Introduction

A soil humidity sensor measure and monitor the amount of water content in the soil. The conventional gravimetric measurement needs more time in a lab & also dedicated labor. A soil humidity sensor uses other properties like electrical resistance or dielectric constant to measure the moisture content. They are very handy for farmers and researchers. They are light-weighted small instruments that you can carry inside a bag.

How will a Soil Humidity Sensor help you?

A soil humidity sensor makes sure that you can keep track of the water content in your garden soil. The water content is measured throughout the length of the sensor. But, the sensor is the least sensitive at the edges.

If you are already into farming, you know how humidity will affect your plants. A soil humidity sensor tracks the humidity data of the soil and logs it. You can use Arduino or similar controllers to send the logged data to an external device as well.

Another type of sensor called tensiometer is available in the market as well. It measures the potential energy of the water. Water potential data helps in finding the optimum level of water needed for a particular soil type.

How does it work?

The soil humidity center uses capacitance to measure the dielectric constant. The sensor generates a voltage proportional to the dielectric constant value. When the moisture level is low, the dielectric value increases. Increased moisture outputs a low voltage at the sensor. This is how sensors analyze the moisture in its surroundings.

Any soil humidity sensor is a low power device. Their working voltage is 5V and an operating current less than 20mA. The optimum temperature for accurate measurement ranges from -40°C to +60°C for the high-end sensors. The interface is analog and a digital circuit uses this data to generate a humidity equivalent value.

It is crucial to understand the installation of the sensor to get an accurate reading. Choose a sensor that meets your requirement. You don’t need a high accuracy humidity sensor if you are using it in agriculture. But you cannot compromise on the accuracy if you are doing research. Different factors can affect the sensor reading and cause errors. It is advised to use multiple sensors to average the readings so that the value can be confirmed. A soil humidity temperature can be very helpful in controlled farming methods.