Rain8 vs Elk-M1


Active Member
I've read a few threads about using the Rain8 products for controlling a sprinkler system. I also read an application note on the Elk web site about using the Elk - I assume via relays - to control a sprinkler system. I'm still not clear on why I would want to use the Rain8.

If the Rain8 device is the way to go, it seems that I could control a Rain8Net device via the Elk-M1 RS232. What does the Rain8 get me over what I can do with the Elk? I see that it has default max times for each zone, but I can just program times for the Elk relay to stay on.

I'm interested in how others have done this and what their experiences are. I want to make sure that I'm not missing something here.

The rain8Net devices have internal Max timers in case the control system dies. You won't have a flood when you get home in that event.

Here is the Rain8Net in action with MainLobby software running on a PC.
You can see visual state of each zone and the overall watering cycle on all networked PCs.

I use it to control my pond water features as well. Nice to use the MainLobby server automation logic to create effects.

Another nice thing of combining a security panel and the irrigation system is the ability to detect motion and shut off a zone temporarily when people are in the area. And, just the opposite, my driveway is about 1000 ft. winding thru the woods. At the end (begining) of the drive are plants that the deer love to munch on. I put a motion detector out there and turn on that zone's watering system when there is motion at night to scare away the deer from having a late snack.


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As DavidL mentioned above, if you are controlling the sprinkler system directly from a PC automation program, the Rain8 is a good choice.

With an M1 you could go either way: Control the Rain8 from a serial port or use a Relay Output Expander and write Rules to handle the valve control.

I handle the automatic water refill on a backyard fish pond with the M1 and M1RB relay board. I pay special attention to how long the water valve remains on with a cutoff override Rule. It has never overfilled the pond.

Note - Do Not Do This: One customer was writing Rules for his sprinkler system and wrote a Rule using THEN turn off value for X amount of time. This Rule turns off the output for a time delay and then turns it back on at the end of the time delay. The value turned off for the time period he included in the Rule and turned back on with no time delay just the way it was programmed to do. Result - Soggy yard! He quickly rewrote the Rule.
Cool, so the Rain8 is not a bad way to go since it gives me the flexibility of using either the M1 or a PC. Maybe I'll go that way so that I can tweak things down the road as I see fit.

I went throught the same delima and decided on using the M1 relay since it is not as complicated.

Spanky, is it possible to wire an override/bypass switch into the mix so that I could walk up to the M1XOVR and flip a switch next to it bypassing the M1XOVR 's relay causing the valve to run manually (from the same ELK M1 power source)?

edit: typos
There are at least two ways to bypass the Rules programming:

1. Wire a switch across the Output Relay contacts, effectively bypassing the relay. Make sure the switch can handle the current load of the valve.

2. Use switches to control inputs into the M1. Write Rules to turn on the relay outputs that controls the valves either from on/off switches or push switches. Push to turn on, push to turn off. You would use the toggle output function when writing this kind of Rule.

You might want to add a moisture or water sensor to an input on the M1 so not to water the grass after a rain.

For the time delay on the valves, use the Custom Settings Values when telling the outputs how long to water the grass on a zone. This makes it easy to change the watering time from the keypad or Touchscreen without having to rewrite Rules.
Another option (wheich I just posted in another thread) is to build a sprinkler controller board. It's less expensive, more flexible (you can design it and build it to control between 1 and 27 zones per board), etc, etc.

You can read more at www.rgbled.org -- scroll down to the Sprinkler Controller