How to Build a DIY Water Level Indicator?

Water level indicator can be of various complexity levels of different cost. A water level indicator is very much helpful at least in North America and India. Peoples in both of these countries outside the major cities need to pump a natural source of water into a reservoir and then pump to the overhead tank. The Source of natural water can be rainwater, a borewell or a tubewell. This kind of setup often needs some kind of DIY meter for level monitoring. Surprisingly it is neither difficult nor costly to build a basic DIY water level indicator.

Based on electrical conductivity

Simple electrical

The water of a tank conducts water nicely when the applied DC voltage is 5V to 12V. You can test it easily with a 9V battery, copper wire, a potentiometer and a LED. When water is present touching the tip of the problem it will light up. This is the basic of the most simple and cheap form of DIY water level indicator. Instead of a potentiometer, we will use a 470 Ohm resistor for a basic water level indicator. The working form of this circuit is quite simple. We will use multiple probes at various levels, keeping the (-) pole (or GND) at the bottom of the tank. When the water reaches the desired level the probes will be connected and the water will touch them.

With IC

We will not go into the details of the circuit. The most simple design of such a circuit is by using a ULN2003 Integrated Circuit (IC), 3 LEDs, and 1 buzzer. A complex form using a 74HC147 IC, a CD4511 IC and a 7 segment LED display. By using a ULN 2003 IC and relay, an automatic pump control system with LED level indicators can be made.

With Arduino

The total system described above can be replicated on Arduino. In this case, you have to convert the probe to a “sensor”, like described in this how-to guide :

The above project is enough great, yet we can add various features like a display, a buzzer, with ESP32 we can make it a “smart thing”. However, our basic principle remaining the same. The above two ways do not cost a ton to build a basic water level meter. But they suck a lot of battery, the copper probes get corroded etc. Both the problems can be fixed. Stainless steel probes (China made) are readily available for this purpose. The meter can be switched off when none is watching the meter.

How to add a sensor for “dry run”? Add a probe to the pump suction port tank.

Using an Ultrasonic Ranging Module

HR SRO4 is a commonly used, cheap ultrasonic ranging module. There is a waterproof ultrasonic module. While these modules are cheap, they may not deliver a great result in everyone’s setup. There are costly, professional-grade sensors with a whopping price tag of $150 to $200 which are technically superior. Peoples have researched about them :

Using a Laser Ranging Module

VL53L0X longer module costs around $10 and as it follows a straight line, it is often easy to run the thing. You need to use the Pololu’s library:

Water will damage a VL53L0X sensor as a precaution.

Conclusion

As we can clearly understand the budget philosophy – stainless steel probes are more than sufficient for day to day usage. Whether you’ll use an IC or microcontroller, that completely depends on your budget. The problem is finding a good quality stainless steel probe with thick, long copper wire.