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2.14 Water Level Detection

In this lesson, we will learn how to use a water sensor with the Raspberry Pi Pico 2 to detect the presence of water or measure the water level. This sensor is commonly used in projects related to rainfall detection, water level monitoring, and liquid leakage alerts.

How the Water Sensor Works

The water sensor has a series of exposed parallel wire traces that detect water droplets or measure the volume of water. As water comes into contact with these traces, the sensor outputs an analog signal. The more water that comes into contact with the sensor, the higher the output value, which can be read by the Raspberry Pi Pico 2’s analog-to-digital converter (ADC).

• Do not fully submerge the sensor in water. Only the area with the exposed traces should come into contact with water.

• Using the sensor in a humid environment while powered may cause the probe to corrode faster, so it is recommended to power the sensor only when taking readings.

What You’ll Need

In this project, we need the following components.

It’s definitely convenient to buy a whole kit, here’s the link:

Name	ITEMS IN THIS KIT	LINK
Newton Lab Kit	450+	Newton Lab Kit

You can also buy them separately from the links below.

SN	COMPONENT	QUANTITY	LINK
1	Raspberry Pi Pico 2	1	BUY
2	Micro USB Cable	1
3	Breadboard	1	BUY
4	Jumper Wires	Several	BUY
5	Water Level Sensor Module	1

Circuit Diagram

Wiring Diagram

Writing the Code

We’ll write a simple MicroPython program to read the analog value from the water sensor and print it to the console. As the water sensor is submerged, the value read by GP28 will increase.

Note

• Open the 2.14_feel_the_water_level.py from newton-lab-kit/micropython or copy the code into Thonny, then click “Run” or press F5.

• Ensure the correct interpreter is selected: MicroPython (Raspberry Pi Pico).COMxx.

import machine
import utime

# Initialize ADC on GP28
sensor = machine.ADC(28)

while True:
    # Read the analog value from the sensor
    value = sensor.read_u16()
    print("Water level reading:", value)
    utime.sleep(0.2)  # Delay to avoid flooding the console with data

When the code is running, slowly submerge the water sensor into water, watching the values printed to the console. As the sensor detects more water, the printed value will increase.

Learn More: Using the Sensor for Leak Detection

We can also use the water sensor to detect liquid leakage by treating it like a digital sensor. Here’s how:

1. Measure the Baseline Value:

   • First, take a reading from the water sensor in a completely dry environment. Record this value to use as a threshold.

   • If the sensor’s reading goes above the baseline threshold, we can assume that the sensor is in contact with water, indicating a potential leak.

2. Leak Detection Code:

   In this example, we’ll check if the sensor’s reading exceeds the threshold value (which you’ll need to set based on your environment).

   import machine
   import utime
   
   # Initialize ADC on GP28
   sensor = machine.ADC(28)
   
   # Set a threshold value based on dry readings (adjust as needed)
   threshold = 30000
   
   while True:
       # Read the analog value from the sensor
       value = sensor.read_u16()
   
       # Check if the value exceeds the threshold, indicating water exposure
       if value > threshold:
           print("Liquid leakage detected!")
   
       utime.sleep(0.2)  # Delay for readability
   

   The program checks if the sensor’s value exceeds a predefined threshold. If the value is higher, it prints a message indicating water or liquid leakage.

Practical Applications

• Leak Detection: Place the sensor near water pipes, and it can alert you if a pipe starts leaking.

• Water Level Monitoring: Use the sensor in tanks or containers to monitor the water level and trigger alerts or actions.

• Rain Detection: Install the sensor outdoors (with appropriate protection) to detect rainfall.

Conclusion

The water sensor is a simple yet powerful tool for detecting water levels or potential liquid leakage. By integrating it with the Raspberry Pi Pico 2, you can create responsive and useful water detection systems for a variety of applications.