WiFi

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Compact Flash Wifi

NB: Recent gumstix buildroot revisions come with Compact flash enabled by default, instead of MMC.

To enable CF rather than MMC: edit the file /etc/modules and comment out or delete the MMC lines; then rename /etc/init.d/s30pcmcia to /etc/init.d/S30pcmcia and reboot.

To enable WiFi edit /etc/network/interfaces to have auto wlan0, and optionally any wifi settings you may wish to set.

Compatiable CF cards

Ambicom WL1100C-CF

Some of these cards work with the gumstix. The manufacturers changed the chipset without changing the product code, so finding working cards is a matter of luck and hoping you get an older card. We have tested 2 cards, one worked, and the other did not.

  • Working card serial number was: WL2232009702
  • Not working card serial number was: WL2513004045


Wifistix

Power Usage

If connecting to an Access Point with the wifistix it is possible to enable power management with the iwconfig utility, which will also help with temperature issues.

Craigs post on WiFistix power use:

> waysmall STUART + gumstix connex 200xm running at 100% CPU usage with
> wifi link established and radio at max. power output: 0.34A at 4V =  
> 1.36W
> CPU idle (+/-0% usage) but with wifi link up at full output power:  
> 0.29A
> at 4V = 1.16W
> CPU idle, radio Tx turned off via "iwpriv mwlan0 radiooff 1": 0.23A at
> 4V = 0.92W
> CPU idle, hold reset line high on the wifi module to completely  
> disable
> it: 0.13A at 4V = 0.52W

The wifistix does not support the `master' mode (i.e. acting as an Access Point). It is possible to implement some of the same functionality in Ad-Hoc mode, but there is no power management available, and the wifistix may get very hot due to the increased demands of Ad-hoc operation. Some devices will also not accept the gateway from dhcp on an Ad-hoc network.

Configuration

The relevent lines are needed in /etc/network/interfaces

A typical setup which will only look for ECS WLAN (and shows how to set power) is:

auto mwlan0
iface mwlan0 inet dhcp
        pre-up /sbin/iwconfig $IFACE essid ECS-WLAN txpower auto

Note the txpower option auto rather than say 100mW is to save power on the board (they get hot othewise!)

To run in Ad-hoc mode with a fixed IP address:

auto mwlan0
iface mwlan0 inet static
        address 192.168.1.1
        netmask 255.255.0.0
        pre-up /sbin/iwconfig $IFACE mode ad-hoc essid AladdinWeather

Type iwconfig mwlan0 to see the current setup. To stop/start the network use "ifdown mwlan0" or "ifup mwlan0"

Another useful power option is "iwconfig mwlan0 power on" which means power management on. You will see LED1 flickering once its online.