-example.1.4.source-code.BroadcomPinNumberingGpioListenerExample Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of pi4j-example Show documentation
Pi4J Java Examples using the Pi4J Library
The newest version!
/*
 * #%L
 * **********************************************************************
 * ORGANIZATION  :  Pi4J
 * PROJECT       :  Pi4J :: Java Examples
 * FILENAME      :  BroadcomPinNumberingGpioListenerExample.java
 *
 * This file is part of the Pi4J project. More information about
 * this project can be found here:  https://pi4j.com/
 * **********************************************************************
 * %%
 * Copyright (C) 2012 - 2021 Pi4J
 * %%
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * #L%
 */

import com.pi4j.io.gpio.*;
import com.pi4j.io.gpio.event.GpioPinDigitalStateChangeEvent;
import com.pi4j.io.gpio.event.GpioPinListenerDigital;
import com.pi4j.util.Console;
import com.pi4j.util.ConsoleColor;

/**
 * This example code demonstrates how to setup a listener
 * for GPIO pin state changes on the RaspberryPi
 * using the Broadcom chipset GPIO pin numbering scheme.
 *
 * @author Robert Savage
 */
public class BroadcomPinNumberingGpioListenerExample {

    public static void main(String[] args) throws InterruptedException {

        System.out.println("<--Pi4J--> GPIO Listener Example ... started.");

        // in order to use the Broadcom GPIO pin numbering scheme, we need to configure the
        // GPIO factory to use a custom configured Raspberry Pi GPIO provider
        GpioFactory.setDefaultProvider(new RaspiGpioProvider(RaspiPinNumberingScheme.BROADCOM_PIN_NUMBERING));

        // create Pi4J console wrapper/helper
        // (This is a utility class to abstract some of the boilerplate code)
        final Console console = new Console();

        // print program title/header
        console.title("<-- The Pi4J Project -->", "GPIO Listen Example");

        // allow for user to exit program using CTRL-C
        console.promptForExit();

        // create gpio controller
        final GpioController gpio = GpioFactory.getInstance();

        // provision broadcom gpio pin #13 as an input pin
        final GpioPinDigitalInput myButton = gpio.provisionDigitalInputPin(RaspiBcmPin.GPIO_13, "MyButton", PinPullResistance.PULL_DOWN);

        // unexport the GPIO pin when program exits
        myButton.setShutdownOptions(true);

        // prompt user that we are ready
        console.println(" ... Successfully provisioned [" + myButton.getPin() + "] with PULL resistance = [" + myButton.getPin() + "]");
        console.emptyLine();
        console.box("Please complete the [" + myButton.getPin() + "] circuit and see",
                "the listener feedback here in the console.");
        console.emptyLine();

        // create and register gpio pin listener
        myButton.addListener(new GpioPinListenerDigital() {
            @Override
            public void handleGpioPinDigitalStateChangeEvent(GpioPinDigitalStateChangeEvent event) {
                // display pin state on console
                console.println(" --> GPIO PIN STATE CHANGE: " + event.getPin() + " = " +
                        ConsoleColor.conditional(
                                event.getState().isHigh(), // conditional expression
                                ConsoleColor.GREEN,        // positive conditional color
                                ConsoleColor.RED,          // negative conditional color
                                event.getState()));        // text to display
            }

        });

        // wait (block) for user to exit program using CTRL-C
        console.waitForExit();

        // forcefully shutdown all GPIO monitoring threads and scheduled tasks
        gpio.shutdown();
    }
}