteries do not last over 2 to 3 years. I had a bad laptop battery, which I have used for the build

• Using Screwdrivers, break open the outer case
• Extract batteries and separate them from any connections or circuit
• Test individually for voltages ( between 2.5 to 3.7V can be reused)

Put these batteries for charging using TP4056 and measure voltage (open circuit ) should be around 4.2 V.

Few batteries will not detect or charge, You should discard the faulty ones with proper care and as per guidance / regulation followed in your country

Warning: Always use TP4056 or good charger because cheap chargers may over charge your batteries, which could lead to battery explosion

The Batteries I extracted were of LG 3000mAH. I connected two of these in parallel and left it for 4 to 5 hours

Even though the batteries were fully charged, they can carry slide variations in voltage. Leaving them connected for few hours balances them.

Donot not overheat the batteries while charging.....

I am using Electrical tape to hold them together and for covering metal connectors

Since my speakers ran on AC power, it had holes supporting the cables etc. I needed to replace it with a new panel, with holes for

• Bass tube
• A switch
• USB out
• Micro USB charge
• LED Indicator

LED Indicator : I used a transparent PVC / plastic stirrer, which my son likes to collect. I fixed a about 1 inch piece over TP4056 so that it can refract light from LEDs on TP4056

• Batteries are connected to TP4056 at the B+ and B-
• Out+ and Out- of TP4056 via switch connected to step up convertor
• Output of step up converter to MP3 Module and PAM8403 Amp
• Output of PAM8403 to speakers

Test the circuit at each connection. make sure the polarities are correct and not short circuits due to soldering or overheating

Fix the USB output and micro USB in as shown. close the back panel. Test all features works

Leave batteries to recharge.

Features of the final built

• True Portable,
• Lightweight
• 6W / 80DB output
• Mp3/FM/USB/SD/ Aux in
• IR Remote
• External Bluetooth
• 6000 mAH battery / 6 to 7 hrs of life with bluetooth
• Battery charging LED indicator
• 5V USB output, can be used for mobile charging too

Once done enjoy the portable and loud music

Please share your comments and suggestion