The project, titled “Soil Moisture Detection and Alert System Using LM358 Comparator,” is designed to monitor the moisture level in soil and alert the farmer when the soil becomes dry or reaches a predefined moisture condition. The system uses soil moisture detection probes to sense the water content in the soil. The sensor output is fed to an LM358 operational amplifier configured as a comparator, which continuously compares the sensor voltage with a predefined reference voltage. Based on the comparison, the comparator generates a HIGH or LOW logic output according to the soil moisture level. This output is used to activate a buzzer, providing an audible alert to the farmer when the soil moisture reaches the set threshold. The system is simple, low-cost, and easy to implement, making it suitable for small-scale agricultural applications, home gardens, and plant monitoring. It helps farmers identify soil moisture conditions in a timely manner and supports efficient irrigation management while reducing unnecessary water usage.          

The major features of this project are:  

1. Sensor based automatic moisture level detection.
2. Simple electronic circuit.
3. Low moisture alerts using Buzzer.

         

The major building blocks of this project are:  

1. 9V Battery Power Supply.
2. LM358 Comparator.
3. Soil moisture sensor.
4. POT.
5. Reference voltage (Potentiometer).
6. LEDs.
7. Resistor.

           

Block Diagram:            

video: