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Control USB power

Hello,
 
I use the USB port as power supply for a LED. Is there a way to turn on/off the power of the USB port using Labview?
 
 
Thanks
 
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Message 1 of 10
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OK. I'll ask: Why would you want to do this? This is a fundamental motherboard operation in terms of controlling the USB power. Perhaps an alternate solution would be better? What are you trying to do?
Message 2 of 10
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I'm developing a portable low-cost setup for fluorescence visualization. I need to use a blue LED (continuously) and a green LED alternatively. I want to use the power of the USB port instead of an external battery. First I thought to switch on/off the green LED using a mosfet transistor controlled by the serial port but the current/voltage characteristic avoid this solution. So I thought that maybe there is an easy way to control the USB power with Labview.

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Message 3 of 10
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Switching off the USB power is not a good idea. Doing so would disable all USB devices, like a keyboard and/or mouse, as well as anything else that's plugged in. I could suggest using the parallel port (if you have one), but you need to keep in mind that if you wire up something incorrectly you'll likely fry the motherboard. You can also get USB-based IO interface products which would suit your needs. Do a Google search and you'll find a bunch. For example:
http://www.eidusa.com/Interface_Boards_USB_6_IO.htm
http://techrepublic.com.com/5208-11196-0.html?forumID=51&threadID=176185&messageID=1791154
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Message 4 of 10
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Thank you for your help. I'll look for a USB-based IO interface products.
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Message 5 of 10
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I have experience with the IO warrior from codemercs. There a kits available that have place for custom circuitery and it is powered by the USB bus. Big plus to me is that there are working LV drivers available.Smiley Very Happy


Message Edited by andre.buurman@carya on 12-11-2007 08:32 PM
Regards,
André (CLA, CLED)
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Message 6 of 10
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another link:
------- LabVIEW 2009, So Easy, Even a Therapist Can Do It -------
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Message 7 of 10
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Hello,

I would suggest using a National Instruments USB 6008.  I have attached the product page below.  Please view the data sheet for this product.  If you would like I can also help connect you with an Internal Sales Representative if you post an email or phone number.  If not, also feel free to contact National Instruments yourself.  I have linked a page with our sales and tech support numbers. 

NI USB-6008

Contact NI

 

Samantha
National Instruments
Applications Engineer
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Message 8 of 10
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robin84 wrote:

I'm developing a portable low-cost setup for fluorescence visualization. I need to use a blue LED (continuously) and a green LED alternatively. I want to use the power of the USB port instead of an external battery. First I thought to switch on/off the green LED using a mosfet transistor controlled by the serial port but the current/voltage characteristic avoid this solution. So I thought that maybe there is an easy way to control the USB power with Labview.




if you were ready to invest into a home built solution using mosfets, there are much simpler solutions, involving a 5V from the serial or parallel port: 5V power supply on a pnp transistor. this will drive any LED you trow at it.

otherwise go for a USB6008 as proposed. very simple, cheap and robust.

-----------------------------------------------------------------------------------------------------
... And here's where I keep assorted lengths of wires...
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Message 9 of 10
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If all you need to do is turn LEDs on and off, then a USB6501 will let you turn on and off 24 LEDs all day long without too much trouble.  It is also $60 cheeper than the USB6008.  Of corse, the USB6008 is probably a much better deal depending on if you need the analog inputs/outputs.
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Message 10 of 10
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