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I want to run the ps eye camera for my raspberry pi model b+. It is rated at 5v 500 mA . The question is , is it wise to directly connect it to the provided usb? I am using the pi to make something portable, so using a usb hub will not be possible. I know that I can just pull power from the same source as the one powering the pi, but I would like to know if its possible to connect something that requires that kind of current.

Also(Off topic) The Pi has mounting holes. I am using a breadboard for my project. I want to know the name of the plastic tubes that come that allow you screw things. The idea is to place the PI a few inches above the breadboard. Do any kinds of mounts come that allow you to screw things(that are breadboard compatible)?

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    Technical term for those is "standoffs". – Gerben Aug 3 '14 at 17:26
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    i would have upvoted had this been an answer – harveyslash Aug 3 '14 at 17:36
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According to this and this Raspberry Pi B+ has 600mA current limiter and it can be changed to 1.2A (1200mA) by software (in config.txt file).

And you don't have to use big and ugly powered USB hub to put more power into your USB device. You can split USB cable or make some adapter and connect +5V device line directly to +5V from your power supply.

I have something like this:

enter image description here

My power supply is a bit diffrent, but it has two USB outputs too.

You don't need this with B+ model, but it's good to know.

  • I had thought of this, but even then it increases wiring – harveyslash Aug 2 '14 at 3:31
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    You may be introducing ground loop with that USB cable. Not good for WiFi and definably not good for Audio! – Piotr Kula Aug 2 '14 at 14:57
  • can you please ellaborate about what you are saying ? – harveyslash Aug 4 '14 at 19:10
  • @harvey_slash just google for "ground loop" and read what is this. In my case, with short (1m) cables it doesn't matter. It works, no problems with UMTS. I haven't tried this with WiFi because my wifi works on 100mA output without problems, so no need for weird wiring. – Kamil Aug 4 '14 at 22:32
  • I just asked about ground loop problem here: electronics.stackexchange.com/questions/124039/… – Kamil Aug 4 '14 at 22:55
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The USB standard dictates that all USB 1.x and 2.0 shall be able to deliver 500 mA, so you should be fine - as long as you input enough power into the pi, of course. The b+ uses 600 mA, so you power supply should be able to feed at least 500+600=1100 mA, and some for extra for good measure.

But if you need a portable low power solution, maybe you want to have a look at the Model A+.

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