Soil moisture detector circuits and automatic controller

These are soil moisture detector circuit projects, can build easy with PCB No.5 circuits and alarm with LED and buzzer, and controller as water for plants. I like planting trees, because trees are more useful to us.

However, I always have problems with moisture content of soil,Each plant needs water is not as same. Watering or soil moisture is not good. May cause damage to our trees. With these problems, I think the electronic system to solve this problem.

For example, to check moisture level of the soil.

We see from the outside, may not be good enough. Sometimes we see that the soil is dry. But it may be appropriate to plant moisture that, when we add water.

It may be possible to root rot. To determine these characteristics. It saves water, too. I collected several circuits below.

Other circuits are recommended:

Water pump controller circuit

1.) Automatic Watering for the tree

A trees should be taken care of as well. This circuit allows for watering trees, can be done automatically. When soil moisture levels decrease, to values that are defined.(Which can be determined by the resistance of R1.) A relay RY1 starts.

Automatic Watering for the tree

This relay can be used to control the alarm or Open water valve for watering plants. The probe used is a large copper wire or a metal rod with a length of about 120 mm.

On the end of each probe, attached to the insulation sheet, which is right size.(about 40 x 20 mm.) The probe should be straight and parallel bars, each separated by 15 mm. The VR1 to customize the sensitivity of the circuit.

2.) Moisture sensor circuit

This Check this dry soil circuit or soil moisture meter For the Blind. Because it will alert on clay. Circuit has less detail. It production the low frequency pulse, the IC CMOS CD4001 circuits is primary device,internal structure consists of NOR Gate.

Moisture sensor circuit

When added to RC circuit will be on low frequency oscillator. It is divided into two series, the first low frequency pulse generator. Then sent to another set. , A set of audio source through the C4 and then out to the speakers.You can apply the display devices as needed. Special about this circuit is to use solar cells as power supply to the circuit.Use only probes. Into the soil, we want to examine.

3.) Moisture Activated Relay by Bipolar Transistor

Today we try to build warn the moistness or Moisture Activated better. Or do go to use be warn it rains. Because of be the circuit is simple. Follow the circuit will think use Bipolar Transistor just one only.

Moisture Activated Relay by Bipolar Transistor

When measure touch the moistness make the electric current flows through to pin B of Q1 get then make it works. The Relay as a result work apply the work controls electric other appliances. By the rapidity of this circuit can control with R2 – 1M.

If you use power supply the size is 6V-9V. Should use Relay 6V-9V resistance coil sizes about 500ohm. For the transistor use 2N2222 or BC549 or C1815 etc. Then make the circuit s work well sir.

4.) LED Warning Water the plants using CD4093

Electronic users love trees. But no time and work and forget Enjoy water the plants.So the trees dry out.This circuit solves this problem.It also allows us to not water the plants with too often.

LED Warning Water the plants using CD4093

Operation of the circuit. When the supply to the circuit. IC1 / 1 (IC 4093) will work together R1, R2, D1 and C2 is the Oscillator generator.The output at Pin 11 is a rectangular pulse to IC1/2.To return the logic state is out of the opposite pin 3.In addition, the signal from the pin 11 will be issued to the temple ground. be test point A and test point B.It will be resistance.Make a signal to stimulate IC1/3, IC1/4.Which is parallel to the current output is high enough to make the LED light.

The signal from IC1 / 2 VR1 is a fine stream that flows into IC1 / 3 and IC1 / 4. To suit the soil to measure.If the ground for us to measure the humidity Li LED1 will light extinguishes.And if the ground is dry LED1 light depending on adjustments VR1.


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18 thoughts on “Soil moisture detector circuits and automatic controller”

  1. Please help me to source two kits shown above. They are #1 Automatic watering a tree

    #4 Moisture Activated Relay by Bipolar Transistor

    My students need them…help!

  2. Hey. I’ve come up with an idea for an automated watering system for my greenhouse. it will cost me nothing to run but I need a soil moisture sensor, a very basic one that has a led that lights up when the soil is fairly dry. this led i will de-solder and attach to an amplifier and electronic switch that will imput current into a water pump upon the sensor activating the circuit. if you know where i can get a cheap basic sensor like this, preferably 9v then email me at the address provided. many thanks,


  3. thank you for this nice idea, can i get a full operational notes, and where on the plant soil moisture meter and automatic controller circuit can i connect the water pump circut?

  4. Hellow sir, im planning to do a mimiproject on plant moisture control. Can u please send i detail operation of the circuit to my thanks. Its urgent…

    Thanks and regards,

  5. hi, can i know how the circuit “LED warning water the plants with ic 4093” works?? i’m not clear with the explanation above.


  6. hi sir/mam ,can i get the circuit for soil resistance measurement for the following condition
    1.soil have high resistance when it is dry and
    2.soil has very low resistance when it is wet.
    plz send me project of this and also the details of this project…………. plz sendtomy email id sir/mam

  7. sir , can you provide me with a circuit diagram in wich moisture sensor controls a stepper motor ratation (forward and reverse)

  8. Sir
    please Can you help me with details explanation in each stage of the plant Soil moisture meter? please is urgent

  9. i have tested the the circuit in the first post using soil with different moisture and 12v relay to drive a solonoid valve. one there is a resistivty difference among the sample soils the circuit perfectly does with the right material.

  10. Automatic watering a tree, Moisture sensor circuit, LED warning water the plants with ic 4093. can i get full explanations for this circuit… i need your help..

  11. Dear all

    I have been interested in this Web that increase my knowledge in different circuit. But can can you advise me on my project title
    Automatic watering system because am a farmer what I want to establish to my vegetable garden.

  12. Is 1N914 is azenner diode??

    Are we using to regulate voltage or to direct current?

    Is there need of specific transistor..
    Plzz reply fast!!!
    Hope u understand!!!

  13. In automatic watering tree project the circuit works in opposite way.. When soil moisture decrease, the relay turn off and when soil moisture increase, the relay turns on.. Pls change and upload proper pin out..


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