Liquid Level Sensor | Water Level Sensor



Liquid Level Sensor is an electronic setup which indicates the level of liquid in a certain tank. Accuracy of the sensor depends on the sensing method. A simple setup includes a set of sensors, (which may be pressure sensors, optical sensors, capactive sensors of conductive sensors), a controller (PIC, 8051 or Audrino) and a display. There are different methods to sense the level of liquid. Some are listed below:

Sensing Methods

  • Capactive Sensors: In this method, two metal plates are implanted inside the liquid tank. The capacitence of plates change when air between plates is replaced by liquid. That difference of capacitence is measured to estimate the level of liquid in the tank.
  • Optical Sensors: Optical Sensors (like infrared) may be used to detect whether liquid is present between pair of transmitter-receiver or not. This method does not give precise measurement. It just idnicates presence of liquid at certain level in the tank.
  • Pressure Sensors: The method is particularly useful for precise measurement of quantity of liquid. Pressure sensor is installed at the bottom of tank. It gives a pressure reading depending on the quantity of liquid in the tank. If one know the denstity of liquid, she can easily get the precise measurement of level of liquid.
  • Floating Stick: A float is attached to a stick. Stick goes up as the liquid rises in the tank. Displacement of the stick is measured to estimate the level of liquid.

Useful Links

Previously Done By

  • "Liquid Level Sensing System using SCADA" by Javier García Fernández at Glynd┼Ár University (Session 2010-11)

Supervised by: Reg Holme