Source: https://mokxi.com/libraries/acebutton
Updated: 2026-11-11

Libraries / Input

Arduino library · Input

# AceButton: every button event through one handler

AceButton by Brian Park takes a different approach from the click-handler libraries. Instead of one function per action, every event from every button goes to a single handler, which is told which button, which event and the button’s state. A switch on the event type then decides what happens. This scales well: ten buttons still need only one handler.

Open the example in the editor See the calls

Built in on Mokxi: #include <AceButton.h> and it builds, with nothing to install. Free, and no account needed.

## What AceButton does

Pressed and released are always reported. The rest are switched on as features of the button’s ButtonConfig: kFeatureClick, kFeatureDoubleClick, kFeatureLongPress, kFeatureRepeatPress for auto-repeat while held, and kFeatureHeartBeat for a regular tick. The kFeatureSuppress flags hide the released event that follows a click or long press, so the handler is not told about the same press twice.

AceButton does not set the pin mode itself, so the sketch calls pinMode(pin, INPUT_PULLUP) first. The default timings are a 20 ms debounce, 200 ms for a click, 400 ms between the two presses of a double click and 1000 ms for a long press. Beyond plain pins, it can read a resistor ladder of buttons on one analog pin, or binary-encoded buttons, through other ButtonConfig classes.

Library Manager name | AceButton

Author | Brian T. Park

Include | #include <AceButton.h>
#include <ace_button/fast/ButtonConfigFast1.h>
#include <ace_button/fast/ButtonConfigFast2.h>
#include <ace_button/fast/ButtonConfigFast3.h>

Boards | every board Mokxi compiles for

In the simulator | Simulated: it runs against the part the way it does on the bench.

Parts it drives | Pushbutton

## Install it

It builds on every board Mokxi compiles for.

In Mokxi it is built in: #include <AceButton.h> and the sketch compiles, with no download, no zip and no Library Manager.

On a real board, install "AceButton" by Brian T. Park from the Arduino IDE’s Library Manager (Sketch, Include Library, Manage Libraries), or add AceButton to lib_deps in PlatformIO. Mokxi follows the calls of release 1.10.1, so a sketch written here builds there too.

- ESP32-C3
- Arduino Uno
- Arduino Nano
- Arduino Mega 2560
- Arduino Leonardo
- SparkFun Pro Micro
- Arduino Micro
- ESP32-C6
- WCH CH32V003
- ATtiny85
- Raspberry Pi Pico
- Raspberry Pi Pico W
- Seeed XIAO SAMD21
- STM32
- STM32 Nucleo-F411RE
- STM32 Blue Pill
- micro:bit V2
- Arduino Uno R4
- ESP32 DevKit
- ESP32-S3-DevKitC-1
- ESP8266 NodeMCU
- Arduino Pro Mini 3.3 V
- Seeed XIAO ESP32-C3
- ESP32-C3 SuperMini
- Seeed XIAO ESP32-C6
- ESP32-DevKitC V4
- LOLIN32 Lite
- Wemos D1 R32
- Cheap Yellow Display
- TTGO T-Display
- Seeed XIAO ESP32-S3
- Arduino Nano ESP32
- Arduino Nano RP2040 Connect
- Seeed XIAO RP2040
- Waveshare RP2040-Zero
- Arduino Uno R4 WiFi

## The calls you will use

In the order a sketch meets them.

### AceButton button(BUTTON_PIN)

A button on a pin that reads HIGH when released, the pull-up arrangement. A second argument of LOW is for pull-down wiring.

### pinMode(BUTTON_PIN, INPUT_PULLUP)

Turns the pull-up on. AceButton leaves the pin mode to the sketch, so this line is required.

### ButtonConfig *config = button.getButtonConfig()

The settings object the button uses. By default every button shares the one system config.

### config->setEventHandler(handleEvent)

Sets the handler for all buttons on this config: void handleEvent(AceButton *button, uint8_t eventType, uint8_t buttonState).

### config->setFeature(ButtonConfig::kFeatureLongPress)

Turns on an extra event. Call it once per feature: click, double click, long press, repeat press or heartbeat.

### config->setLongPressDelay(2000)

Changes how long a press must last to be a long press. setClickDelay() and setDoubleClickDelay() change the others.

### button.check()

Reads and debounces the pin and calls the handler for any event. Call it on every pass of loop(), every few milliseconds at least.

### case AceButton::kEventClicked:

The event names to switch on: kEventPressed, kEventReleased, kEventClicked, kEventDoubleClicked, kEventLongPressed and kEventRepeatPressed.

## Example: Button events with AceButton

On the Arduino Uno R3. It runs in the browser exactly as printed.

sketch.ino · Arduino Uno R3

### Wiring

- Arduino Uno R3 2 to Pushbutton 1a
- Arduino Uno R3 GND to Pushbutton 2a

Open it in the editor, wired and ready to run

## Common errors and how to fix them

### The handler gets pressed and released but never clicked

Click, double click and long press are off until switched on. Call config->setFeature(ButtonConfig::kFeatureClick) and the others you need in setup().

### A long press also triggers a released event that undoes it

Set ButtonConfig::kFeatureSuppressAfterLongPress, which hides the release after a long press (or reports it as kEventLongReleased), so the handler can treat the two cases apart.

### The button reads pressed as soon as the sketch starts

The pin is floating because the pull-up is off. Add pinMode(pin, INPUT_PULLUP) in setup() before the first check(); AceButton does not do it for you.

## Keep going

### Learn

- Arduino Button Debounce: See the Bounce, Then Fix It
- Arduino pinMode(): OUTPUT, INPUT and INPUT_PULLUP

### Parts

- Pushbutton

### More input libraries

- XPT2046_Touchscreen
- Keypad
- OneButton
- Encoder
- RotaryEncoder
- CapacitiveSensor
- IRremote
- Adafruit MCP23017 Arduino Library

Every built-in library · Open the editor

## Try AceButton without installing anything

Open the example, change the sketch, and keep your version in a free account.

Start building free

Open the editor