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Author Topic: Best USB wireless stick for sheevaplug?  (Read 2608 times)
ljones
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« on: March 14, 2010, 05:42:41 AM »

Hello all Smiley !

A long time ago I was trying to figure out how to get my sheevaplug to work via USB wireless. I managed to do this originally with a netgear WG111V2 (there's a thread about this here - http://plugcomputer.org/plugforum/index.php?topic=624.0 ) . Eventually I replaced that adapter with an Alfa networks wireless adaptor which seemed to work better.

Unfortunatly though the idea to use the sheevaplug over wireless still isn't 100% . The original problem with the WG111V2 was that it would drop the connection (if it would even connect at all) plus it ran very warm. The alfa networks device (actually an alfa networks AWUS036H) works better but it is still extremely prone to random disconnects and dropout. In fact I eventually ended up (with help) writing a script like this;

Code:
#!/bin/sh
#
# Tidied up script which checks if the sheevaplug is conencted, if it isn't
# then a connection is made for five attempts, and if it fails on the fifth
# go then the sheevaplug is reset.
#
# Uses a file called "count.var" to store the variable count into a file
#

# First check to see if the file count.var exists, and if not - make it!
if [ -e "count.var" ]
then
 :                      #  The file exists, so no need for any action
else
 echo 0 > count.var     #  No file, so put 0 into the file count.var
fi

# Read count.var and put it into variable count
count=`cat count.var`

# Check to see if the connection has been lost
if=wlan0
if iwconfig $if | grep -q Not-Associated ;
then
 :                      # Uh oh, lost connection so ....
else
 count=0                # We're connected so set count to 0
 rm count.var           # Get rid of count.var
 exit
fi

# Since we're not connected carry on....
# Has the counter reached 5 yet? If so, reboot.
if [ $count -eq 5 ] then
 count=0                # Set counter to 0
 rm count.var           # Get rid of count.var
 shutdown -r now        # Not connected :-( so restart sheevaplug
 exit                   
fi

# Counter hasn't gotten to 5 yet, so add 1 to count
count=$(($count +1))

# Save it to count.var
echo $count > count.var

# And try to reconnect ....
iwconfig $if ap auto

....because it drops out and disconnects so much. Pinging it also shows it is missing pings as well! So does anyone here know of a good stable usb wireless device that will work with the sheeva without all the dropout and disconnects?

Also one more thing -- I use the service noip and in order for it to function a small program ( noip-2.1.9-1 , http://www.no-ip.com/downloads.php ) is needed to make it work. I can compile this to run ok on a normal PC but does anyone have a version compiled for the sheevaplug at all?

BTW I have enclosed a (pretty crude!) diagram showing how I am hooking all this up together.

thanks

ljones


* setup.jpg (30.92 KB, 640x480 - viewed 747 times.)
« Last Edit: March 14, 2010, 06:42:13 AM by ljones » Logged

obarthelemy
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« Reply #1 on: March 14, 2010, 09:45:53 AM »

have you tried connecting your stick directly to the plug, instead of to the USB hub ?

We must try and find at least 1 very good quality USB hub. Everybody needs them, and most are creating lots of issues. Anyone ?
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birdman
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« Reply #2 on: March 14, 2010, 09:49:19 AM »

So does anyone here know of a good stable usb wireless device that will work with the sheeva without all the dropout and disconnects?
Well - as noted in the thread you mention, I have one of these which seems to work OK for me (I run it from a hub which only gets powered if I'm about to add a USB disk drive to it).  It has had the occasional dropout, but only very infrequently, as far as I can tell.   It has the advantage that you can change the aerial to improve the signal (and, in my case, end up with the aerial a few feet away form the plug).
It runs warm, but I think most of them do.
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ljones
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« Reply #3 on: March 14, 2010, 04:28:22 PM »

Yep, I've tried running the wireless USB device straight off the sheevaplug, but it dosen't make any difference. It still drops out and misses pings like there's no tomorrow.

The link to the 400mW USB wireless device looks intresting,  though a pity (so far as I can tell right now) it isn't sold in the UK.

Is it me or are a lot of people having issues with USB wireless devices and the sheevaplug? It would point back to either a software or hardware failure on the sheevaplug.....maybe its USB controller isn't too great?

ljones
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birdman
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« Reply #4 on: March 15, 2010, 06:00:42 PM »

The link to the 400mW USB wireless device looks intresting,  though a pity (so far as I can tell right now) it isn't sold in the UK.
I am in the UK!  When I ordered it it arrived in a few days and was posted from somewhere in Kent.
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birdman
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« Reply #5 on: March 18, 2010, 06:16:46 PM »

Hmm...just noticed a few things about my Wifi connexion.
At 2.6.33 it only runs at 20dBm power (100mW) and this can't be adjusted, as "iwconfig wlan0 txpower xx" reports an error (the ioctl call fails).  Looks like something recently broken in the rtl8187 driver?

I'm also seeing the connect speed drop noticeably at times.  Whereas I use to be able to transfer files (before recent power supply problems) at 1.3MB/s it now often drops to 40kB/s.
But it does seem that I get back to 1.3MB.s (or even 1.7+) if I power up the hub that the Wifi USB stick is on.

You might wish to try supplying external power for you current Wifi USB stick to see whether it helps at all.

Edit:  Ahh - just reviewed your drawing - you already have a powered hub....
« Last Edit: March 18, 2010, 06:18:17 PM by birdman » Logged

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