chrisULM Posted February 27, 2008 Share Posted February 27, 2008 I've got a crappy little mp3 player from Walmart that runs off one AAA battery. I use it primarily for listening to podcasts while i drive, since it shows up like a regular usb thumbdrive in Linux (i'd have to reboot into windows to put podcasts on the zune). The only problem I have with it is that the only way to power it is off the one battery. It doesn't have any sort of power adapter available and its a pain to keep recharging the AAA battery to keep it going. I'm thinking of a way to us the power from my car's battery to charge the unit. I have a power adapter in the car that powers usb devices (it measures at 5.2v w/ my multimeter). I figure I could just splice up a usb cable, and connect the ends of the cable to the + and - ends of the player to power it. Of course I'm sure I'd need some sort of resistors or something so I dont fry the mp3 player. Heres a drawing to clear it up a bit. http://img184.imageshack.us/img184/5706/mp3bg0.gif[/img] I have a few questions 1) Would this even work or is this completely stupid? 2) I measured the voltage of a AAA battery with my multimeter to get the 1.25v. Would this number be accurate for the mp3 player or could it somehow draw more or less? 3) Assuming my numbers are correct, what kind of resistors would be needed to bring the 5.2v down to 1.25v? As you can see I dont know too much about these types of projects, so any help you could give me would be very helpful. Quote Link to comment Share on other sites More sharing options...
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