Arduino MicroPython Button Debounce
When you connect a button to an Arduino, it may sometimes appear as if the button has been pressed multiple times, even though you only pressed it once. This happens because the button can rapidly switch between pressed and unpressed states, a phenomenon known as **bouncing** or **chattering**. Bouncing can create issues in your Arduino program.
This guide will teach you how to resolve this problem on the Arduino by using a technique called **debouncing** with MicroPython. Debouncing ensures that the Arduino interprets each button press as a single, distinct action.
We will go through the following steps:
- Writing Arduino MicroPython code without debouncing a button.
- Writing Arduino MicroPython code with debouncing for a single button.
- Writing Arduino 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 Arduino to breadboard-mount button
This image is created using Fritzing. Click to enlarge image
- How to connect Arduino to a panel-mounted button
This image is created using Fritzing. Click to enlarge image
Let's compare the Arduino MicroPython code without and with debouncing to see how debouncing affects the behavior.
Arduino - Button without Debounce
First, let's examine the MicroPython code for Arduino without debouncing to understand its behavior.
"""
This Arduino MicroPython script was developed by newbiely.com
This Arduino MicroPython script is made available for public use without any restriction
For comprehensive instructions and wiring diagrams, please visit:
https://newbiely.com/tutorials/arduino-micropython/arduino-micropython-button-debounce
"""
from machine import Pin
import time
BUTTON_PIN = 'D2' # The Arduino Giga WiFi pin D2 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 run the above MicroPython code on Arduino with Thonny IDE:
- Make sure Thonny IDE is installed on your computer.
- Make sure MicroPython firmware is installed on your Arduino board.
- If you are new to Arduino with MicroPython, see the Getting Started with Arduino and MicroPython.
- Connect the button to the Arduino as shown in the diagram.
- Connect the Arduino board to your computer with a USB cable.
- Open Thonny IDE and go to Tools Options.
- Under the Interpreter tab, select MicroPython (generic) from the dropdown menu.
- Select the COM port corresponding to your Arduino board (e.g., COM33 on Windows or /dev/ttyACM0 on Linux).
- Copy the provided Arduino MicroPython code and paste it into Thonny's editor.
- Save the MicroPython code to your Arduino by:
- Clicking the Save button or pressing Ctrl+S.
- In the save dialog, choose MicroPython device and name the file main.py.
- Click the green Run button (or press F5) to execute the code.
- 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 (generic) • Giga Virtual Comm Port in FS Mode @ COM33 ≡
As you can see in the log, you pressed the button only once, but the Arduino detected multiple presses.
Arduino Debounce for a Button
"""
This Arduino MicroPython script was developed by newbiely.com
This Arduino MicroPython script is made available for public use without any restriction
For comprehensive instructions and wiring diagrams, please visit:
https://newbiely.com/tutorials/arduino-micropython/arduino-micropython-button-debounce
"""
from DIYables_MicroPython_Button import Button
import time
# Initialize buttons connected to pins D2 of Arduino Giga WiFi
button = Button('D2')
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 Arduino 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 (generic) • Giga Virtual Comm Port in FS Mode @ COM33 ≡
You pressed the button once, and the Arduino 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.
Arduino Debounce for multiple Buttons
Let's add debouncing to five buttons using Arduino with MicroPython. Here's how to connect them to your Arduino:
This image is created using Fritzing. Click to enlarge image
"""
This Arduino MicroPython script was developed by newbiely.com
This Arduino MicroPython script is made available for public use without any restriction
For comprehensive instructions and wiring diagrams, please visit:
https://newbiely.com/tutorials/arduino-micropython/arduino-micropython-button-debounce
"""
from DIYables_MicroPython_Button import Button
import time
button_1 = Button('D2') # Initialize buttons connected to Arduino Giga WiFi pin D2
button_2 = Button('D3') # Initialize buttons connected to Arduino Giga WiFi pin D3
button_3 = Button('D4') # Initialize buttons connected to Arduino Giga WiFi pin D4
button_4 = Button('D5') # Initialize buttons connected to Arduino Giga WiFi pin D5
button_5 = Button('D6') # Initialize buttons connected to Arduino Giga WiFi pin D6
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
button_5.set_debounce_time(100) # Set debounce time to 100 milliseconds
while True:
button_1.loop()
button_2.loop()
button_3.loop()
button_4.loop()
button_5.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")
if button_5.is_pressed():
print("The button 5 is pressed")
if button_5.is_released():
print("The button 5 is released")