Hi,
In 2 months I'll be going on a snowboard trip with my university and I'd like to take along some MP3 players. I'll probably take 2 with me, my iPod, for normal listening and a Creative Rhomba, which I will buy for cheap from a friend (it was broken and I had to do some soldering and glueing to get it back in shape, but it's just as new now). I'll use that on the snow, because it uses Flash memory it won't be as easily to get broken as the iPod. And I certainly don't want to crash with a $500 MP3-player in my pocket, so taking the iPod with me while snowboarding is out of the question.
Of course the batteries will get empty. I have a charger for the iPod, but I don't have one for the Rhomba, so I was thinking of making my own charger for it.
I already ordered some USB A female connectors so that I can plug in the Rhomba's USB cabel into it, but I don't know if I need to add anything special to the circuit. Do I just construct a 5V 1.5A power supply using an LM317 or do I need more advanced stuff like a Li-Ion charger chip? Will the Rhomba take care of the charging process or is it the charger?
I guess it's the Rhomba, since I don't think the PC handles the charging when the Rhomba's connected to it, but I'd like to be sure before I blow the poor thing up.
Btw, the exact thing I want seems to be for sale: here, but of course there isn't any info about the circuit they use. (Oh and no, I won't buy it, without even looking at the price I know it will be ridicilously expensive for what it is.)
In 2 months I'll be going on a snowboard trip with my university and I'd like to take along some MP3 players. I'll probably take 2 with me, my iPod, for normal listening and a Creative Rhomba, which I will buy for cheap from a friend (it was broken and I had to do some soldering and glueing to get it back in shape, but it's just as new now). I'll use that on the snow, because it uses Flash memory it won't be as easily to get broken as the iPod. And I certainly don't want to crash with a $500 MP3-player in my pocket, so taking the iPod with me while snowboarding is out of the question.
Of course the batteries will get empty. I have a charger for the iPod, but I don't have one for the Rhomba, so I was thinking of making my own charger for it.
I already ordered some USB A female connectors so that I can plug in the Rhomba's USB cabel into it, but I don't know if I need to add anything special to the circuit. Do I just construct a 5V 1.5A power supply using an LM317 or do I need more advanced stuff like a Li-Ion charger chip? Will the Rhomba take care of the charging process or is it the charger?
I guess it's the Rhomba, since I don't think the PC handles the charging when the Rhomba's connected to it, but I'd like to be sure before I blow the poor thing up.
Btw, the exact thing I want seems to be for sale: here, but of course there isn't any info about the circuit they use. (Oh and no, I won't buy it, without even looking at the price I know it will be ridicilously expensive for what it is.)
.
In case someone's interested, you can find the schematic and PCB layout here.
I'll probably make the PCB this Sunday and I've already got all the parts I need, so if the PCB comes out OK (I seem to have some problem with getting good PCBs lately), the circuit should be finished the same day and then I'll upload pictures.
I'll probably make the PCB this Sunday and I've already got all the parts I need, so if the PCB comes out OK (I seem to have some problem with getting good PCBs lately), the circuit should be finished the same day and then I'll upload pictures.
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