Category Archives: Hardware

Nest for Sprinklers: OpenSprinkler

My friend Jeff Cable was one of the early adopters of the Nest thermostat. At the time we talked a lot about the obvious next step of supporting home sprinkler/irrigation controls. Especially here in California (where we are in a pretty serious drought), having better control over irrigation (not to mention the remote access) seems like the logical next step.

Rather than waiting around for Nest, I just bought and installed an OpenSprinkler. OpenSprinkler started out as a hobby kit for makers and they still sell it a variety of ways, from kits to completed units. The software is open source as well.

There is also the possibility that if OpenSprinkler can get certified by the EPA WaterSense program, that rebates from water agencies could be possible (similar to low-flow toilets, energy-saving water heaters, etc.). Getting certified is still on the to-do list according to this OpenSprinkler update from Feb 2015.


Replacing my old Lawn Genie controller with the OpenSprinkler controller was really simple. All the cabling is compatible (assuming you have the standard 24 VAC controllers), so it’s just a matter of reconnecting everything to the OpenSprinkler. You’ll also need to connect to your home network with an Ethernet cable. (The OpenSprinkler itself does not have Wi-Fi.)

Here’s a comparison of the old Lawn Genie and the new OpenSprinkler:

Photo of Lawn Genie sprinkler controller
My original 20+ year old Lawn Genie controller
Photo of OpenSprinkler controller
My new OpenSprinkler installed


The more interesting part is the software which is easy to set up from a web browser. You can give your zones nice names like “front lawn” or “back roses” so you don’t have to remember zone numbers. Programming the schedule is pretty straightforward as well. If you attach a rain sensor, the OpenSprinkler can also operate in a smart weather mode where it decreases the amount of watering based on local rain or weather forecasts from Weather Underground.

Once you have the software configured, I recommend downloading one of the OpenSprinkler mobile apps so you can control everything from around the house (via Wi-Fi). For me this was one of the best use cases: while I’m out adjusting sprinklers I can remotely turn each zone on or off. (I know, the exciting life of a homeowner!)

With all of the above you’ll have mobile access, but only on your home wireless network. You can also configure your home network to allow access externally from anywhere (depending on your comfort level for setting this up and exposing to the internet in general). Now you can have remote access just like you can for your Nest thermostat :)

Screenshot of OpenSprinkler mobile app
The mobile app interface, including local weather

New Mac PowerBook

Don’t know if I’m really ready for a full-blown “switch“, but I recently bought from a friend at work his old PowerBook G4. (He joined practically every other Mac user I know in buying a new MacBook Pro, so I’m benefiting from his castoff.)

I’ve been a Mac users off an on, but have never owned a decent one like this. There is no shortage of Mac users at work, so I’m getting the scoop on the “must have” software applications. This weekend’s trip to Gnomedex will be a good test as I go Windows-free for several days (which, for some reason, reminds me of a Ted Ferguson skit).

Game Consoles Galore

When the Xbox 360 came out, I wanted one bad. For once, I thought, I’d be on the cutting edge rather than waiting. But, scarcity of supply and the outrageous premiums on eBay turned me off and I decided to wait and see what happens with the upcoming Sony and Nintendo systems in 2006 (2007?).

Steven Frank (of Panic fame), a pretty hard-core Mac guy, explains why he bought the 360 in a recent blog post. He too was watching the results from E3 this year to see the future of console game systems. His take on Sony was great:

By pretty much all accounts, Sony couldn’t have done worse if Ken Kutaragi had personally jumped over a shark tank on a motorcycle. Did they say SIX HUNDRED dollars? Oh, but hang on, it’s not just a console, it’s a media hub.

You know what, Sony? You are not a hard-hitting entertainment industry media powerhouse. You never have been, and no matter how many times you try to pretend that you are, you never will be. Take your Blu-Ray, your Memory Sticks, your DRMed rootkit-infected CDs, your “Universal” Media Discs that play in precisely ONE device, your MiniDiscs, your two PSP games that don’t suck, and shove them all up your LocationFree BetaMax.

Maybe I should just pull the trigger and get the 360 today (Father’s Day is coming up…). In the meantime I’ve overcrowded our entertainment center with second-hand PS/2 and the original XBOX systems (to go with the kids’ GameCube) — lots of games to try now, if we can just find the time :)

Delta Power?

While doing some research on APC uninterruptable power supplies, I was browsing their knowledge base when I discovered this surprising note:

Never use a domestic model APC UPS on a ship

In North America, one would expect to see approximately 120 volts when measuring from hot to neutral and from hot to ground. However, larger ships use delta power. That is, there are two hot legs (center tapped 120Vac) and a ground: no neutral. Each hot is 60 volts. One can measure from hot to hot (phase to phase) and will see 120 volts. When measuring from either hot to ground, one will see 60 volts.

It’s been a long time since I understood exactly how AC power works, but you can read the full article for the gory details. (Don’t forget to read up on the corollary as well: Never use Smart-UPS X93 Shipboard series with land power.)