I always wanted to make a cheap bluetooth speaker, and now my build is finish.
I wanted it to be cheap, easy to build, powerful and with a good battery life.
Specs of the speaker:
- 2 x 25W amp ( initially 2x 10W )
- 4800Mah 12v battery ( actually, more like ~ 1700mah )
- reused PSP case
- reused sony home cinema speakers ( 2 x 30W 3 ohm )
To simplify the build, i used a prebuild amplifier, 12V universal battery with charger socket integrated and protection board, so no need to solder anything.
The total cost of the amp is about 20€ shipping included.
Step 1: Parts
The parts of the speaker are all aviable on Aliexpress or ebay, they are cheap and easy to find and with free shipping.
I had already a pair of sony speakers and a box but i will link others speakers if you want to buy them new.
- Amplifier: TDA7492P 2 x 25W with bluetooth integrated. - in the pictures, i used first a PAM 8610 but I highly not recommend it because of the horrible noise and cracks that it makes.
- Battery: 12V 4800Mah, you can buy a bigger or smaller battery if you want, but i recommend a bigger one, those cheap blue batteries are mostly "fake capacity" batteries, usually you get about 30% of the announced capacity. You can make your own battery pack too, but its more complicated.
Speaker case/box: Free, reused PSP intec case
Speakers: Free, reused Sony 2 x 30W 3 ohm home cinema,
you can buy those speakers if you want, or find others on this website:
Remember, 4 ohm speaker a best for a portable use, they need less power than 8 ohm, and the higher the sensitivity is, the louder the speaker gets whitout needing more power ( a 10W 90dB speaker is louder than a 10W 80dB speaker )
In this build I used 3 inch speakers ( 7,6 cm ) , links above include 2,5 inch and 3 inch speakrs but you can of course go smaller or bigger. Bigger speakers can go lower in bass than smaller speakers but be careful to get " full range " speakers, so you dont need a filter for 2 way speaker or more...
- Speaker wire: Free, reused, you can find that pretty much everywhere for cheap or free. You can even grab an old AC wire, cut it and use it as a good quality speaker wire.
Total cost of my build: 16,19 €
( costs may vary with your location and with time )
Step 2: Creating the Bluetooth Speaker
Creating this speaker was pretty easy, just cut the opening of the speaker in the box, I used a circular hole drilling head of the size of the speakers so it will fit nicely. Glue or screw the speaker in, the rest of the components are just sitting there but one the case is closed, they don't move.
Then I connected everything up and secured it in the case.
Its very easy to connect your smartphone or bluetooth device, once its powered on, the amplifier automatically goes in sync mode and connect directly to you bletooth device once paired.
The volume is adjustable via your smartphone and you even have "vol + -" control or "next prev" on the amplifier board but I find them useless.
Step 3: Testing and Finishing Touches.
Once everything is build, you can test it and enjoy it!
I recommend some protection over the speaker to not damadge them while travel , I reused some old 4" speakers grill.
To switch on the speaker, i just need to power on the battery with the integrated switch on it.
I could have make a hole to make it easier to reach and a AUX input too, but im lazy so I didn't make it, feel free to do it :)
For the battery life, I don't really tested it a lot, but for now im happy with it, it can play music at 40-50% volume for more than 10 hours and thats already loud, I assume that at max volume the battery will be quickly done but you will probably never go louder than 70% of the volume witch is really loud.
Thats it! You are done with it!
As you can probably tell this is my first instructable, and english is not my native language, don't hesitate to comment and say what could be better or anything else!
Hope you enjoy it