Linux Reef Controller – NSLU2 Sensor Server


The Linksys NSLU2 Network Storage Link device can easily be hacked with a modified firmware and used as a sensor server for your LRC. Here’s how!

  • First you gotta find one! Since they are not manufactured anymore this can be tough or expensive!
  • Download the latest Unslung firmware from here.
  • Follow the firmware flashing instructions provided in the Unslung Firmware README
    • Make sure to follow the instructions TO THE LETTER!!

  • After you have sucessfully flashed your NSLU2, ssh into it and perfrom the following commands to update it:
    • ipkg update
    • ipkg upgrade
    • DO_Reboot

  • After the device reboots install some necessary packages
    • ipkg install openssh nano usbutils ntpclient
    • Follow the guide here to fix an issue with the hardware clock and ntpclient
    • DO_Reboot

  • Setup OWFS
    • nano -w /etc/ipkg/owfs-feed.conf
    • Add the following to the owfs-feed.conf file:
    • src/gz owfs
    • Save the file and run the following commands:
      • ipkg update
      • ipkg install owfs owshell
      • run-owfs
    • You should be able to access the owfs server from the built in web interface.
      • http://DEVICEIP:3001/
    • DO_Reboot

  • Your Linksys NSLU2 is now ready to serve as a OWFS sensor server
  • Get yourself one of these and some sensors, plug them in and reboot the NSLU2 for the correct modules to load on boot.
  • Once the device is rebooted you should be able to see the sensor Id’s listed in the web interface.
  • You can also view all of the devices by using the following owfs commands in an ssh session
    • List the one wire directory tree:
    • List a sensor directory:
      owdir /SENSORID
    • Read sensor data:
      owread /SENSORID/variable
      • A temperature sensor read example in Farenheit
      • owread -F /28.2F2840020000/temperature

  • Your Slug is now ready to be polled by the webserver via cron jobs and perl scripts!