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AUTOMATIC PLANT IRRIGATION SYSTEM

Title:
AUTOMATIC PLANT IRRIGATION SYSTEM
Circuit: 
     [ Note: If circuit diagram is not clear then you may zoom using ctrl and '+' .]
COMPONENTS :
  • Capacitor (C4) = 10u 16V.
  • Capacitor (C5) = 0.01u.
  • Resistor (R3) = 27K
  • Resistor (R4) = 27K
  • Diode (D1 and D2) = IN4148
  • Relay = 6V, 150 ohms

DESCRIPTION :
               Imagine if plants are watered automatically and regularly. One does not need to look into it always .Just turn on this system and its done.

               Circuit is simple. Soil has high resistance when it is dry and has very low resistance when it is wet. We insert two probes in the soil in such a way that that they will conduct when the soil is wet and they will not conduct when the soil is dry. So, when the probes do not conduct, system will automatically detect this condition, and can start watering plants. Now how exactly it does that ?

Circuit Description:
  •           Two probes which are connected to the circuit are placed into the soil. The two probes will conduct only when soil is wet (resistance is low) and they cannot conduct when soil is dry due to high resistance. The voltage is given to the probes to conduct is given from a 9v battery connected to the circuit.
  •      When the soil is dry it will produce large voltage drop due to high resistance. This is sensed by 7404 hex inverter and makes the first NE555 timer trigger which is configured as monostable multivibrator with the help of an electrical signal.
  •       When the first NE555 is triggered at pin 2, it will generate the output at pin 3 which is given to the input of second NE555 timer. The second 555 timer is configured as astable multivibrator which got triggered by the first 555 timer and will generate the output and drive the relay which is connected to the electrically operated value through the transistor SK100. You can use a heat sink for SK100 transistor if it is dissipating more heat.

  •      The output of second NE555 timer will switch on the transistor SK100 which will drive the relay. Relay which is connected to the input of electrical value and output of value is given to the plant plots through the pipe.
APPLICATIONS:
  •    This system can be used in farms, for regular supply of water.
  • This can be used in homes where people have gardening as a hobby. Especially when they are not present at home.