Ronny L. Bull

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!
• A good place to start looking would be here: Cisco-Linksys Storage Link for USB 2.0 Disk Drives NSLU2

• 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 http://owfs.sourceforge.net/nslu2/packages

• 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:

  owdir

• 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!