MBWE Fuel Gauge -> Speedometer conversion

The Fuel gauge on the front of my MBWE is fairly useless, noone cares, so why not repurpose it as a speedometer?

first, stop it displaying the "fuel" Stolen from http://kyyhkynen.net/stuff/mybook/reduce_disk_usage.php

Disable the service that displays the disk usage with the leds in the front panel of your MBWE. Admit it, the feature is pretty much useless and because the service has to check the amount of free space on the disk(s), it is causing disk access.

In order to prevent the service from starting during boot, edit /etc/init.d/S15wdc-fuel-gauge. Comment out this line:

$FGD &

Then stop the service:

# /etc/init.d/S15wdc-fuel-gauge stop

Once all thats done, this is my script (The ultimate in lazy)
#!/bin/bash
INITIAL_RX=`cat /sys/class/net/eth0/device/net:eth0/statistics/rx_bytes`
sleep 10
FINAL_RX=`cat /sys/class/net/eth0/device/net:eth0/statistics/rx_bytes`
DELTA_RX=`expr $FINAL_RX - $INITIAL_RX`
KBPS_RX=`expr $DELTA_RX / 10240 `

let "RESULT = $KBPS_RX / 3"
echo $RESULT > "/sys/devices/platform/wdc-leds/leds:wdc-leds:fuel-gauge/brightness" 
The 3 in there is the scaling factor between the kbps download and the number of lights on. 
Since I'm not often downloading any faster than about 400kbps, and when i am im not really worried about i

0 to 100: lights one led (5 o’clock)

100 to 150: lights two leds (5 and 7 o’clock)

150 to 200: lights three leds (5, 7 and 9 o’clock)

200 to 250: lights four leds (5, 7, 9 and 11 o’clock)

250 to 280ish: lights five leds (5, 7, 9, 11 and 1 o’clock)

280ish and more: lights all leds.


I have the whole thing running as a cronjob every 5 minutes, do that urself