Wireless Water Level Sensor From PVC Pipe

[Bob] was having trouble keeping up with his water troughs. He had to constantly check them to make sure they weren’t empty, and he always found that the water level was lower than he thought. He decided it was time to build his own solution to this problem. What he ended up with was a water level sensor made from PVC pipe and a few other components.

The physical assembly is pretty simple. The whole structure is made from 1/2″ PVC pipe and fittings and is broken into four nearly identical sensor modules. The sensors have an electrode on either side. The electrodes are made from PVC end caps, sanded down flat at the tip. A hole is then drilled through the cap to accommodate a small machine screw. The screw threads are coated in joint compound before the screw is driven into the hole, creating its own threads. These caps are placed onto small sections of PVC pipe, which in turn connect to a four-way PVC cross connector. 

On the inside of the electrode cap, two washers are placed onto the screw. A stranded wire is placed between the washers and then clamped in place with a nut. All of the modules are connected together with a few inches of pipe. [Bob] measured this out so it would fit appropriately into his trough, but the measurements can easily be altered to fit just about any size container. The wires all route up through the pipe. The PVC pipe is cemented together to keep the water out. The joint compound prevents any leaks at the electrodes.

A piece of CAT 5 cable connects the electrodes to the electronics inside of the waterproof controller box. The electronics are simple. It’s just a simple piece of perfboard with an XBee and a few transistors. The XBee can detect the water level by testing for a closed circuit between the two electrodes of any sensor module. The water acts as a sort of switch that closes the circuit. When the water gets too low, the circuit opens and [Bob] knows that the water level has lowered. The XBee is connected to a directional 2.4GHz antenna to ensure the signal reaches the laptop several acres away.

24 thoughts on “Wireless Water Level Sensor From PVC Pipe

  1. Farmers know how to hack and keep it simple. Toilet float or the TSC float switch.
    No “duino needed. The work is done for you.
    The first example of this was wind powered!
    If no water, start digging. Otherwise water forever.

    1. Reminds me of my granddads setup back in the 80ies. A natural spring would flow into a tank which would, once a week, be pumped into the main tank at the top of the hill. A bucket with a brick in it, a few meters of string and a wooden block painted red served as a level indicator. You could see it from the house about 300 meters away.

        1. Ignoring voltage drop from the transistor, wire and loss to water he’s pushing a max of 90 uA through the lowest sensor pair. It’s gonna take forever to corrode the bolts no matter what they’re made of.

  2. Nice example of using a laser ray gun to kill a cockroach :-D
    Our ponies had dis-examined that setup within minutes, finding out if “cementing the pipe” really keeps the water out, after you got the cement out of the pipe.
    I do agree on the question about corrosion – and even come up with a second elephant in the room: In the winter a frozen water coat around each of the junctions will tell the “hi tech lap top” that everything is fine, while the water in the trough is already at 0. Waterlevel, not temperature.

  3. The issue with floats and auto refill is when they somehow end up jammed on and just start flooding the trough. Couple that with not checking it for a week and limited water supply and you have issues…

    Which is why i imagine he probably likes manually filling them rather than the multitude of off the shelf auto fillers.

  4. I think you could argue that this is pretty severe overkill (and a natural curious horse chew-toy), but as an accessible entry-point tutorial/reference for XBee remote sensing, you could do a lot worse than the two videos.

  5. Putting a voltage, regardless of how limited the current is, through a watering trough seems rather fool-hearted. As an electrician I’ve spent countless hours removing trace voltage potentials from troughs to earth. Cows can easiy feel under 3V and will stop drinking water if their sensitive noses get shocked- not sure about other animals.
    As an apprentice I burned myself on an waterer heater element once and through that scar I was able to feel 2v by sticking it in the water and then another finger in the dirt- that was super handy for knowing if we eliminated the issue or not.
    Is my thinking wrong here? Is the fact that it’s a dc source from a battery make the system closed loop as the current won’t try to find path to ground through the animals nose?

    1. If the electricity becomes an issue, it obviously makes sense to try something else. For not only would a horse be poking its head in, you also could have small children who could be severely injured. Some of the alternative options would be a float based system (like one you would find in a toilet). The problem is that this system has moving parts that can fail, as was mentioned in prior comments. You also have a capacitively based option. An example can be seen from this Water Level Sensor. It has no moving parts, and is completely insulated, so electricity probably wouldn’t be an issue. Another option would be a sensor based resistively, although I’m not sure how well that would work in this particular circumstance.

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