Скачать или смотреть How to Detect a GPIOZero Button Press from a Function in Python

Discover how to handle GPIOZero Button presses while executing other functions in Python on the Raspberry Pi. Easy-to-understand solutions included!
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This video is based on the question https://stackoverflow.com/q/63864895/ asked by the user 'Tim Duncklee' ( https://stackoverflow.com/u/1163122/ ) and on the answer https://stackoverflow.com/a/63865526/ provided by the user 'NWiogrhkt' ( https://stackoverflow.com/u/13801894/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Detect a GPIOZero Button Press from a Function in Python

If you are working with Raspberry Pi and using the GPIOZero library to control buttons and other hardware, you might encounter a challenge when you want to handle multiple button presses at the same time. This guide will help you understand how to detect a button press while another function triggered by a different button is still running.

The Problem: Managing Multiple Button Presses

Imagine you have a setup where:

Button 1 triggers a function (first_button) that performs a task, like activating a relay.

Button 2 should also be able to trigger its own function (second_button) even while the first_button function is still running.

In your initial code, you face the issue that once the first_button function is executed, it runs indefinitely in a while True loop, making it impossible for second_button to respond.

Example of the Problematic Code

Here’s a simplified version of your initial code:

[[See Video to Reveal this Text or Code Snippet]]

The Solution: Utilizing Threads

To resolve this issue, you can use multi-threading. By allowing the first_button function to run in its own thread, you make it possible for the second_button function to run independently whenever pressed.

Step-by-Step Implementation

Setup the Environment: Import necessary libraries.

Define Global Variables: Use a variable to control the loop in do_stuff.

Create Worker Functions: Define what happens when each button is pressed outside the blocking loop.

Here’s how you can achieve that:

Example Code

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the Code

Threading: We import the _thread module and start a new thread for the do_stuff function inside the first_button function.

Global Variable: The run variable is used to control whether the do_stuff function should continue running or halt.

Button Press Handling: Each button press triggers a specific function that starts or stops the do_stuff loop, allowing for simultaneous operations.

Conclusion

With this implementation, you can efficiently handle multiple button presses without blocking each other. By utilizing threads, your Raspberry Pi can respond to different buttons seamlessly, making your projects much more interactive and responsive.

This technique is a great starting point for more complex GPIO operations, so explore and have fun experimenting with your Raspberry Pi projects!