Looking for latch solenoid

I’d like to use a Rachio zone to release a shelf of hay for my horse. I’m looking for a 24vac solenoid but all I can find are 24vdc. Any pointers? If this works I’ll build more shelves and will need a bunch of Rachio controllers.

I did test this: https://www.amazon.com/gp/product/B01K69S1HI/ 24vdc - But with a minimum 1 minute scheduled time on a zone, the solenoid buzzes and warms up which is not great with possible programming errors and hay dust especially with a solenoid not rated for 24vac.

@billbrietstout - @Gene found this bank of 4 relays for another purpose.


They do not latch open, but maintain the switched state for the duration of the zone run. There are plenty of 24 VAC relays on Amazon, not sure why they didn’t show up.

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You can convert AC voltage to DC voltage using a rectifier. I recommend something like this (link) pack of 3 from Amazon.

Simply connect Rachio side to the input and the electromagnet lock you’ve found to the output. Everything should than work.

Edit: now that I’ve looked at your lock closer, I see a possible issue. The rated current of the lock is 1 amp, which may cause an issue with Rachio’s short circuit protection. It is possible that the rating is overestimated to make the lock appear more powerful, but it is possible that the solution may end up being to use the relay @DLane has linked to in conjunction with a separate DC supply.

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Thank you DLane, Gene, you guys are the best. Your responses help keep me on the right path.

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@billbrietstout - thanks! @Gene is the electrical genius, I’m just a FTSO guy.

I don’t know the interval between someone checking on the horse(s) but one may want to consider a way to validate that the hay dropped. Rachio doesn’t know what it doesn’t know. For instance, if a rat (I’m sure plenty around a barn) chewed through the common wire before any of the solenoids Rachio would think that it triggered the zone but no current can go through the latch.

A camera that sees the hay station would work (e.g. Nest, Ring, etc.) or some sort of a contact when the shelf is closed or open that could signal something - back in the day Wemo Maker would work, but they don’t make that device anymore.

Just wouldn’t want your horse(s) to go without food for a long period of time.

Thank you, I got that covered. Four of the controllers you suggested are arriving today (Thursday).


Sorry, I didn’t see this earlier, but figured I’d give the direct answer. There are 24VAC relays. A common cheaper but still good brand is IDEC, part number RH1B-ULAC24V for $10. SPDT, but you can get in DPDT also depending on needs.

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Fab relays are 24 volts ac. I used them to interface my old 110 volt water solenoids and pump relay to the rachio.

50s Technology

Look at the size of those solenoids next to the newer one.