Tuesday, 14 August 2012

Powered USB Hub - £2


 I bought a couple of these little USB 2.0 hubs for £1 each in PoundWorld intending to adapt them to be powered hubs for use with RaspberryPi computers.  Alan here (http://pihub.blogspot.co.uk/2012/06/raspberry-pi-power-supply-and-powered.html) beat me to it, but I wanted to give it a go with a flying power socket.  As usual, heat-shrink sleeve comes in to save the day.

I didn't like the original USB lead and plug so I bought a USB-to-Micro USB cable (again for £1) and cut it in half.  One end goes to power the RPi and the other is the input USB.

The input USB has only 3 connections made, the red power wire is cut short and ignored.  I did connect the ground (GND) wire though because the purist in me doesn't like the idea of floating grounds (blame my MSc).   The output for power to the RPi via the micro USB plug only has the GND and +5v connections made and the other 2 signal lines were chopped short and ignored.

The power input was made from a DC power socket salvaged from an old lead for a dead PDA and with some black heat-shrink it looks quite professional and hard-wearing.  I have a small hoard of 5v 2A power supplies that were for various long-deceased gear and one of these is powering all this.

And it works like a dream!

3 comments:

  1. I like it -- I agree it looks neater than the original! I should get some of that heat-shrink: I always end up wrapping round tons of electrician's tape, which as you can imagine looks terrible.

    A couple of folks on the Pi forums told me I should leave the ground connected. I would go back in there and reconnect it, but I haven't had any problems with it as it is, so haven't had the impetus.

    I've got a crate full of old power supplies, too. Extremely useful to have a selection at hand. Never know what your next project is going to call for!

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  2. Heat shrink is the best thing ever invented, I use it all the time. CPC sell packs of assorted 3:1 and 2:1 sleeve and I keep some of that handy in the workshop. Just remember to put the sleeve on before finishing the soldering. I've lost count of the number of times I've had to re-do something to get the sleeve on before shrinking it!

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  3. nice job (and Alan's too). Am about to create my own variant but thought I'd run it passed you both first. My idea is to cut into the sleeve of the output usb lead an inch or two from hen plug end and splice onto the +5v and GND wires a micro usb to usb type B lead which again I will have spliced into about 5 inches from the microusb end of it (i.e. enough to run round to the other side of the Pi to power it) and join the two 5v and gnd wires of each together. The idea being that micro usb end attaches to the Pi to power it and the USB type B end will plug into one of those many USB wall wart chargers one tends to accumulate - I have a 2A rated one kicking around at the moment. I think this would therefore power the hub and the Pi. I might only splice into the hub end of the power wires on the hub input lead to avoid backpowering the hubs two usb output ports. If it works it avoids me doing any butchering of the hub itself. I guess I could do the same with two usb leads of whatever type/gender was needed and therefore make it work with any other unpowered hub that had a non-captive input lead (seen a belkin one that has a usb type A socket for output for example so I would use a micro usb to type B and a usb type A lead to give a flexible solution. Moreso with the addition of a few usb type adapaters?

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