Other than some simple flashing LEDs this is my first Arduino project. I came up with an idea on the fly in this thread actually
) to build something that would play sounds and possibly flash LEDs when someone walks up to it or by it. I thought it might be difficult at first but this past weekend I decided to give it a go.
I started out with a cheap mp3 player:
The way it works is to turn it on you press and hold play for a little over a second to turn it on. It takes a few seconds to power up. Then it has all the standard buttons you would expect. Forward/Back, Volume, etc... I figured if I could bypass the play and forward button I could control it with the Arduino.
So I ripped it apart:
And lucky for me you can see in the next pic the 2 far right buttons are the play and forward track buttons. If they had been next to the battery it would have been a lot tougher.
Looking at the buttons I saw some open contacts that were not being used. Measured with a milti meeter to make sure they worked and they did.
I took some magnet wire (24 gauge I think) cause it was tiny and flexible and did my best to solder to the tiny contacts.
It took a lot of time and the solder joints were not very strong. 2 wires fell off and had to be reattached. Finally I bent them down and taped them in place to reduce the stress on them.
Even after this the far left one fell off and had to be redone but I think they're all pretty good now.
I hooked it up to a breadboard with buttons to test it out. WARNING: Very boring video <a href="http://www.biocow.com/arduino/mp3hack/1.MOV
" target="_blank">here</a>. (Takes a bit to load.)
Next I moved to the Arduino with protoboard. Got some 2n2222a transistors and various resisters and tried to hook it up but I couldn't get it to work. I hooked up an LED and the Arduino would make that work but I couldn't make them switch the mp3 player on or forward the tracks. It dawned on me later that I wasn't using a common ground and that was probably my problem. But I figured finding ground on the player would be difficult. Instead I opted for relays. I went to my local electronics surplus store (Halted Electronics) and picked up these relays.
Got it wired up right and it worked flawlessly.
I wrote a little code and got it running in a loop:
Forward a random # of tracks
I had also ordered some Sharp IR sensors so next I plugged that in and added some code. I honestly thought that would be the hardest part but I had that working in about 10 minutes.
Here is the whole setup:
I'll post the code in the next post.