10 minute project: Traffic counter for router

I’ve been joking about making a new case for my wireless router for a long time. The idea was that that would be shaped like a McDonalds store, with a little sign out front that says how many billion bytes (or whatever) have been served. Tonight, I decided to see how hard it would be to cobble together the technical portion of the project using an Asus WL-520 router running MightyOhm’s OpenWRT build and an old display that I had sitting around.

Using my python library as a reference for how to use the display, and my XML parsing script for ash, I was able to cobble together a working project quickly. My source code is after the break.

Now, to complete the vision, I just need to make some golden arches…

screen.sh is the script that figures out the amount of information transmitted by the network interface, and the second file is an example cron job to make an update every minute.

cat /root/screen.sh

#!/bin/ash

TTY_DEV=/dev/tts/0
NETWORK_DEVICE=wl0

# Configure the serial port
stty -F ${TTY_DEV} 9600 cs8

# Turn on the led backlight
echo -e "\x14\xff" > ${TTY_DEV}

INFO=`ifconfig ${NETWORK_DEVICE}`
TMP=${INFO#*TX\ bytes:}
TX_BYTES=${TMP%\ (*}

TX_MBYTES=$(($TX_BYTES/1000000))

echo -en "\x0C" > ${TTY_DEV}
echo -n "McRouter        " > ${TTY_DEV}
echo -n "Served " ${TX_MBYTES} "MB" > ${TTY_DEV}

cat /etc/crontabs/root

* * * * * /root/screen.sh