Musicbox stuff: relay, capacitor, amps
For my musicbox mobile mp3 player, I needed a way to turn it on automatically when the car turns on. That meant I needed a relay. I bought one from mpja.com for 29 cents and installed it inside a little Radio Shack project box. I also had a problem with my musicbox: if you turned the system on in the car without actually starting the engine, and then once it was playing, you started the engine, it would reboot. So I installed a giant capacitor in hopes that it would fix that, but it didn't. Oh well. In the process of installing the cap, I had to move my amps around on the board they're mounted to, so I included some photos of that at the end.
 This is the relay itself, it's tiny, only about an inch tall. photo courtesy of mpja.com. |
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 the blue wires are for the 12V control signal; when applied, that signal shorts the red wires to provide the high-current source to the system. |
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 it's really hard to solder wires that big when they're bent and you only have 2 hands. cable ties made it possible. |
 and without the cable ties, the solder joints would almost certainly break because of the pressure from the wires pulling away. |
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 a 1 farad capacitor... still doesn't provide enough capacitance to hold the voltage at 12V during ignition, unfortunately. |
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 I mounted the cap label-down because it looks a lot cooler than that cheesy label. |
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