How to add motion sensor to Rainbird irrigation systems?

Discussion in 'Irrigation / Sprinkler Forum' started by rancho, May 20, 2020.

  1. rancho

    rancho New Member

    Joined:
    Jun 3, 2018
    Location:
    California
    Some of you may have heard of the battery operated Contech Scarecrow and Orbit Yard Defender motion sensor sprinklers you attach to a garden hose to deter pests such as stray cats, deer etc..

    Instead of having a garden hose laying out 24/7, I would like to rig up my existing in-ground lawn irrigation to fire off from motion detection and then turn off again after less than a minute or even less than 10 seconds if possible.

    What would required to rig this up? I want to be able to rig it up so I can set exclusion dates and times for when the lawn is going to be mowed or other activities near the lawn are scheduled.

    Here are some photos of the existing Irritrol set up.
     

    Attached Files:

  2. wwhitney

    wwhitney Active Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
    Some general guidance, I don't know anything about specific products:

    That Irritrol is 24VAC powered (per the manual, worth it to double check the power supply). So it would be simplest if everything you add is also 24VAC powered. Then depending on the load of those components, and if you want to trigger more than one zone, you may need to get a bigger 24VAC power supply.

    You will need 3 logical devices (probably simplest to find as separate physical devices) :

    A motion sensor
    A countdown timer
    A calendar timer (or you could use a manual switch)

    The motion sensor feeds the input of the countdown timer. The countdown timer is in series with the calendar timer, and that series pair is in parallel with the Irritrol timer for the zone(s) you want to activate.

    If your zone(s) takes some time to fill before water starts coming out, that would obviously affect how long you set the countdown timer to run when triggered.

    Hope this helps.

    Cheers, Wayne
     
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  4. rancho

    rancho New Member

    Joined:
    Jun 3, 2018
    Location:
    California
    Would it be better/easier to somehow bypass the Irritrol and connect the motion sensor and calendar timer directly to the existing valve (or install a new additional valve)?
     
  5. wwhitney

    wwhitney Active Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
    You will effectively be doing that (versus somehow signaling to the Irritrol that it should trigger its relay to activate the valve). I don't see any benefit to the extra valve.

    If you want to use separate power sources for the Irritrol and the other equipment, then you can use a relay that the other equipment triggers to provide power from the Irritrol power supply to the valve(s) you want to trigger.

    Cheers, Wayne
     
  6. rancho

    rancho New Member

    Joined:
    Jun 3, 2018
    Location:
    California
    Do you have any suggestions on what would work as the countdown timer and calendar timer that be attached to this irrigation setup and where to buy those devices?
     
  7. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    Rancho, are you using a well pump or city water? If city water it is very easy. Install a second valve in parallel with the one zone you want to activate. If the Contech can put out at least 18 volts dc using batteries, connect the wires to the solenoid of the added valve. But it won't have that voltage and you would need to build a box with a lot of batteries and relays.

    If you can run another wire from the controller to get 24v ac, building a box with a contactor that operates from the Contech device will also work. You can buy a motor start relay in a box and accomplish what you want to do. You'll need to open up the Contech device to get to the leads to wire in a micro switch to Activate the contactor. Depending on the number of batteries the Scarecrow uses, determines the micro switch relay to buy. If you want to operate at night only, you'll need to incorporate a photo cell.

    I saw that device on Facebook, pretty neat. I'm doing this from an iPad so not easy to draw it out. Just don't touch the controller, it cannot do what you want exactly.
     
  8. rancho

    rancho New Member

    Joined:
    Jun 3, 2018
    Location:
    California
    It’s city water and I need it to work both day and night, but I also need it to have a timer that’s sophisticated enough to have days of the week instead of just hours. I need to be able to automatically exclude the mornings of days the lawn will be mowed, but still work the rest of the day and night even on those days.

    The Irritrol box is on a different side of the house than the motion sensor needs to face. So, I’d rather not need to have wiring running that far.
    I’d rather just have a dedicated new outdoor-use rated motion detector (like used for security alarms and lighting) than mess with trying to modify the battery operated Contech device.
    If 24v AC motion sensors don’t exist, could I just use a regular outdoor motion sensor and connect it to some kind of transformer converter?
     
  9. AlanMcLean

    AlanMcLean New Member

    Joined:
    Jul 17, 2020
    Location:
    Vancouver, BC
    We also installed a good pump for water supply and irrigation system that responds to movement with sensors. But I can't say that it helped against the animals. Our dog played with it constantly and jumped on the beds trampling the crop. To tell the truth, about the insect control problem, it bothers me much more. Unfortunately, this year we had an invasion of pests and they settled right in the house. Indeed, I read a lot of methods on how to fight with them but nothing helped. So, the only bed bug infestation info that I understood was that we will not drive them out on on our own.
     
    Last edited: Jul 22, 2020
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