5.11 Toggle the Joystick

If you play a lot of video games, then you should be very familiar with the Joystick. It is usually used to move the character around, rotate the screen, etc.

The principle behind Joystick’s ability to allow the computer to read our actions is very simple. It can be thought of as consisting of two potentiometers that are perpendicular to each other. These two potentiometers measure the analog value of the joystick vertically and horizontally, resulting in a value (x,y) in a planar right-angle coordinate system.

The joystick of this kit also has a digital input, which is activated when the joystick is pressed.

Required Components

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

ESP32 Starter Kit

320+

ESP32 Starter Kit

You can also buy them separately from the links below.

COMPONENT INTRODUCTION

PURCHASE LINK

ESP32 WROOM 32E

BUY

ESP32 Camera Extension

-

Jumper Wires

BUY

Joystick Module

BUY

  • Available Pins

    Here is a list of available pins on the ESP32 board for this project.

    For Analog Input

    IO14, IO25, I35, I34, I39, I36

    For Digital Input

    IO13, IO14, IO27, IO26, IO25, IO33, IO4, IO18, IO19, IO21, IO22, IO23

  • Strapping Pins (Input)

    Strapping pins are a special set of pins that are used to determine specific boot modes during device startup (i.e., power-on reset).

    Strapping Pins

    IO5, IO0, IO2, IO12, IO15

    Generally, it is not recommended to use them as input pins. If you wish to use these pins, consider the potential impact on the booting process. For more details, please refer to the Strapping Pins section.

Schematic

../../_images/circuit_5.11_joystick.png

The SW (Z-axis) pin is connected to IO33, which has a built-in 4.7K pull-up resistor. Therefore, when the SW button is not pressed, it will output a high level. When the button is pressed, it will output a low level.

I34 and I35 will change their values as you manipulate the joystick. The range of values is from 0 to 4095.

Wiring

../../_images/5.11_joystick_bb.png

Code

Note

  • Open the 5.11_joystick.py file located in the esp32-starter-kit-main\micropython\codes path, or copy and paste the code into Thonny. Then, click “Run Current Script” or press F5 to execute it.

  • Make sure to select the “MicroPython (ESP32).COMxx” interpreter in the bottom right corner.

from machine import ADC,Pin
import time

xAxis = ADC(Pin(34, Pin.IN)) # create an ADC object acting on a pin
xAxis.atten(xAxis.ATTN_11DB)
yAxis = ADC(Pin(35, Pin.IN)) # create an ADC object acting on a pin
yAxis.atten(yAxis.ATTN_11DB)
button = Pin(33, Pin.IN, Pin.PULL_UP)

while True:
    xValue = xAxis.read()  # read a raw analog value in the range 0-4095
    yValue = yAxis.read()  # read a raw analog value in the range 0-4095
    btnValue = button.value()
    print(f"X:{xValue}, Y:{yValue}, Button:{btnValue}")
    time.sleep(0.1)

When the program runs, the Shell prints out the x, y, and button values of joystick.

X:1921, Y:1775, Button:0
X:1921, Y:1775, Button:0
X:1923, Y:1775, Button:0
X:1924, Y:1776, Button:0
X:1926, Y:1777, Button:0
X:1925, Y:1776, Button:0
X:1924, Y:1776, Button:0

  • The x-axis and y-axis values are analog values that vary from 0 to 4095.

  • The button is a digital value with a status of 1(release) or 0(press).

    ../../_images/joystick_direction.png