How to use a magnetic flow switch with HE?

I would like to use this magnetic flow switch to monitor my irrigation system.

How can I remotely connect this to HE to be notified if water is flowing?

From the reviews looks like you'll need some electronics in between, like an arduino or possibly a raspberry pi. Not my area of expertise....

Yes, that is the part that is a little fuzzy. I was thinking that I need a z-wave, wifi or zigbee module that will respond to NO NC contact changes and notify me of any change.

It isn't quite that simple. This thing outputs a pulse train with a frequency proportional to the flow through it:

F=(5.5*Q)±2%, Q=L/Min, error: ±2%

That would be a LOT of on/off changes for your contact sensor to report.

You either need something that can measure the frequency of that pulse train directly and report it back (Pi or Arduino with a 5V digital input, plus some custom code) OR you might be able to take an analog measurement and do some empirical testing to figure out how to scale the measured voltage level to its corresponding flow rate.

Looks like a fun project, but it seems likely that it'll require some custom code and electronics.

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I'd use an ESP32. ESPHome may have a pre-built solution if you don't mind going with Wi-Fi.

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You could start with this...

I have seen other users of similar devices successfully use HubDuino’s Pulse Counter device to integrate these with Hubitat.


I'm not clear whether you are you looking for a Flow Meter (measured amount) or Flow Switch (On/Off). From your initial description, it sounds like you just want to know on/off; a switch is a fairly simple setup with probably a number of available solutions (but not really the one you link.) For example, I use a NO reed switch wired into a Qubino 1D Relay to monitor whether I am getting flow out of my pool pump when it is on.

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Yes, I don't need flow rate, just whether water is flowing or not.

So you could get a flow switch and connect the output to an input device like a door switch with screw lugs or something like a smart implant so that when there is flow, the contact will send a signal to HE.