raven_squire
Posts: 23
Joined: Fri Jun 29, 2012 8:39 am

USB Y Cable.

Sun Aug 05, 2012 8:28 am

Hello,
I have been having trouble setting up my Netgear WNA 1100 WI Fi dongle.
I want to eliminate a lack of power as a potential cause of failure as I read that the WNA1100 is power hungry. I have half a dozen USB hubs but none are on the verified preherisals list (they don't seam to be easy to track down).

Can I use one of those USB Y cables (E.G. Ebay Item number: 150634221332) and plug one of the male plugs straight into the PI and the other into a USB wall wart? Would this ensure that there is enough power for the Wi Fi Dongle? (I ask as the descriptions for these seem to suggest that they go into a second usb port from the same device)

If it would work can I make my own (I dont want to wait for the slow boat from china) by splicing up two USB extension cables up and connecting Pins 1 and 4 from one male plug and 2,3 from the other to the femail end?

Thanks in advance!!!

CCitizenTO
Posts: 83
Joined: Sun May 20, 2012 2:14 am

Re: USB Y Cable.

Sun Aug 05, 2012 5:49 pm

Well WiFi Dongles are some of the higher powered devices you can plug into a USB port so eliminating the lack of power is a good idea.

I would reccomend using one of the USB Hubs you have on hand. No doubt at least ONE of them would work. They may not be on the verified list but you might just be able to add yours to the list.

That said the USB Y-Cable is really only used to power the RPi from a Powered Hub. This is because by specification a USB port will only deliver 500mA of current (at 5V). Thus to get enough juice to power the RPi you need to pull current from two ports to get up to 700ma-1A it needs to work. You do this by monopolizing 2 ports on the hub to power the Pi (the two male ends usually standard USB) then sticking the MicroUSB end into the RPi to power it.

The RPi's native ports are underspec. They only deliver 100mA and some people say they only deliver about 4.4V rather than a full 5V. Keyboards and Mice work fine with these but most devices like Wifi Dongles might cause probems. Which is why powered USB hubs are reccomended peripheral to pick up with your RPi.

Getting a wall wart with more amps isnt going to help because the Pi only draws a certain amount of power and the USB ports are underspec. You need a powered hub to eliminate power problems as the issue.

raven_squire
Posts: 23
Joined: Fri Jun 29, 2012 8:39 am

Re: USB Y Cable.

Sun Aug 05, 2012 7:37 pm

Thanks for your help. :D :D :D

CCitizenTO
Posts: 83
Joined: Sun May 20, 2012 2:14 am

Re: USB Y Cable.

Tue Aug 07, 2012 3:39 am

No problem...

I like to help out when I can.

underwood
Posts: 7
Joined: Tue Aug 07, 2012 5:48 pm

Re: USB Y Cable.

Tue Aug 07, 2012 5:57 pm

The EDIMAX EW-7811UN works without a USB Hub on the RPI USB-Ports.

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