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Quick Links: Part 1, Part 2, Part 3, Part 4, Part 5

Hardware

As mentioned in Part 1, Insteon was chosen as the platform of choice for building the irrigation controller.  All of the various pieces and parts that were required were available in Insteon-capable devices.

One of the key benefits of going with Insteon was the availability of a relatively low-cost stand-alone controller (the Universal Devices ISY-99i) that would allow the irrigation system to be controlled without requiring a PC to be running.

Most of the components that were required to build the controller can be re-used for other home automation projects which made more sense economically than purchasing a dedicated irrigation device that could only be used for irrigation control.

Required Hardware

The hardware buy list was as follows:

1. SimpleHomeNet EZFlora 8-Zone Sprinkler Controller
2. 24V AC Power Supply w/Auto-Resetting Fuse
3. SmartHome PowerLinc Modem – Serial (2412S)
4. Access Point Insteon Wireless Phase Coupler 2 Pack (2443P)
5. Universal Devices ISY-99i
6. Miscellaneous pieces and parts for the wiring inside of the ‘irrigation control box” (details below).

Hardware Installation

This section will focus on the installation of the irrigation controller equipment and will only briefly cover the installation of the other Insteon components.  Other folks like P. Lotus have done an excellent job describing the Insteon installation process so I’m not going to repeat that here.

When I was researching the EzFlora (previously known as the EzRain) I wasn’t able find many installation and configuration resources so hopefully this will be helpful to you if you are considering going down the EzFlora and ISY route for irrigation control.

Irrigation Control Box

Our existing irrigation controller was mounted outdoors and was built into its own weather-proof box.  The metal box was lockable and it made for a perfect housing for the new irrigation hardware.

It didn’t take long to remove the guts of the old controller.

I labelled the wires for each of the zones to speed up the wiring process for the EzFlora.

The box had sufficient room to fit the power supply and the EzFlora mounted side-by-side.  I used two small electrical boxes bridged together with a gap to accomodate the width of the power supply and the EzFlora.  The power supply and the EzFlora will not fit side-by-side in a two-gang electrical box.

Because the Insteon devices communcate over the powerline, there was no need to run any additional wiring to the box which kept the installation simple.

I intentionally left room for a third electrical box in case I eventually wanted to install manual controls (using an Insteon KeypadLinc).

The power supply and the EzFlora installed inside the box.

I added new weather stripping to create a weather-proof seal.

Wiring Up the EzFlora

The EzFlora is powered via the electrical outlet and the irrigation valves are powered by the 24V AC power supply.  The output from the power supply is connected to the “AC Xmr” connections on the EzFlora terminal block (polarity doesn’t matter).

The wiring of the irrigation valves is straight-forward with each zone being connected to the appropriately labeled zone numbers on the EzFlora terminal block.  The common lines for the valves are connected to the “Comm.” terminals.  I had two common lines, one running from each in-ground valve box so I just connected these to the two individual “Comm.” terminals.

Note: The set screws are pretty small so you’ll need a precision flat-head screwdriver.

Here is a picture of the final EzFlora wiring.

A Note About Testing the EzFlora

Prior to completing the installation in the controller box I tested the ability to control the EzFlora from the ISY.  I expected a 24v AC load to be present between the specific zone terminal and the common when the zone was set to ‘on’ but I was unable to get a 24v AC reading from a multimeter.

I discovered that the switching mechanism is more than just a simple relay and it only works when a load is applied.  I connected an extra valve solenoid that I had lying around and I was able to test all of the zones successfully before installing the hardware in the controller box.

Installation of the Remaining Insteon Devices

The installation of the remaining devices is pretty self explanatory and decent instructions are provided.  Here are some gotcha and general notes about the remainder of the hardware installation.

Access Points

When installing the Access Points I discovered that the two electrical phases in our home were able to transmit the Insteon signals quite well so I never got a ‘solid bright light’ when installing the second Access Point.  After a quick call to SmartHome, they informed me that this was fairly common.  I was able to install the devices on different phases by flipping breakers (typically each vertically sequential breaker in the box is on the opposite phase).

PowerLinc Serial Modem (PLM)

I installed the modem in a free outlet near the computer but on a different circuit than the circuit that powers my UPS (to which all of my computer equpment is connected).  I ran a couple of quick tests directly from the computer serial port using the BusyRat PLM Test Tool.

