Soil Moisture Detector

Many of us go out of home for many days and in your absence there is nobody to look out for you plants. And sometimes your plant died because of insufficient water supply. So to solve this problem we have described a simple soil moisture detector circuit which will take care of your plants by providing them water on time so that when you go out you feel relax that your plant is safe. This circuit will sense the presence of moisture in soil and if moisture is not sufficient it will automatically switch on the pump connected with the relay to on the water supply in plants.

[[wysiwyg_imageupload:11130:]]

Fig. 1: Prototype of Soil Moisture Detector Circuit on Breadboard

This simple soil moisture detection circuit is based on commonly available IC 7404, relay and few more components. CD7404 is an inverter IC which contain 6 individual NOT Gate on a single IC. It’s outputs goes low when input is high. And its output becomes high when input is low that’s why it is known as inverter IC.

Moisture level is sensed by probes which are embedded in the soil. Be careful while inserting the probes they should inserted into a suitable depth and probes should be separated from each other. When there is no moisture in soil Pin 1 of IC1 becomes low because of this output pin 2 goes high.

And the transistor connected through R1 conduct because of that motor connected with relay starts and water is provided to plant.

When sufficient amount of water is given to plant soil become moist and pin 1 of IC1 goes high which make pin 2 of IC1 low and the motor connected with the relay stop working because transistor is now in cut off mode and does not conduct. So you can easily make this simple circuit and install in your garden when you go out from your homes.