Fiddle – The DIYed Music System

Originally Posted here

Zu ZU ZU ZU ZU UUUU ..BR.BR.CHIK Thats how my old ‘Phillips All in One’ failed a couple of weeks back. It was a pretty archaic piece. All it could do was play Cassettes, Do Radio, Had an Aux In and offcourse the marketed CD Player with a segmented Display. But today most of the music is digital and hence Upgrade was necessary.

I was planning to buy one and browsing the estores but then then Makers Dilemma struck me.

Why Buy? When it can be Built!

And alas! I was fiddling with microcontrollers and SD Cards to make one. But couldnt get to the level i wanted. I wanted one that could:

  • Play MP3s
  • Radio
  • Aux -IN
  • Take SD Cards
  • Remotes will be good too.

Fitting such things in a project would rather be heavenly. I searched online for references and You have it boy! there is one ready to amplify (supply) module from our friends in China that does it all . See this . I had seen this in a Taxi (less formally called Gramin Seva) while commuting to college once, which made me realise that this would certainly be available in India. The next day i was in the market looking for it and I did source it for about 9 $ (INR 500 ) Now all i need to do is :

  1. Decipher the connections
  2. Build a power supply and Amplifier
  3. Find/Repurpose/Build a 2-Component (1-Woof and 1-Tweeter) speaker box
  4. Modify the box to fit all in
  5. Enjoy

Connections were pretty easy as the silkscreen had some references. It basically needs a 5V DC supply that’s the two pin connected on the left for and give stereo output using the 3 of 4 connectors on right (Right, Left and GND) and the last one is for the FM Antenna The Landscape The next part was testing if i will see the blue smoke of death as sometimes they can mess up with silkscreens too. FingersCrossed It worked fine and i was playing things off the USB straight away! USB Reading Now, the power supply and Amplifier. I used the omnipresent 7805 Regulator that could power the module easily as i estimated the current requirements to be around 250-300mA . The supply was going to be 12VDC due to the Amp i was building and hence, a heat sink was necessary. The Amp was build out of ST’s TDA2030 which is a 14W,voltage friendly, High Fidelity (Correct Portrayl of sound without much loss in clarity), Class AB , Mono Amplifier. The Application circuit works charm. So, i assembled them on a single perfboard and was short of one heat sink. I now had to decide. Who needs the heat sink badly? Demo runs showed TDA2030 needs it badly. Now using some thermal glue and nuts and bolts i screwed the heatsink to the TDA2030 and made a makeshift heat sink for 7805 Ortho View Circuit -Front Circuit- Back I heard a strange buzz sometimes in the background which was because of some filtering issues. Adding a snubber (filter) for AC frequencies (50Hz) that was almost gone. Used the 10k and 0.1uF combination. I had an Old but dis functional Column 2 component speaker, we had bought probably 12 years down the line. It was the ideal candidate for the purpose. Now opening and digging i found phenolic pcb with broken and corroded traces. I reworked them and the Woofer was working . (Oh! Yeah) Look at that Woofer I planned to fit the circuit inside the speaker box itself. For that i had to cut a small square pocket in the body for the module to peep out and the other electronics would be inside it. This was a bit more difficult than anticipated. After 2 hours and 2 broken saw blades , I was able to do this. The 2 hour , 2 broken blades cut Now it was assembling time. All Messed up After a few half hours, i got it all working.. No Buzz and all music! Charm Cheers! Rohit

Micro Adjustable Bread-Board Power Supply

I always wanted an adjustable Power Supply that would shell out about 1-1.5A for most of my applications as a hobbyist. But the Space they occupy and the price they come with are always a problem. So, I thought of building a very small power supply that would serve my purpose.

Having worked with LM317 earlier , i choose to build my around it. LM317 can give out about 1.5A according to the datasheets which is more than enough for most of my applications. Now the next hurdle was to make it as small as possible. The schematic is given below:

Schematic

Schematic

It took a couple of design iterations to make it suitable for a single sided board and i was finally able to come up with a very small one.
The size i was able to build was 3cm X 2.5cm with all components included on board.
Before making(etching,soldering) it was necessary for me to do some 3D- Rendering of the PCB so that i can have a better Idea of how the final board will look. I used Google SketchUp for the same. The Isometric image is provided below:

3D Rendered Board

3D Rendered Board

 

The Final Rendered Image

The Final Rendered Image

It took me a while to make the board as the Bourns Pot i had was faulty and the local store took some time to get it for me.The board has a heat-sink for LM317 glued using processor heat glue to dissipate heat.There is also a small switch that i managed to squeeze on the board and a diode..just in case you had polarity issues.

The completed board that i built looked like this:

Small and wastes no holes

Tiny and wastes no holes

This is the demo picture showing the output as 2.9V at a 8V input from a standard AC adapter.

In Action :)

In Action 🙂

Cheers and Regards,

IndianTinker 😀