Powering USB devices from a firewire port?

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Powering USB devices from a firewire port?

Basically I'm going away to Canada soon, and rather than carry 2 iPod chargers I was wondering whether it would be possible to charge my shuffle from a Firewire port, as my 3G doesn't charge over USB.

So what's the easiest way to loose 7v from the supply?

TOM

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Oh, and my phone also charges

Oh, and my phone also charges from USB... so it'd save taking that charger too!

TOM

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well with my humble knowledge

well with my humble knowledge methinks u could be a cable as follows (but i dont really know the details)

1 a male FW plug
2 a resistor/transformer wired to the power from the FW plug and the to the power on the USB
3 a female USB plug

couldnt u just leave the shuffle at home [;-)]

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A 7V linear regulator and a h

A 7V linear regulator and a heatsink?

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Re: well with my humble knowledge

well with my humble knowledge methinks u could be a cable as follows (but i dont really know the details)

1 a male FW plug
2 a resistor/transformer wired to the power from the FW plug and the to the power on the USB
3 a female USB plug

couldnt u just leave the shuffle at home [;-)]


It's DC so a transformer won't work. And dropping voltage using a resistor isn't ideal, as IIRC the charging current changes during the charging cycle. A voltage regulator is looking good, just have to find one that'll give a nice 5v output.

TOM

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Re: well with my humble knowledge

well with my humble knowledge methinks u could be a cable as follows (but i dont really know the details)

1 a male FW plug
2 a resistor/transformer wired to the power from the FW plug and the to the power on the USB
3 a female USB plug

couldnt u just leave the shuffle at home [;-)]


It's DC so a transformer won't work. And dropping voltage using a resistor isn't ideal, as IIRC the charging current changes during the charging cycle. A voltage regulator is looking good, just have to find one that'll give a nice 5v output.

TOM

I know it goes against the hacker spirit and all that, but...can't you just use your iBook to charge up these? I'm assuming it's coming with you, and they tend to have USB on them.

It's more because I'm curious than anything.

-BDub

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Re: well with my humble knowledge

I know it goes against the hacker spirit and all that, but...can't you just use your iBook to charge up these? I'm assuming it's coming with you, and they tend to have USB on them.

It's more because I'm curious than anything.

-BDub


I wasn't planning on taking it originally, as it would be an extra risk and I would have to carry it about the whole time (I'm not too keen on leaving it in the hotel). Plus the backlight went on the screen yesterday, so I doubt that I will be able to get it repaired in time anyway!

TOM

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Is it still under warrenty?

Is it still under warranty?

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Re: Is it still under warrenty?

Is it still under warranty?

Nope, out by about a week ::)

TOM

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