How to fix unstable wi-fi connection

[kyuzumaki]

After setting up a pi as an ip camera I soon discovered my wi-fi connection was highly unstable often dropping out within a few hours occasionally after a day or two. After searching the forums and internet and a lot of messing around I have now got a stable wi-fi connection (uptime >2weeks now) I thought I would share my journey as it will hopefully help others with the same issue. I would probably advise trying option one and three first as they are less risky.

Index:

Issue 1 -> Power Supply
Issue 2 -> Usb Power
Issue 3 -> Wi-Fi power saving

Issue 1: Power Supply

Get a decent power supply from the start the one sold by the SWAG shop is reliable get it here
http://swag.raspberrypi.org/collections ... wer-supply

Issue 2: USB Power

Sadly this change alone did not fix my problem I constantly suffered brownouts and found that when I initiated high levels of wi-fi traffic the pi became totally unresponsive.

You can solve the problem with a powered usb hub however this did not suit me and the SWAG power supply already outputted a good 2Amps so I already had the power available...

After a lot of reading of schematics and other peoples attempts I decided to jump straight from the power supply to usb port. You just need two bits of insulated wire and some very careful soldering. Be careful not to overheat the components and to keep the exposed wire to a minimum as its easy to short across nearby contacts. I bridged the usb power connectors with solder to provide a better connection to the wire though it probably does not make a real difference.

This is what I have done and its worked fine, however I do not take any responsibility for damages caused to your pi in copying this method.

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I have been told the ground wire is theoretically doing nothing however on testing I noticed a voltage drop when disconnected of about 0.3 volts. My theory is that the ground trace is too long or thin and has a higher resistance than it should. This may be unique to my pi but please if you try this mod post your voltage readings before and after!

Issue 3: Wi-Fi power saving

With this mod I no longer got the brownouts when under load but after 12-24hrs wifi disconnected again. A bit of a search revealed that power saving mode was the issue, when enabled it can cause the wifi adapter to stop working and never reconnect.

To disable wi-fi power saving
open the config in your favourite editor (I will be using vim you can use nano)

Code: Select all

sudo vim /etc/network/interfaces

move the cursor down below "auto lo"
hit the O key to insert a new line below
add this text

Code: Select all

wireless-power off

press :w to save and :q to quit vim
reboot the pi and you should now have stable wi-fi

[klricks]

As already mentioned in your other thread:
http://www.raspberrypi.org/forums/viewt ... 65#p605065
The connection as you have it is bypassing the FUSE and protection diode circuitry.
Putting a wire from the fuse pad to the USB 5V pins is electrically equivalent to removing the fuse and shorting across the fuse pads with a wire.

Have you updated your RPi recently?
WIFI seems to be more stable now. In the past I went through the gyrations of trying to keep the WIFI stable by doing similar config modifications but nothing seemed to work. Now on my newer B+ I have had no WIFI dropout issues at all with no special config mods. Though I should go back to the B model any try again.

[kyuzumaki]

I had updated it probably about 3 weeks ago, unless theres been another update since then.

I also bought a model B+ recently and its wi-fi is stable with nothing extra

[pieuser]

i also have same problem regarding wifi , i write in the /etc/interface file wireless-power off but still eth0 or wlan0 not connected. any solution.