2.8 Smart Water Tank

In this project, we use a water level sensor module and a servo to simulate a smart water tank. The water level sensor is fixed inside the tank to measure the water level, and when the water level is below a threshold, the valve controlled by the servo is allowed to open to let water in.

Component List

  • Raspberry Pi Pico W x1

  • MicroUSB cable x1

  • 830 Tie-Points Breadboard x1

  • Servo x1

  • Water Level Sensor Module x1

  • Jumper Wire Several

Wiring

../_images/Water_Tank_Wiring.png

Pico W has three GPIO pins that can use analog input, GP26, GP27, GP28. That is, analog channels 0, 1, and 2. In addition, there is a fourth analog channel, which is connected to the built-in temperature sensor and will not be introduced here.

../_images/Water_Tank_Wiring2.png

  • S of water level sensor is connected to GP26(A0), + to VBUS, - pin to GND.

  • The orange wire (signal) of the servo is connected to GP15, the red wire (power) is connected to VBUS, and the brown wire (ground) is connected to GND.

Code

Note

  • Utilize the visual programming interface shown below through drag-and-drop methodology.

  • Import 2.8_Smart_Water_Tank.png from the location Ultimate-Starter-Kit-for-Pico-W\Piper_Make. For complete instructions, reference Loading Existing Projects.

../_images/Water_Tank_Code.png

Following Pico W connection, activate the Start button to initiate program execution. Position your hand above the ultrasonic sensor to observe corresponding variations in the LED bar graph illumination pattern.

How it Works?

../_images/Water_Tank_Code2.png

Set the rotation speed of pin15 (servo) to 15%.

  • [servo pin() set speed to ()%]: Used to set the rotation speed of the servo pin, the range is 0%~100%.

../_images/Water_Tank_Code3.png

Reads the value of pin A0 and stores it in the variable [water_level].

  • [set (water_level) to]: Used to set the value of the variable, you need to create the variable from the Variables palette.

  • [read voltage from pin ()]: Used to read the voltage of the analog pins (A0~A2), the range is 0 ~ 3.3V.

../_images/Water_Tank_Code4.png

Set the voltage threshold to 1. When the voltage of water level sensor is less than 1, let the servo rotate to 180° position, otherwise rotate to 0° position.

  • [servo pin () set angle to ()]: Set the angle of servo pin to, the range is 0 ~ 180°.