# How I saved an MP3 player



## JeffHaas (Sep 7, 2010)

I got a free mini MP3 player at a conference last year. It looks like one of these new:










Unfornately, the battery died after less than a year (in the middle of a run!) So I opened it up to see if I could use it somehow. The insides look like this:










And the rest of it:










That square thing in the lower-left is the battery, just about the size of a quarter. I left it connected and charged it up, then used my multimeter to see what it put out, which is about 4.5 volts - for about a minute, then it dies again.

[Continued next post...]


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## JeffHaas (Sep 7, 2010)

So I soldered some wires to the pads on the back and mounted it on a small piece of perfboard, and connected the wires to buttons and hooked up the battery inputs to a terminal block, like so:










I didn't remember to take any pictures of the back before I had it all attached to the perfboard, sorry.

Anyway, it still works great and puts out good sound. However, one of the annoying things about it being so cheap is that there's no screen, so no way to know where you are in the playlist. It will get to the end of all the tracks and start over automatically, so I'm going to use it for background sound effects somewhere in the haunt this year. It should run for days on three AA batteries.


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## CoolDJTV (Jun 28, 2011)

cool
if you only put one sound on it and connects the [Play] terminal to a relay then to a trigger mat, that could work really good for the difficult task of adding sound to a prop with out expensive prop controllers


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## JeffHaas (Sep 7, 2010)

That would work. You could also use one of the Electronics123.com modules in the same way, if you don't have an MP3 player with a dead battery to sacrifice.


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## BioHazardCustoms (Aug 5, 2009)

Nice save, Jeff!


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## corey872 (Jan 10, 2010)

Thanks for sharing the Zombie mp3!

Does it also take power from it's usb port? Was wondering if it would also be possible to leave the player intact and just cannibalize an old usb cable for the connection between the battery pack and the mp3 player?


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## JeffHaas (Sep 7, 2010)

I just tested it...it does take power from the USB port. So I guess I could have chopped up an old USB cable, hooked in 5V and had it working that way. Oh well!

However, I will say that with these new buttons, it's much easier to use. The original buttons are the cheapest possible - little round pieces of foil stuck to a piece of tape, lined up over spots on the circuit board, and concave so they "click" when you press on them. You can see them in the lower right corner of one of the pictures, they look like the five-spot on a die. So it didn't always respond properly when you pressed a button.

The buttons I used cost 25 cents each from Jameco, which would totally blow the materials budget on the original!


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## JeffHaas (Sep 7, 2010)

CoolDJTV - I just checked it again, it turns out that it won't work for triggered sounds. Once you press [Play] it plays continuously until you press [Play] again to pause it. When it gets to the end of the entire list of tracks, it starts over at the top again.

So it will only be good for continuous background sounds. You could make a controller that would start playback and then wait until the sound was over and pause it, but that's too much trouble. Just get one of the Electronics123.com boards, which are set up to play a single sound when a button is pressed.


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## The_Caretaker (Mar 6, 2007)

I'm doing the same thing with a cheap MP3 player I bought on ebay for a couple of bucks. The only thing is that a lithium flat pack battery would only put out about 3.8 volts. You may be stressing the electronics at a higher voltage.


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## JeffHaas (Sep 7, 2010)

Then I'll just use it with batteries that are somewhat run down.


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## BioHazardCustoms (Aug 5, 2009)

I wonder if you could use an old cell phone charger (120 VAC to 3.5-4 VDC) to run it? I mean, of course, if you wanted to have it wired. If you're like me, you probably have a few lying around somewhere, doing nothing.


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## JeffHaas (Sep 7, 2010)

That should work, especially if it has a mini-usb connector - that's how I used to charge up the battery. If you don't have one of those then just cut off whatever the oddly-shaped charger connector is and hook up to the terminal block. I'd also make sure to figure out which wires were positive and negative with a multitester first.


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