Music Box

On March 6, 2011, in Electronics, Misc, by Cmc

I just finished a little nice project that is a sweet gift for anyone. If one opens the cover of the pencilbox it’ll start playing a tune that repeats itself until it is closed again.

Basically it has just 4 main components: power supply, AVR-uC, SD-card and the speaker. Here I’ve connected the AVR output straight to the speaker to get nice sound. The AVR works by reading the WAV PCM file from the SD card and shooting the info to PWM outputs of pins. I’ve added a resistor and a capacitor for the filtering and smoothing purposes and what I get out of it is actually an astonishing sound quality. If I add the fact, that AVR offers only a few mA on outputs and runs on 3.3V because of SD card, then it makes it even nicer. The sound is loud enough for my application and when I did a test run, I used a huge 8ohm speaker that was actually too damn loud for my purpose.

I had a lot of fun building it, and am really sorry for not using any pcb-s, but this is the first prototype. If I would make a pcb for it, I could get a system that would fit virtually anywhere.

Also I made a video, but I’ll upload that to YouTube soon and post EDIT to here.


Here is the video.

Stay Frosty!


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