Smart Drip Irrigation Solution for Arid Regions

Overview

In arid regions, the lack of freshwater poses a significant challenge for crop irrigation. But what if we could harness the power of technology to transform rainwater from the sky into a valuable irrigation resource? As shown in the figure below, drip irrigation technology can maximize the utilization of water resources. In arid regions, collecting rainwater and applying it to a drip irrigation system can significantly enhance the water absorption efficiency of crops, thereby promoting their growth and yield. This approach not only conserves valuable water resources but also helps to sustain agricultural production in environments where water is scarce.

In this lesson,we will collaboratively utilize sensors to create an smart drip irrigation device for arid regions.that combines rainwater collection and smart drip irrigation.The smart drip irrigation system can be divided into two parts: (1) Rainwater collection system: It collects rainwater and stores it in a tank, while continuously detecting and displaying the water level in the tank. (2) Automatic drip irrigation system: It activates the water pump to achieve automatic drip irrigation when it detects that the plants need watering.

Standards

NGSS-NEXT GENERATION SCIENCE STANDARDS-MIDDLE SCHOOL(MS)

Engineering Design
Life Science

The national curriculum in England

Plants
explore the requirements of plants for life and growth (air, light, water, nutrients from soil, and room to grow) and how they vary from plant to plant

Materials

Activity

1.Connection

Connect the sensors as shown in the picture below.

Connect the micro:bit to the computer.

2.Experiment One: How to Detect the Water Level in a Tank

(1)Get to Know Water Level Sensor

First, let's start by making the rainwater collection system.In the rainwater collection system, we use a water level sensor to continuously monitor the water level in the tank.

(2)Read Water Level

Open the programming website: https://makecode.microbit.org/.

Create a project named 'smart drip irrigation'

The water level sensor works based on the conductivity of water. As the water level rises, more wires are connected, causing the output voltage to increase, and the analog value also increases.Use the following code to read data from the water level sensor.

Click the three dots beside the download button, then click on Connect Device. Next, pair your micro:bit and click 'download'.

Insert the water level sensor vertically into the tank to detect the water level in real-time,as is shown below.

Click Show data Device  to observe the data from water level sensor.As shown in the figure, when there is no water in the tank, the data from the water level sensor is nearly 0.

Next, let's conduct an inquiry activity together. Add water to the tank and detect the data measured by the water level sensor when the water in the tank is at 1/5, 2/5, 4/5, and full of the tank's capacity. Also, observe the sensor reading when there is almost no water in the tank.
You can fill in the blank spaces with the actual sensor readings you obtain during your experiment.

(3)Display Water Level in Real Time 

Alright, I believe you have completed the table. My experimental results show that when the water in the tank is at 1/5, the water level sensor reads approximately 520. When the water level is at 2/5, the data is about 540. When the water level is nearly at 4/5, the value is about 560. When the tank is full, the value is approximately 570.And when there is almost no water in the tank,the value is always less than 10.

Based on the experimental results, we will continue programming to use the micro:bit LED matrix to display the current water level in the tank in real time. 

Use the following code to light up more LED lights on the matrix screen as the water level in the tank rises.             

(4)Observe the Running Effect 

Click the 'download' button.After the code is successfully uploaded, observe the actual effect.As shown in the figure, the higher the water level, the more LEDs on the matrix screen light up.       

In this way, we can determine the water level in the tank by observing the micro:bit's LEDs. When the water level is too low, we can add water to the tank in time.

3.Experiment Two:What Soil Moisture Level Requires Watering

In Experiment One, we successfully created the Rainwater Collection System. Next, let's work together to make the Automatic Drip Irrigation System. In the Automatic Drip Irrigation System, we use a soil moisture sensor to detect the moisture in the crop soil.

(1)Get to Know Soil Moisture Sensor

Soil moisture refers to the water content in the soil, which can directly affect the water supply to crops. Low soil moisture can lead to soil drought, reducing the efficiency of photosynthesis and affecting the yield and quality of crops.The soil moisture sensor can read the moisture in the soil and output an analog value ranging from 0 to 1023.

(2)Investigate the Optimal Soil Moisture Range for Different Plants

There is a that maps the soil moisture percentage to the sensor readings (0-1023).

Plants can be categorized into hygrophytes, xerophytes, and mesophytes. Soil moisture is not always better when higher; different plants have varying optimal soil moisture levels for growth. Please refer to the following information to find the most suitable soil moisture percentages and corresponding sensor values for the listed plants, and complete the table below

(3) Read Soil Moisture

Next, we will program to read soil moisture. Use the following code to read the soil moisture of the plant.

Click the 'download' button to download the code to micro:bit. 

(4)Observe the Running Effect 

Insert two-thirds of the soil moisture sensor into the flowerpot.

Click the ' show data Device' and then observe the data from the soil moisture sensor. As is shown below,through this, we can detect the moisture level of the plant's soil in real time. In this way, when the soil is relatively dry, we can water the plants in time to help them grow better.

(5)Write an Automatic Drip Irrigation Program

After determining the optimal soil moisture levels for different plants, we will continue to write the automatic drip irrigation program based on the water level program from Experiment One. The program will detect soil moisture, and when the current soil moisture is lower than the optimal level for the plant, it will activate the water pump.

The program is shown in the figure below. Taking tomatoes as an example, when the soil moisture for tomatoes is detected to be less than 614, pin2 outputs a high level to activate the water pump. Otherwise, it outputs a low level to turn off the water pump.

The program link: https://makecode.microbit.org/_cqcE5V94sfHw
 

Click the 'download' button.

4.Building

After writing the program, next, use building blocks to build a water tube hold with blocks.Please follow the drawing below to complete the building of the blocks.

Build it as shown below.

Next ,connect the water pump to the tube.Take out a 5cm long water tube and connect the water tube to the pump head as shown in the picture below.

Then, use the pipe connector to connect the 5cm water tube to a 11cm thin water tube.

Take out another 11cm long thin water pipe and cut it into two parts with scissors, one half is about 2cm long and the other half is about 9cm long.

    Connect the water tubes numbered 1,2, and 3 in the figure with a 3-way connector.

Install the two gas pressure regulators as shown below.

Place the water pump into the water tank (rainwater collection box) and add water to the tank to cover the water pump to simulate rain.Place the water tube on the hold as shown in the picture below.

Insert the pins into the holes of the T-shaped connectors and linear connectors.

Connect motor controller module to the water pump with boson cable(The motor control module is switched to terminal B)

Insert the water level sensor vertically into the tank to detect the water level in real-time.Insert the soil moisture sensor into the flowerpot to detect if the crops are experiencing water shortage.The assembled physical object is shown in the figure below.

Observation

Disconnect the micro:bit from the computer.Connect the Boson micro:bit mainboard and Battery holder.When the red indicator light comes on, the smart drip irrigation system begins to operate.

Congratulations, you have successfully created a smart drip irrigation system for arid regions.Watch the following video to understand how the smart drip irrigation system works.