Arduino compatible water pressure sensor/switch

Hey all, I'm looking for an Arduino compatible water pressure sensor or switch. I've literally searched on and off for months and can't find exactly what I'm looking for. I have a normal pump water pressure switch (40/60), and attempted to attach it to the Arduino, but failed. It would turn on perfectly when the pressure was at the low point, but would fail to stay on. I believe the pressure switch requires high voltage to maintain the contact until the pressure is sufficient.

The optimal solution would be a sensor that I could read from the Arduino to get the exact current pressure of my household water (range: 0-100 psi). However, if that's too expensive, an alternative solution would be two pressure switches to indicate low/high pressure states.

The end goal is to replace my well pump pressure switch with an Arduino. I'd also log the on/off events as a bonus.

Thanks in advance!

Sensors and switches work in different ways. You need to understand what your device is actually going to do.

Is it trying to give you an analog reading, proportional in some way to the pressure ? Is it trying to give you an on/off value, switching state at some arbitrary threshold pressure ? Is it going to give you a voltage, or an open/closed contact ?

What is it's expected operating voltage ? 5 V, ? 12 V ? 24 V ? 110 V ?

Any of those scenarios can be made to work with the arduino, but you need to know which scenario it is.

Thanks michinyon, totally makes sense. I'm hoping to find a decently priced sensor to give the Arduino an analog reading, proportional to pressure on the line. Do you know of any such device?

If that particular device doesn't exist, then I'm hoping to find a device which will simply provide an open/closed contact at a configurable pressure.


It doesn't seem like this should be very hard... I imagine a simple rheostat type of variable resistance, spring loaded to compress when water pressure rises. There's gotta be something... right?

Have a look here:

Sweet! Thanks! I've added this to my future purchase list:

Being that is $80+, are there any other options? I found a few pressure switches from that same link, but they were all 25-40, so not much more cost effective when buying two.

Thanks again!

I have one of these but haven't tested it with Arduino yet

Water/oil pressure sensors are most common & cheapest in automobiles. Ebay & amazon has a 2 piece digital pressure readout & pressure sensor for under $20USD for both, measures up to 120psi. Some sensors are 4 wire, battery &gnd. + 2 for meter (0-5V) or 4-20ma .

My home water pressure fluctuates all over the range from a near trickle to a blasting force. Most other industrial sensors were well over $50 and didn't exceed 20 psi but were very accurate, far beyond our needs.

This is where I am focusing my efforts. I will need an adapter from engine size connection to plumbing size at a hose faucet. I don't think this will throw readings off. Let you know results