jasperthedog
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Cheap wifi dongle that works directly?

Fri Jun 01, 2012 7:10 pm

Hi, I'm expecting my Rpi within a couple of weeks, and all I now need to get it up and running nicely would be a wifi dongle. However, since I am a massive newbie when it comes to programming etc..., I would like one that would work straight away (i.e: no complicated or slightly complicated tinkering needed). Also, being relatively skint, I can only afford one costing maximum eleven pounds (i can maybe stretch it to twelve :) ). I would be extremely grateful for any suggestions, preferably from people who have first hand exeperience rather than hearsay, but any advice is welcome!

bredman
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Re: Cheap wifi dongle that works directly?

Fri Jun 01, 2012 8:45 pm

I personally use an RT2070 (http://www.dx.com/p/24688) It is not beautiful or very small, but it is cheap $9 including shipping worldwide.

Like all WiFi devices, you will probably need a powered USB hub.

There is a bit of setting up needed (see http://wiki.debian.org/rt2870sta) but there are lots of helpful people here if you get stuck.

jasperthedog
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Re: Cheap wifi dongle that works directly?

Fri Jun 01, 2012 8:49 pm

Thank you bredman, but I was just wondering: since your dongle seems to come with a cd, how would you install it on a pi (I know I might be being thick here)?

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mahjongg
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Re: Cheap wifi dongle that works directly?

Fri Jun 01, 2012 10:40 pm

The only WiFi dongles you can expect to work "out of the box" (that is connected to an externally powered USB hub, obviously, as no WiFi dongle I know is a 100mA device) is one that has its driver incorporated into the kernel of the linux distro you are using!
Use the WIKI to find out which those are!

bredman
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Re: Cheap wifi dongle that works directly?

Sat Jun 02, 2012 11:02 am

WiFi devices normally come with a CD which include the drivers for Windows PCs.

In a Windows PC, you insert the CD and open a file such as setup.exe

In a Linux PC, you don't need a CD. You normally enter a command such as
sudo apt-get install firmware-ralink
or
sudo apt-get install firmware-realtek

Note the above commands are only valid for Ralink or Realtek products, the most popular ones. The exact command will depend on the manufacturer of the WiFi device.

If you're really lucky, the driver may already be part of the Linux kernel, which means you don't need to install the driver at all.
Last edited by bredman on Sat Jun 02, 2012 11:07 am, edited 1 time in total.

bredman
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Re: Cheap wifi dongle that works directly?

Sat Jun 02, 2012 11:05 am

I should have pointed you to the list of WiFi devices which have been tested with Raspberry Pi
http://elinux.org/RPi_VerifiedPeriphera ... i_Adapters

raj
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Re: Cheap wifi dongle that works directly?

Thu Jun 07, 2012 10:45 pm

So, looking at the web page mentioned, it appears as though the Micronet SP907NS has supposedly been known to work when directly plugged into the R-Pi. Unfortunately, this device isn't really very available. I can't find anywhere to purchase it in the US. Does someone know of a way to get hold of one of these in the US?

The reason I'm pursuing this as opposed to some other, is that I'm trying to put together a small HTTP server running on the R-Pi which would be wired into house wiring, would be on the network via WiFi, and would be dropped inside the wall. I'd really like to avoid extra power going to a hub, etc., if possible. I'm open to wiring in a small hub, if that's the only way, in which case I'd be interested in small powered hubs.

Any ideas?

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jbeale
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Re: Cheap wifi dongle that works directly?

Thu Jun 07, 2012 11:21 pm

If you have no other USB devices, instead of a hub you can use a USB "Y" cable to draw power from both USB ports, that doubles the available current from 100 mA to 200 mA.

The cable would look like this:
Image

If you're not afraid of warranty-voiding solder jobs, you can do the same thing without an extra cable, by wiring together the two +5V pins on the USB ports on the board (so the two fuses F1, F2 are now in parallel).

raj
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Re: Cheap wifi dongle that works directly?

Thu Jun 07, 2012 11:26 pm

Hmm.. Interesting idea! So, it doesn't hurt anything to directly connect the two USB ports together like that? I'd certainly be willing to give that a try. I'm also not above soldering. :)

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jbeale
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Re: Cheap wifi dongle that works directly?

Fri Jun 08, 2012 12:54 am

Well, remember that USB "Y" power cable, or the suggested board mod, just connects the two USB +5V power lines together that already come from the same point (the R-Pi +5V power rail). You are just combining the output of the two fuses F1,F2. When they are in parallel you get double the current draw for any given voltage drop.

You are not shorting together the two ports' USB data lines; that would be bad!

Personally, on my board I'd also be willing to just short across those F1,F2 output fuses because their safety value is not obvious to me (since there is still the input fuse F3). But the R-Pi designers obviously thought they should be there, so I'm not recommending that to others, and particularly if you are mounting the R-Pi inside a wall (is that really the plan?)
Last edited by jbeale on Fri Jun 08, 2012 1:01 am, edited 1 time in total.

raj
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Re: Cheap wifi dongle that works directly?

Fri Jun 08, 2012 12:57 am

Right! That makes sense. Thanks.

raj
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Re: Cheap wifi dongle that works directly?

Sun Jun 10, 2012 8:32 pm

Sorry, I see I didn't reply to the other part of your question. Yes, the plan is currently to put the entire unit inside the wall. It just doesn't produce that much heat to be an issue, I don't think. The most heat would come from the 110->5v transformer.

I'll need both USB ports, since one will be for WiFi and the other will be connected to a USB->serial converter which will connect to the spa controls interface unit. So, I'm thinking maybe the safest way to go would be something like this:
<http://www.amazon.com/2-Port-Travel-Cha ... B002FFG6JC>
then use one of the ports to power the Rasp-Pi while the other port helps power the WiFi dongle. I can even wire in a switch on the Rasp-Pi power line in order to easily reset without having to fish it out of the wall. It'll be a web server totally hidden in the wall, controlling the spa and connected to the net via WiFi. Forward port 80 through the house router and you have spa web page control world-wide (with authentication, of course).

normal
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Re: Cheap wifi dongle that works directly?

Fri Jun 15, 2012 9:08 pm

mahjongg wrote:The only WiFi dongles you can expect to work "out of the box" (that is connected to an externally powered USB hub, obviously, as no WiFi dongle I know is a 100mA device) is one that has its driver incorporated into the kernel of the linux distro you are using!
Use the WIKI to find out which those are!
I have a RTL8712SU card meaning I need to compile kernel and drivers every time kernel updates. Right now the r8712u driver on various sites for RPi doesn't work with the newest firmware/kernel and every time it updates apparently I need to wait 7 hours just to compile a whole kernel just to get one driver out of it. The wiki says this driver is built into Fedora and Arch but isn't there a way to get this built in for future Debain releases or is it just something I should have known better about linux? Either way I think it will be very discouraging for the future buyers if they have to wait 7 hours every time something updates just to make their wireless work if they happen to get a wifi adapter that isn't perfectly working for linux and needs to compile a driver.

If not that, can there be someone who keeps track of kernel upates and compiles a new r8712u so we don't all ahve to wait 7 hours every week and do nothing else with our RPi? Its either that or people have to take chances and possibly buy more than one wifi apadter for their RPi.... By the way my particular adapter works out of the box with XBMC.

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