PC Based Sprinkler Timer


Replacing the old sprinkler timer was one of the first home automation projects that I embarked upon.  The first iteration was a tiny DOS machine originally built as a Point of Sale device.  The fact that it was made to sit in the cabinet under the check stand conveyor belt was ideal for use in a hot garage.

The sprinkler system is controlled using a parallel port relay board.  DOS was fine for scheduled on/off for the most part but would not handle manual events.  A later Linux reload of the machine helped but had again had some issues.

I used a thin client machine that I purchased as a demo for a terminal server application in my office.  After the demo, I was stuck with a Neoware thin client.  It turns out this is an actual workstation machine with the boot ROM.  Remove the boot ROM and install compact flash (IDE) drive and it was whatever I wanted it to be.

The OS is Windows 2000 with some tweaks to thin it down quite a bit using NTlite.  In order to keep the IO to the compact flash drive to a minimum the virtual memory file reloaded to a RAMdisk.  A program called “EZsprinkle” that starts with the local user handles the scheduled watering of the yard.

Now using VNC to remote to the desktop, I am able to manually engage the sprinklers.  Nothing says “stay out of my front yard” like a blast from the sprinklers!

This machine has evolved over the years, nowadays you can buy a stick PC or a Raspberry PI that can do everything using a USB relay board or PI daughter board.  I hope this post has inspired you to look at junk as a blank canvas.  Even if there is little to no monetary value, you can still make it do something useful for you.  Enjoy!