I discovered that the SimpleHomeNet EzFlora configuration software doesn’t work with the PLM (a PLC is required).  This was not a big deal as the ISY doesn’t support internal EzFlora programs anyway and I had no need for these capabilities in my final setup.

ISY-99i

I went with a refurbished version of the ISY-99i to save some cash and the device that I received was in perfect condition.  The ISY is conveniently powered from the PLM so no additional power supply is required.

You can optionally add a 5V DC power adaptor which I will probably do later so that I can connect the ISY to my UPS.  The PLM cannot be plugged in to a UPS as the UPS will filter the powerline Insteon signals.

The ISY-99i is very compact and I installed it  next to my networking equipment.  The short ethernet cable provided was ideal for connecting to the router but I had to substitute a longer ethernet cable to connect the ISY to the PLM.

My Linksys router is a WRT54GL running DD-WRT.  DD-WRT has the ability to create statically assigned DCHP addresses (associated by MAC address) but I still had some trouble with the ISY’s internet connectivity so I ended up setting the ISY’s ip address statically (using the telnet interface).

That’s it in terms of hardware.  A pretty simple set up and it this point I was able to turn sprinkler zones on and off using the ISY web interface.

Next up, setting up the software.

Continued (Read Part 3)

Quick Links: Part 1, Part 2, Part 3, Part 4, Part 5

In either case, it really wasn’t a very smart controller as it did nothing but respond to a fixed watering schedule that was set by inserting thumb-screws and rotating dials.

While it served its basic purpose, it was inconvenient to adjust the irrigation schedule resulting in wasted water in cooler months and insufficient watering in warmer months. It also didn’t support soak cycles, a technique to reduce runoff particularly with soils that have high clay content like we have in our neighborhood.

I had been intending to upgrade the controller for some time and a recent malfunction while we were out of town helped to finalize that decision (36 hours of water down the drain and a hefty water bill later).

Requirements

I wanted an irrigation controller that could respond to environmental conditions to control the amount of water being applied (something more intelligent than an on/off rain sensor).  With some quick research on available products I found that there are several different approaches to the problem:

1. Use local environmental sensors to evaluate watering needs (ex. rain sensors, soil moisture sensors etc.)
2. Use an on-site weather station to estimate watering requirements
3. Use off-site (local) weather information to estimate watering requirements

Of the approaches above the last option was the most appealing and I didn’t like the idea of having to maintain on-site sensing equipment or a weather station.

Smart Controller Options

The controllers that use off-site weather data use either forecasting or current weather conditions (or some combination of the two). Weather information is generally accessed via the internet or, in some cases, via wireless signals.

Forecast-based controllers adjust watering based on what is expected to occur while weather-based controllers use recent weather information to adjust watering schedules.

The systems that use current weather conditions are generally the most sophisticated and are known as evapotranspiration (ET) controllers.

The idea behind ET controllers is that local weather conditions are used to calculate the water-loss that occurs as a result of evaporation and transpiration from the lawn surface. By combining this with local rainfall amounts over the same period, the net water deficit can be calculated and used to control the amount of water that is applied by the irrigation controller.

This process seems simple enough but these tend to be somewhat pricey with internet-based controllers in the $500 – $900 price range.  In addition to the purchase price, most of the lower cost manufacturers charge annual subscription fees for access to local evapotranspiration information.

A Perfect DIY Project?

The internet-based ET controllers made a lot of sense to me and this looked like a perfect do-it-yourself project* with the following basic requirements:

1. The ability to control sprinkler zones from a computer (or ideally from an stand-alone controller so that a full-blown PC would not have to be running)
2. The ability to access local weather data over the internet to track rainfall and compute daily ET
3. The ability to program all of the above to build a customizable smart irrigation controller

* Why? Well why not? Sure, it would be easier to buy a ready-made ET controller but what’s the fun in that?

Platform

I had previously looked into home automation back in the X10 days but the relibaility was never purported to be that great.  A lot has changed since then and there are several new technologies in the home automation space.

After researching multiple hardware options I settled on using Insteon devices as the platform for this project.

The remaining posts in this series provide the details of the hardware and software solution that I used to create an internet-enabled smart irrigation controller.

Continued (Read Part 2)