Water Level Indicator With 7-Segment Display PCB

Posted on Feb 4, 2014

Circuits available for indicating water level is usually consist of LEDs to indicate the liquid level. But this circuit uses a 7-segment LED display instead of normal LED`s for numeric display of water level. Moreover, a buzzer is used to alert you of water overflowing from the tank. The circuit shows the water level by displaying L, H and F for lo

Water Level Indicator With 7-Segment Display PCB
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w, half and full, respectively. You can use this circuit for water tank motor control or a stand alone circuit. pins of IC 7404 (NOT gate IC) are pulled high via a 1M ohm resistor. So it outputs a low voltage. As water starts filling the tank, a low voltage is available at the input pins of the gate and it outputs a high voltage. When the water in the tank rises to touch the low level sensor, pin 5 of gate N3 gets a low voltage and results in high output at pin 6. Pin 6 of the gate is connected to pin 10 of gate N9, so pin 10 also goes high. Now as both pins 9 and 10 of gate N9 are high, its output pin 8 also goes high. As a result, positive supply is applied to DIS3 and it shows L` indicating low level of water in the tank.

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