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Water level alarm using 555 Timer

The shortage of underground water is primary issue these days and the water stored in water tanks are wasted due to overflow.

A water level indicator can be implemented with various circuits but here we are going to use a simple 555 Timer with few basic electrical components. 

components Required :

  1. NE555 Timer
  2. Resistors (R1,R4-1K / R2-22k / R3-570 Ohm)
  3. Capacitor (1uF)
  4. Buzzer
  5. Connecting wires
  6. Bread Board

Working :

The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation, and oscillator applications. The 555 can be used to provide time delays, as an oscillator, and as a flip-flop element. Derivatives provide two (556) or four (558) timing circuits in one package.

The circuit uses a 555 timer in astable mode. The approx frequency of the given astable circuit is around 60-62 Hz.

The two probes M1 & M2 which are metal piece should be kept at the high level for the water. The distance between the probes should be less than a few centimetres to ensure that the conduction between the probes will take place when water is touched to these probes. 

When the water level rises to the height of the probes, then the 555 circuit will get enabled and the output of the 555 timer produces a square wave output with a frequency of about 62 Hz. This output is given to the buzzer.

The logic Implemented in this circuit is, 555 timer is enabled when its reset pin is connected to logic high. But initially it is connected to ground. When the water level is maximum this pin is enabled and this drives the 555 timer into astable mode. 

Note : The two probes must be isolated from the metal body of the tank if have any.


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