USB 12v switching

by gudenau on Wed Jan 23, 2013 7:07 pm

I would like to switch 12v dc when the usb gets powered (while still providing some to the device with usb), how should I do this?
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Re: USB 12v switching

by Zener on Wed Jan 23, 2013 7:40 pm

I think we need a little more details on what you want to do.
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Re: USB 12v switching

by gudenau on Wed Jan 23, 2013 7:42 pm

What more do we need, like that the usb is going to the same device as the 12v dc?
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Re: USB 12v switching

by Zener on Wed Jan 23, 2013 7:48 pm

Maybe a sketch or drawing would help. But there are many other great minds here who might know what you need.
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Re: USB 12v switching

by gudenau on Wed Jan 23, 2013 11:33 pm

Oaky, I will get a scetch up as soon as I can, it should be up soonish, this is from my iPod and I am about to goto bed, then school, so...
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Re: USB 12v switching

by gudenau on Thu Jan 24, 2013 6:19 pm

Got it.
Image
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Re: USB 12v switching

by adafruit_support_mike on Thu Jan 24, 2013 8:06 pm

How much current do you want to draw from the 12v line? If it's a little, you can use a transistor. If it's a lot, you'll want a relay.
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Re: USB 12v switching

by gudenau on Thu Jan 24, 2013 9:24 pm

I am powering a old hard drive, from when 64gb was top of the line.
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Re: USB 12v switching

by adafruit_support_mike on Sat Jan 26, 2013 1:02 am

Power consumption for hard drives is usually around 10 Watts, so call it an amp of current.

You can probably use a mosfet like this one: http://www.adafruit.com/products/355
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Re: USB 12v switching

by gudenau on Sat Jan 26, 2013 1:13 pm

Thank you, this has helped.
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