Pressure transducer (sensor) for OpenSprinklerPi

[Robert]

Yea, I know the software support isn’t necessarily there, but skipping all of that, is anyone aware of an inexpensive pressure transducer or sensor of some sort I could hook up to a Pi that is also hopefully fairly easy to install in your typical irrigation setup (like built into something with 3/4 inch threaded connections or something similar)? It’s secondary water, so it’s not going to be very clean and I’m also hoping to not have to deal with a filter that needs regular cleaning.

The problem is that the city provides a pressurized secondary water service and it’s undersized for my neighborhood when things get hot. It’s not unusual for my irrigation to fire up and I discover my impact sprinklers just aren’t working right due to too many other people irrigating at that moment. A little while later, things are probably fine. I’d like to be able to sense water pressure before firing up each zone and if the water pressure looks low, just wait until it looks good for some small period of time (5 minutes) before launching. Now I realize that pressure may drop mid cycle on me, but this way at least I figure I’ve got a fighting chance. As it stands now, my yard looks pretty dead and I’m tired of the Russian roulette going on. I need to build some “brains” into the system to fight the problem. I can probably even opt to run my less demanding zones during time when pressure is low.

My only other options are probably either to live with it, or hook a pump up to the system. I tried complaining to the city last year and didn’t get very far with that.

Thanks!

[Ray]

Wouldn’t it be easier to install some sort of adapter to increase the water pressure before feeding it to the sprinkler valves? This would be much easier than to install a pressure sensor and then modifying the software to implement what you have described.

[Robert]

The only way I’m aware of to pull that off would be a pump – and a pump isn’t cheap, would require more than a trivial amount of electric in a spot I’d rather not run it to (short of some major plumbing to run it back to house from the street, then back to the street from the house), and probably require a decent amount of maintenance. I was hoping (probably falsely) for something fairly cheap here. I priced some flow sensors (another approach) though, and if they’re any gauge, there probably isn’t a cheap way to do this. Now if you’ve got some trick I’m not aware of, please enlighten me – I’d love to discover there really is a cheap/easy way to deal with this.

[Ray]

I am not expert on this: but I thought there is something called water pressure regulator that allows you to adjust water pressure. I assume you can either increase water pressure or lower water pressure.

[Robert]

I’m not an expert either, but the pressure regulators I’ve seen are for making sure that the pressure doesn’t exceed X amount and reducing it if it does. If you want to increase pressure (my problem), you need a pump. Most people have a pressure regulator in their home (typically required by code) to make sure if you suddenly see a pressure surge from the water company it doesn’t blow up the plumbing and appliances in your house. Some of us (like myself) really wish it could increase water pressure so I wouldn’t have to whine to the city about my lackluster culinary water pressure (I have issues with both culinary and secondary(irrigation)).

Water pressure is essentially a form of potential energy given there are devices that can turn pressure into electrical energy – so it makes sense if you’re pressure is too low that you’ll need a device that turns electrical energy into mechanical energy (an electric pump) to get the pressure back up.

[Mike]

Pressure sensors can be had of course. Not sure what you have in mind when you state inexpensive, but you can find items at Digi-Key here: https://www.digikey.com/products/en?FV=ffec5663

Here’s an interesting one: https://www.digikey.com/products/en?vendor=0&keywords=NSCDANN150PGUNV

Another thought is a pressure tank. These are also commonly available and can probably be sourced locally. Several options here: https://www.homedepot.com/b/Plumbing-Pumps-Well-Pumps-Systems-Pressure-Tanks/N-5yc1vZbqld/Ntk-Extended/Ntt-water+pressure+tank?Ntx=mode+matchpartialmax&NCNI-5

Mike

[Author]

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