Water level indicator is a type of indicator which shows us level of water at each lavel by visualizing by LED or other display component . This Water level indicator with alarm circuit works as the water level of tank to what level reach and how much there rest amount of water in that tank using LED as visualize .we know that water is the good conductor of electric current , this property uses in this project and Indicators indicates the three level of water by conducting the current though water through wires which touches with it.
Circuit of water level indicator is so simple and used very less components required to make this circuit . Three NPN transistors , two low power relay , 3 LEDs and some resistors and diodes are used to make this circuit.
Working And Testing
1. At low level
When the water level is low and they reach to bottom level then the wire that is placed at low level is detecting the voltage and two other level wire is disconnecting , then the current flow through only lower wire and transistor Q1 will on and this transistor pass the supply to LED 1 and this LED will glow .only LED1 will glow and other will off .
2. At medium level
When water reaches medium level and touches the 2nd wire which is placed on that place , At this condition transistor Q2 will also ON and flows the current and activate the relay 1 . As soon relay 1 will activate the conduction between the base of transistor 1 and wire 1will break . At this time only LED 2 will glow and LED 1 off. At medium level only LED 2 glows because the base voltage of trabsistor disconnect by relay 1
3. At FULL level
Now Water level comes at full level and this touches the upper wire which placed for detection of full level and current conducts between water and the base pin of transistor Q3 and then activates relay 2, After activating the relay 2 the base voltage of transistor Q2 disconnected and LED 2 goes to off. At this condition only one LED (LED 3) glows and other leds in off.
A buzzer can connects to produce a warning sound with full level wire through a transistor .
At place of three different leds you can connect one tricolour LED of Common Anode .
Connect this circuit with 9v dc supply. All three LEDs are should be placed out at the near your living room for monitor the level of water tank.
BC547- 4 pcs
9v 1A relay-2
IN 4007 -2
LED– 3 (OR ONE common anode tricolor led)