At home, we have been connecting the garden, lights, doors, the TV, air conditioner, and even Higgs, our pet rabbit, but this last thing will be another post. We have a large variety of devices and sensors, with several Raspberry Pi 2 among them, connected to the WiFi network. Many times we have had to manually reboot the Raspis after a network connection outage because it looks like dhcpcd does not manage this situation.

After looking for a solution and finding some more or less complex solutions, my favorite one, for its simplicity, is this proposal by Alex Bain. So, I have adapted it to work with the distro I’m currently using, which is Raspbian Buster.

You will only need to create a script named /usr/local/bin/wifi_rebooter.sh, with a similar code to the one below, you may need to change the ping address and the interface name, which is typically called wlan0:

#!/bin/bash

# The IP for the server you wish to ping (192.168.1.1 is typically your router)
SERVER=192.168.1.1

# Only send two pings, sending output to /dev/null
ping -c2 ${SERVER} > /dev/null

# If the return code from ping ($?) is not 0 (meaning there was an error)
if [ $? != 0 ]
then
    printf '#' >> /tmp/wirelesscount
    ln=$(stat --printf="%s" /tmp/wirelesscount)
    if [ $ln -gt 2 ]
    then
        # third time reboot raspi if everything else fails
        cat /dev/null > /tmp/wirelesscount
        reboot now
    fi
    # Restart the wireless interface
    ip link set wlan0 down
    ip link set wlan0 up
else
    # reset count if it worked
    cat /dev/null > /tmp/wirelesscount
fi

Then you give the script run permission:

sudo chmod +x /usr/local/bin/wifi_rebooter.sh

And you add a 5 minutes interval to run it in /etc/crontab, so it will restart the network interface whenever the connection is lost:

*/5 *   * * *   root    /usr/local/bin/wifi_rebooter.sh

Now I no longer need to manually restart all our Raspberry Pi devices every time the connection has been broken for some time.

Makers gonna make.

• IoT
• Raspberry Pi
• Raspbian
• Tips & Tricks