Arduino MicroPython Button Module
Your Arduino Giga R1 WiFi can do a lot on its own, but sometimes a person has to tell it something: "a player buzzed in", "save a reading now", "pause the logger". One press on a button module is the simplest way to send that message. In this MicroPython guide, you will find out:
- What is inside the button module, and why it is safer to feed it 3.3V on the Giga.
- How to hook up its VCC, OUT and GND pins to the Arduino Giga with three jumper wires.
- How to print the raw value of the OUT pin in the Thonny Shell.
- How to turn every press into one "pressed" message and one "released" message, using a short sleep_ms() wait.
- How to get the same result with the DIYables-MicroPython-Button library, which never pauses your loop.
https://newbiely.com/images/cover/arduino-button-module-micropython.jpg
Hardware Preparation
Or you can buy the following kits:
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Additionally, some of these links are for products from our own brand, DIYables .
Overview of Button Module and Pinout
In short, the button module is a push button that brings its own resistor. A small tactile key with a colored cap sits on a little PCB, together with a pull-down resistor that holds the output at 0 while nobody touches it. The key is momentary: it is "on" only while your finger stays on it. DIYables sells the modules in a pack of five, one each in red, yellow, green, blue and white, which is handy when each key needs its own job.
A 3-pin 2.54mm header comes out of the board. Read the labels from one end to the other:
- VCC pin: the supply pin. The module accepts 3.3V to 5V DC, but on the Arduino Giga it goes to 3.3V.
- OUT pin: the signal pin. Wire it to any digital pin of the Arduino. We use D2.
- GND pin: wire it to a GND pin of the Arduino.
What MicroPython sees on OUT:
- Key not touched: the resistor pulls OUT down, so value() returns 0.
- Key held down: OUT is joined to VCC, so value() returns 1.
So the logic is "1 = pressed", the natural way round. You do not need Pin.PULL_UP here. In fact, turning on the internal pull-up would work against the resistor on the module.
※ NOTE THAT:
When the key is down, the OUT pin carries the same voltage you put on VCC. The I/O pins of the Giga R1 WiFi are 3.3V pins. If VCC were tied to 5V, every press would push 5V into pin D2, which can damage the board. Keep VCC on 3.3V.
One more thing about mechanical keys: the metal contacts bounce for a few milliseconds when they close or open. To a fast board, one push can look like several quick pushes. Examples 2 and 3 below show two ways to fix that.
Wiring Diagram
Three jumper wires are all you need, no breadboard. Pin D2 is the same pin the other button tutorials in this series use, so you can reuse their code later.
This image is created using Fritzing. Click to enlarge image
| Button Module | Arduino Giga R1 WiFi |
|---|---|
| VCC | 3.3V (do not use 5V) |
| OUT | D2 |
| GND | GND |
Arduino MicroPython Code - Press and Release Events With Delay Debounce
Most projects do not care about the level itself. They want to act once at the moment the key goes down, or once when it comes up. This script remembers the last state. When a new reading is different, it waits 50 ms for the bounce to die out, reads again, and prints a message only if the change is still there.
Detailed Instructions
- The wiring stays the same.
- Paste the new code into Thonny and save it to the Arduino as main.py, over the old file.
- Press Run (F5).
- Give the key three short taps.
Three taps, three pairs of lines. There are no extra "pressed" lines from bouncing. The only cost is that time.sleep_ms(50) stops the whole loop while it waits, so nothing else can run during those 50 ms.
Arduino MicroPython Code - Button Module With the DIYables Library
The third way hands the debounce job to the DIYables-MicroPython-Button library. It keeps track of time on its own, so button.loop() returns at once and the rest of your loop never gets stuck. You call is_pressed() and is_released() for the events, and get_state() for the steady level after debouncing.
Detailed Instructions
- In Thonny IDE, open Tools Manage packages.
- Type “DIYables-MicroPython-Button” in the search box and find the Button library created by DIYables.
- Click DIYables-MicroPython-Button, then click the Install button.
- Paste the code above into the editor and save it to the Arduino as main.py.
- Click Run (F5).
- Press the key, hold it a moment, and let go. Do it twice.
Each event shows up exactly once, and the steady state agrees with it. If you want the board to react even less to very short touches, raise the number in set_debounce_time(), for example to 100.
※ NOTE THAT:
If you see "pressed" when you let go and "released" when you push, the library is in pull-up mode. Check that you passed Pin.PULL_DOWN as the second argument.