Soil Moisture Monitoring System

Environmental monitoring is a significant driver for wireless sensor communication. Its potential to provide dynamic real-time data about monitored variable will enable to measure properties that have not previously been observable. A low cost consumer version soil moisture monitoring system was bui

Project Title

Soil Moisture Monitoring System

Project Area of Specialization

Artificial Intelligence

Project Summary

Environmental monitoring is a significant driver for wireless sensor communication. Its potential to provide dynamic real-time data about monitored variable will enable to measure properties that have not previously been observable. A low cost consumer version soil moisture monitoring system was built using a gypsum block to take moisture readings, a peripheral interface controller (PIC) with a built-in transmitter as sensing unit, and a transmitter for wireless communication. The design of the overall system is based on: the system must provide consistent soil moisture measurements at low cost; the system must interface with an irrigation system to allow for automatic watering of the soil; and the measurement units must be unobtrusive to everyday activity. The system was tested so that it could be implemented with existing sprinkler systems. This system would conserve more water than the traditional timers that are in place on most irrigation systems today. In cases where the homeowner or user does a large amount of watering, there can be a substantial savings in water consumption with the low cost soil moisture monitoring system. While the prototype realizes all the goals that were set forth, the addition of other options would be beneficial to the marketability of the system. One option should be the implementation of other sensors such as a barometer and temperature sensor. These will allow the microcontroller to determine more accurately the optimum watering times. Also, reverting back to the original design that used a PIC with an integrated transmitter would reduce both the cost and the size of the sensing unit. While the current implementation works, a more user friendly interface, such as a PC interface, might be more desirable for some users.

Project Objectives

To automatically optimize use of water in food production through soil moisture based irrigation system

Specific objectives

• To determine the efficiencies of moisture measuring instrument.

• To calibrate sensors, tensiometers, and dielectric probe to measure moisture content.

• To automatically measure and adjust plant growth parameters using closed-loop feedback mechanism.

Project Implementation Method

Nowadays sensor technology is one of the fastest growing technologies. A sensor is a device capable of detecting a change in the physical or chemical environment which then converts it into electrical signals both electric current and voltage. The receiver used is also made by Linx technologies and is the companion to the transmitter, the RXM-315-LR. An identical ¼ wavelength antenna was used at this station. This receiver is always on sending information to the PIC. The PIC then determines which part of this information is noise and which part is the actual data that is transmitted. The main station microcontroller needs to have several I/O pins, a large amount of memory, a DIP configuration, and a local knowledge base. Based on these specifications the 16F74 was selected. The power supply consists of an AC-DC converter and a power regulator. The converter was a 9V DC output converter. The power regulator was a standard 7805 5V DC regulator. The main station circuit board was wire wrapped as opposed to etching as the sensing unit was. A ¼” hole was drilled in the top of the case for the antenna.

Benefits of the Project

In order to overcome the challenges of soil, farmers need to be equipped and updated with new improved production practices through research and extension services strategies that are climate smart. Solar energy remains the most reliable, renewable enviremental friendly source of energy, which needs to be integrated into modern day farming technologies. Automated drip irrigation system has proven to be water efficient in optimizing agricultural production. Fertigation process allows fertilizer to be applied at the root zone in the right proportion through the irrigation system. Irrigation and fertigation management is one of the main determining factors of quality and productivity in agribusiness. The advancement of technology has allowed development of various methodologies for monitoring soil moisture status automatically to irrigate without human intervention. This research proposes a system has great capacity in water savings compared to traditional methods of irrigation scheduling and fertilization. Intelligent smart farming system is such that pH control, nutrient supply and plant water requirement supply is monitored and adjusted automatically through use of sensors and closed-loop feedback system. Further work by Rahali et al.  supports this claim that electronic system achieves the control and remote monitoring of greenhouse solutions, in particular drip irrigation stations. This system uses a preprogrammed setup to collect real time data in the environment through sensors. Modern irrigation incorporates the use of Micro controller mechanism, which gives the farmer real time update on irrigation activities. This automation technology has closed-loop feedback mechanism were soil pH, fertigation and soil moisture content is controlled, monitored and adjusted accordingly. This project proposes a research on the experimentation and development of a fully automated moisture based irrigation system, nutrient solution application and monitoring of pH using a computerized feedback loop system in open field. There is need to measure the efficiencies of calibrate sensors, tensiometers, and dielectric probe in monitoring soil moisture efficiently and effectively. The irrigation will be carried out according to the moisture content deficit and compare the yields per unit area for the different devices. The core reason for irrigating according to moisture content deficit is to maintain the optimum amount of moisture the plant requires and still retain the same or increase yield while cutting costs of production.

Technical Details of Final Deliverable

Sensor technology is also related to wireless technology, this technology is known as wireless sensor network (WSN). Wireless sensors are standard measurement devices that measure one or more physical quantities and use transmitters equipped with the conversion of measured physical quantities into radio signals and transmit radio signals through a communication model. The radio signal is interpreted by the receiver or electronic instrument which
then converts the wireless radio signal into the desired output. The role of wireless sensor technology can be applied in human life to help people obtain information quickly and more accurately. One application that can be done by this technology is in the application of soil moisture sensors. This sensor will provide information about the moisture content in the soil. The analysis indicated that the gypsum block is a viable choice to take soil moisture readings. The gypsum block, , is a cylindrical block of gypsum in which two electrodes are inserted. The gypsum is porous and allows water to move in and out of the block as the soil wets and dries. When the block is excited electrically, ions move to the respective electrodes establishing an effective block resistance. A greater amount of water in the block equals more ions and a lower resistance to electrical current flow. Based on documentation provided by the manufacturer of the gypsum block, it was decided that an oscillator circuit should be used to prevent polarization. The signal generated by the oscillator was used in conjunction with a voltage divider to obtain measurements from the sensor. As the effective resistance of the sensor increased, the voltage across the limiting resistor in the voltage divider circuit decreased. After doing extensive research during the initial design phase, a PIC microcontroller with a built in transmitter was selected for the sensing unit. This PIC had many useful features such as a built in analog to digital converter (A/D), a built in oscillator, and the built in transmitter. However, a proven wireless system that was already implemented was found on an evaluation board in the instrumentation lab. This wireless system was produced by Linx and included several different transmitters and receivers available at different ranges and frequencies. These batteries are connected in series and provide a total of 6 volts to the microcontroller. This voltage is within the operating voltage range as specified by the manufacturer.  The sensor case is constructed from a 12” section of 3” diameter schedule 40 PVC pipe. The circuit board is held inside by cutting two rings from the same material and cutting sections of the ring out. This allowed the rings to be compressed enough to enter the pipe. 

Final Deliverable of the Project

HW/SW integrated system

Type of Industry

IT

Technologies

Artificial Intelligence(AI)

Sustainable Development Goals

Quality Education

Required Resources

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