Water level sensor: classification, purpose, description of the device

The water level sensor is used to monitor the level of liquid in various tanks. These devices are used to prevent floods, to control the rise of water at dams and reservoirs; In everyday life they are used in washing machines, in the organization of water pipes and heating systems, etc.

Classification and description

Depending on the method of measurement, these devices can be divided into contact and non-contact. The water level sensor of the first type is located directly on the tank wall, it switches contacts when the liquid reaches the mark on which it is placed. In addition, the water level can be measured by the following methods: capacitive, magnetic, optical, ultrasonic, etc. The optical water level sensor has no moving parts, it is mounted on the wall of the tank and operates when the specified level is reached. The interruption of optical rays causes a change in the signal at the output of the device.

The water level sensor (float) is a universal precision device designed for a wide range of different applications requiring ultra-precise fluid flow measurements. Such devices are single- and multilevel, as well as linear (analog).

The contactless water level sensor can work with a variety of liquids, solids and materials with varying degrees of toxicity and viscosity. Such devices are divided into ultrasonic and capacitive devices.

Contact devices (level gauges) have contact with the liquid that they measure. They can be immersed in water (as radar or hydrostatic) or cut into the wall of the tank at a given height (optical, fork vibrating devices). They are optical, piezoelectric fork, radar or radar, hydrostatic and fiber optic.

How to make a water level sensor in a tank?

If you are not satisfied with products sold in stores, try to make such a device yourself, especially since it is quite simple. The sensor offered to your attention is used to control the level of liquid in various containers. At the signal of this device, the water pump or indicator is switched on or off. The device is an elementary direct current amplifier, which is made on two transistors. Trimmer resistor allows you to set the necessary sensitivity of the device. The transistors are protected by a semiconductor diode. The device provides an indication in the form of a single LED located on the collector of the first transistor. For the assembly we need the resistors (220 kΩ, 10 kΩ - 3 pcs, 1.2 kΩ), one capacitor (470 mkF / 50 V), two transistors (BC547), a diode (1N4001) and one LED. This circuit is powered by a constant voltage of 6-15V and consumes an electric current of 75 mA.

As a sensor, you can use plates made of foil-coated fiberglass (10 x 50 mm). They need to be set at a distance of 3 mm with foil inside.

Conclusion

Summarizing, we note that such devices are very useful, especially in the private sector. Judge for yourself: this sensor can be installed in the shower or bath tub, when organizing irrigation in the garden area, as well as in the water supply systems of your home.