Water Level Measurement Using Capacitive Sensor

Liquid level sensing is based on the theory of a ratiometric measurement using three sensors as shown in figure 2.

Water level measurement using capacitive sensor.

The space between the tubes is the dielectric. When the tube is empty the space is occupied by air. When the tube starts to fill more and more of the space will be occupied by water. The capacitive level sensor has the 2 conducting plates in the form of 2 electrically isolated aluminium tubes a smaller tube in a larger tube.

With a capacitive sensing based solu tion no moving parts or sensors need to be in direct contact with the liquid to be measured. Instead the liquid level is measured with a non contact capacitive sensor deployed externally to the reservoir. ε r eff 1 ε r 2. Level the capacitance of the level electrode is proportional to the liquid height hw.

1 have described the design and implementation of a liquid level measurement system based on a remote grounded capacitive sensor. 2 2 liquid level capacitive sensing 16 2 2 1 liquid level coplanar plate capacitive sensors 16 2 2 2 differential and ratiometric measurement of liquid level 19 2 2 3 active shielding 21 2 2 4 out of phase liquid level technique 23 2 3 fdc1004 capacitance to digital conversion 25 2 4 i2c data transfer between mcu and fdc1004 26. From this equation the measured capacitive is proportional to the length submerged into water as the approximate capacitance per length of track for a coplanar sensor remains constant. Capacitive sensor for water level detection has been fabricated.

This sensor comprises a printed circuit board pcb with configuration of two interpenetrating comb electrodes. There are two types of capacitive level sensor contact type or non contact type for water level measurement. A rod of stainless steel and a polytetrafluoroethylene ptfe insulated wire have been used for electrode of capacitive sensor. Also capacitive sensor is a noncontacting device in the common usage.

Performing system calibration using labview software can help achieve higher accuracy. 5 v pp3. In this research water level sensor based on capacitive principal created using two copper plates with height h width b and distance l between two plates respectively 0 040 m 0 015 m. In this research water level sensor based on capacitive principal created using two copper plates with height h width b and distance l between two plates respectively 0 040 m 0 015 m and 0 010 m.

For d h 1.