ESP32 MicroPython Button Debounce
Sometimes, when you connect a button to an ESP32, it might seem like the button is pressed many times when you only press it once. This is because the button can quickly switch between being pressed and not pressed. This is called bouncing, also known as chattering. Bouncing can cause problems in your program.
This guide will show you how to fix this problem for ESP32 by using a technique called debouncing with MicroPython. Debouncing helps the ESP32 recognize a single button press as just one press.
We will learn though the below steps:
- ESP32 MicroPython code without debouncing a button.
- ESP32 MicroPython code with debouncing a button.
- ESP32 MicroPython code with debouncing for multiple buttons.
Hardware Preparation
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables.
Additionally, some of these links are for products from our own brand, DIYables.
Wiring Diagram
- How to connect ESP32 and button using breadboard
This image is created using Fritzing. Click to enlarge image
- How to connect ESP32 to a panel-mounted button using screw terminal block breakout board
This image is created using Fritzing. Click to enlarge image
Let's compare the ESP32 MicroPython code without and with debouncing to see how debouncing affects the behavior.
ESP32 - Button without Debounce
First, let's examine the MicroPython code for ESP32 without debouncing to understand its behavior.
"""
This ESP32 MicroPython code was developed by newbiely.com
This ESP32 MicroPython code is made available for public use without any restriction
For comprehensive instructions and wiring diagrams, please visit:
https://newbiely.com/tutorials/esp32-micropython/esp32-micropython-button-debounce
"""
from machine import Pin
import time
BUTTON_PIN = 21 # The ESP32 pin GPIO21 connected to the button
# Setup the button pin. The Pin.PULL_UP enables the internal pull-up resistor.
button = Pin(BUTTON_PIN, Pin.IN, Pin.PULL_UP)
# Initialize the previous state of the button
prev_button_state = 1 # Assuming the button is unpressed initially
while True:
# Read the current state of the button
button_state = button.value()
# Check if button was released
if prev_button_state == 0 and button_state == 1:
print("The button is released")
# Check if button was pressed
if prev_button_state == 1 and button_state == 0:
print("The button is pressed")
# Save the current state as the previous state for the next loop iteration
prev_button_state = button_state
Detailed Instructions
Here’s instructions on how to set up and run your MicroPython code on the ESP32 using Thonny IDE:
- Make sure Thonny IDE is installed on your computer.
- Confirm that MicroPython firmware is loaded on your ESP32 board.
- If this is your first time using an ESP32 with MicroPython, check out the ESP32 MicroPython Getting Started guide for step-by-step instructions.
- Connect the button to the ESP32 as shown in the diagram.
- Connect the ESP32 board to your computer with a USB cable.
- Open Thonny IDE on your computer.
- In Thonny IDE, go to Tools Options.
- Under the Interpreter tab, choose MicroPython (ESP32) from the dropdown menu.
- Make sure the correct port is selected. Thonny IDE usually detects it automatically, but you might need to select it manually (like COM12 on Windows or /dev/ttyACM0 on Linux).
- Copy the provided MicroPython code and paste it into Thonny's editor.
- Save the code to your ESP32 by:
- Clicking the Save button or pressing Ctrl+S.
- In the save dialog, choose MicroPython device.
- Name the file main.py.
- Click the green Run button (or press F5) to execute the script.
- Press and hold the button for a few seconds, then release.
- Check out the message in the Shell at the bottom of Thonny IDE.
Shell x
>>> %Run -c $EDITOR_CONTENT
MPY: soft reboot
The button is pressed
The button is pressed
The button is pressed
The button is released
The button is released
MicroPython (ESP32) • CP2102 USB To UART Bridge Controller @ COM12 ≡
As you can see in the log, you pressed the button only once, but the ESP32 detected multiple presses.
ESP32 Debounce for a Button
"""
This ESP32 MicroPython code was developed by newbiely.com
This ESP32 MicroPython code is made available for public use without any restriction
For comprehensive instructions and wiring diagrams, please visit:
https://newbiely.com/tutorials/esp32-micropython/esp32-micropython-button-debounce
"""
from DIYables_MicroPython_Button import Button
import time
# Initialize buttons connected to GPIO pins GPIO21
button = Button(21)
button.set_debounce_time(100) # Set debounce time to 100 milliseconds
while True:
button.loop()
if button.is_pressed():
print("The button is pressed")
if button.is_released():
print("The button is released")
Detailed Instructions
- In Thonny IDE, navigate to the Tools Manage packages on the Thonny IDE.
- Search “DIYables-MicroPython-Button”, then find the Button library created by DIYables.
- Click on DIYables-MicroPython-Button, then click Install button to install Button library.
- Copy the given code and paste it into the Thonny IDE's editor.
- Save the script on your ESP32 board.
- Click the green Run button (or press F5) to start the script. The script will start running.
- Press the button.
- Check out the message in the Shell at the bottom of Thonny IDE.
Shell x
>>> %Run -c $EDITOR_CONTENT
MPY: soft reboot
The button is pressed
The button is released
MicroPython (ESP32) • CP2102 USB To UART Bridge Controller @ COM12 ≡
You pressed the button once, and the ESP32 correctly identified it as a single push and release, with no additional disturbances.
※ NOTE THAT:
Different apps use different DEBOUNCE_TIME settings. Each app might have its own specific value.
ESP32 Debounce for multiple Buttons
Let's add debouncing to four buttons using ESP32 with MicroPython. Here's how to connect them to your ESP32:
This image is created using Fritzing. Click to enlarge image
"""
This ESP32 MicroPython code was developed by newbiely.com
This ESP32 MicroPython code is made available for public use without any restriction
For comprehensive instructions and wiring diagrams, please visit:
https://newbiely.com/tutorials/esp32-micropython/esp32-micropython-button-debounce
"""
from DIYables_MicroPython_Button import Button
import time
button_1 = Button(25) # Initialize buttons connected to ESP32 pin GPIO25
button_2 = Button(26) # Initialize buttons connected to ESP32 pin GPIO26
button_3 = Button(27) # Initialize buttons connected to ESP32 pin GPIO27
button_4 = Button(14) # Initialize buttons connected to ESP32 pin GPIO14
button_1.set_debounce_time(100) # Set debounce time to 100 milliseconds
button_2.set_debounce_time(100) # Set debounce time to 100 milliseconds
button_3.set_debounce_time(100) # Set debounce time to 100 milliseconds
button_4.set_debounce_time(100) # Set debounce time to 100 milliseconds
while True:
button_1.loop()
button_2.loop()
button_3.loop()
button_4.loop()
if button_1.is_pressed():
print("The button 1 is pressed")
if button_1.is_released():
print("The button 1 is released")
if button_2.is_pressed():
print("The button 2 is pressed")
if button_2.is_released():
print("The button 2 is released")
if button_3.is_pressed():
print("The button 3 is pressed")
if button_3.is_released():
print("The button 3 is released")
if button_4.is_pressed():
print("The button 4 is pressed")
if button_4.is_released():
print("The button 4 is released")