Projects/Netlight

Project Netlight
Name	Netlight
Start	2012-07-27
End	2012-07-29
Contact	User:Pietdv
Website
Information	The network traffic light at haxogreen
Status	Production

Because of a faulty switch the network at haxogreen 2012 was quite buggy for a while. After a couple of hours we were sick of opening up a terminal and starting a ping to check if the internet was up. We had a raspi and a traffic light available, so we started hacking. We made a little relay board to let the raspi control the traffic light, and wrote a shell script to check if there was an internet connection and set the traffic light to green if there was, to red if there wasn't.

http://www.youtube.com/watch?v=uxdJv-h0Fks

People who helped

• Pietdv
• gmc
• Zarya

Gallery

• 
• 

  Raspberry PI with a relay board connected to it

• 

  The schematic of the relay board

Script

Note: The script was written to control the green and red light separately, But we designed the relay board so that it can be done with one pin — and one relay. The script still controls a seconds gpi pin, but we just don't use it.

#!/bin/sh

IP="8.8.8.8"
TIMEOUT="2"
GPIO_GREEN="23"
GPIO_RED="24"

# no user-servicable parts below

echo ${GPIO_GREEN} > /sys/class/gpio/export
echo "out" > /sys/class/gpio/gpio${GPIO_GREEN}/direction
echo ${GPIO_RED} > /sys/class/gpio/export
echo "out" > /sys/class/gpio/gpio${GPIO_RED}/direction

while [ 1 ]; do
  ping -c 1 -W 2 -qq ${IP} > /dev/null 2>&1

  ec=$?

  if [ ${ec} -eq 0 ]; then
    echo "1" > /sys/class/gpio/gpio${GPIO_GREEN}/value
    sleep 3
    echo "0" > /sys/class/gpio/gpio${GPIO_RED}/value
  else
    echo "0" > /sys/class/gpio/gpio${GPIO_GREEN}/value
    echo "1" > /sys/class/gpio/gpio${GPIO_RED}/value
  fi
done