2.1.6 Joystick

Introduction

In this project, We’re going to learn how joystick works. We manipulate the Joystick and display the results on the screen.

Required Components

In this project, we need the following components.

Schematic Diagram

When the data of joystick is read, there are some differents between axis: data of X and Y axis is analog, which need to use ADC0834 to convert the analog value to digital value. Data of Z axis is digital, so you can directly use the GPIO to read, or you can also use ADC to read.

Experimental Procedures

Step 1: Build the circuit.

Step 2: Go to the folder of the code.

cd ~/raphael-kit/python-pi5

Step 3: Run.

sudo python3 2.1.6_Joystick_zero.py

After the code runs, turn the Joystick, then the corresponding values of x, y, Btn are displayed on screen.

Code

Note

You can Modify/Reset/Copy/Run/Stop the code below. But before that, you need to go to source code path like raphael-kit/python-pi5. After modifying the code, you can run it directly to see the effect.

#!/usr/bin/env python3
from gpiozero import Button
import ADC0834
import time

# Initialize the button connected to GPIO pin 22
BtnPin = Button(22)

# Setup the ADC0834 ADC
ADC0834.setup()

try:
    # Main loop to read and print ADC values and button state
    while True:
        # Read X and Y values from ADC channels 0 and 1
        x_val = ADC0834.getResult(0)
        y_val = ADC0834.getResult(1)

        # Read the state of the button (pressed or not)
        Btn_val = BtnPin.value

        # Print the X, Y, and button values
        print('X: %d  Y: %d  Btn: %d' % (x_val, y_val, Btn_val))

        # Delay of 0.2 seconds before the next read
        time.sleep(0.2)

# Gracefully handle script termination (e.g., via KeyboardInterrupt)
except KeyboardInterrupt:
    pass

Code Explanation

1. This section imports the Button class from the gpiozero library to manage a button connected to a GPIO pin. It also imports the ADC0834 library for interfacing with the ADC0834 ADC (Analog-to-Digital Converter) module.

   #!/usr/bin/env python3
   from gpiozero import Button
   import ADC0834
   import time
   

2. Initializes a button connected to GPIO pin 22 and sets up the ADC0834 module for usage.

   # Initialize the button connected to GPIO pin 22
   BtnPin = Button(22)
   
   # Setup the ADC0834 ADC
   ADC0834.setup()
   

3. The VRX and VRY connections of the joystick are linked to CH0 and CH1 of the ADC0834, respectively. This setup facilitates reading the values from CH0 and CH1, which are then saved in the x_val and y_val variables. In addition, the SW value of the joystick is read and assigned to the Btn_val variable. The retrieved values of x_val, y_val, and Btn_val are subsequently displayed using the print() function.

   try:
       # Main loop to read and print ADC values and button state
       while True:
           # Read X and Y values from ADC channels 0 and 1
           x_val = ADC0834.getResult(0)
           y_val = ADC0834.getResult(1)
   
           # Read the state of the button (pressed or not)
           Btn_val = BtnPin.value
   
           # Print the X, Y, and button values
           print('X: %d  Y: %d  Btn: %d' % (x_val, y_val, Btn_val))
   
           # Delay of 0.2 seconds before the next read
           time.sleep(0.2)
   
   # Gracefully handle script termination (e.g., via KeyboardInterrupt)
   except KeyboardInterrupt:
       pass