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Quick Question (USB, IR LEDs)

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  • Quick Question (USB, IR LEDs)

    A quick question for the electrical wizards out there;

    I'm making a friend a neat little IR illuminator for their webcam, and I want to know, would I be able to pull enough power out of a USB port to power it?

    It'll just be 15-20 IR LEDs powered off of a single USB port.
    Doesn't have to be insanely bright, just needs to work.

    Any issues in the design?

    Thanks ahead.

  • #2
    you can get 500mA MAX out of a USB port @ 5 VDC. Depending on how much current your IR leds draw, you might be able to get some powered off the USB bus


    • #3
      I've got no idea how much current they draw.

      I have the following info (probably useless though);

      - 5mm diameter
      - Dark blue lens
      - 940 nm Intensity
      - 20 degrees (this is under a heading of the theta symbol, followed by "1/2")

      That's all the info I can get.
      They're from Dick Smith Electronics (one of Australia's "leading" electronic component suppliers)


      • #4
        A 3 or 5mm uv l.e.d. is 20ma forward current , so thats 400ma , then you need to remember the cam takes power. Maybe use a powered usb hub?


        • #5
          Oh wait you wrote IR , then its about 100ma each. wich is 2 amps for 20.


          • #6
            So I could only power 5.
            Damn, that's not overly useful then. Or is it?
            A powerpack is something like a $20 addition.
            Still cheaper than buying one, the only ones I can find on eBay are for surveillance (and would be too powerful thus flooding the webcam's image sensor with light).

            Would anyone know of any suitable products?