The following example demonstrates the simple control of a GPIO pin on the Raspberry Pi.
Source Code
The source code for this example is included in the github repository:
https://github.com/Pi4J/pi4j/tree/master/pi4j-example/src/main/java/ControlGpioExample.java
/* * #%L * ********************************************************************** * ORGANIZATION : Pi4J * PROJECT : Pi4J :: Java Examples * FILENAME : ControlGpioExample.java * * This file is part of the Pi4J project. More information about * this project can be found here: http://www.pi4j.com/ * ********************************************************************** * %% * Copyright (C) 2012 - 2015 Pi4J * %% * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Lesser Public License for more details. * * You should have received a copy of the GNU General Lesser Public * License along with this program. If not, see * <http://www.gnu.org/licenses/lgpl-3.0.html>. * #L% */ import com.pi4j.io.gpio.GpioController; import com.pi4j.io.gpio.GpioFactory; import com.pi4j.io.gpio.GpioPinDigitalOutput; import com.pi4j.io.gpio.PinState; import com.pi4j.io.gpio.RaspiPin; /** * This example code demonstrates how to perform simple state * control of a GPIO pin on the Raspberry Pi. * * @author Robert Savage */ public class ControlGpioExample { public static void main(String[] args) throws InterruptedException { System.out.println("<--Pi4J--> GPIO Control Example ... started."); // create gpio controller final GpioController gpio = GpioFactory.getInstance();
// provision gpio pin #01 as an output pin and turn on final GpioPinDigitalOutput pin = gpio.provisionDigitalOutputPin(RaspiPin.GPIO_01, "MyLED", PinState.HIGH); // set shutdown state for this pin pin.setShutdownOptions(true, PinState.LOW); System.out.println("--> GPIO state should be: ON"); Thread.sleep(5000); // turn off gpio pin #01 pin.low(); System.out.println("--> GPIO state should be: OFF
"); Thread.sleep(5000); // toggle the current state of gpio pin #01 (should turn on) pin.toggle(); System.out.println("--> GPIO state should be: ON"); Thread.sleep(5000);
// toggle the current state of gpio pin #01 (should turn off) pin.toggle();
System.out.println("--> GPIO state should be: OFF"); Thread.sleep(5000); // turn on gpio pin #01 for 1 second and then off System.out.println("--> GPIO state should be: ON for only 1 second"); pin.pulse(1000, true); // set second argument to 'true' use a blocking call // stop all GPIO activity/threads by shutting down the GPIO controller // (this method will forcefully shutdown all GPIO monitoring threads and scheduled tasks) gpio.shutdown();
} }
JavaDoc
The following JavaDoc links are the primary interfaces used to control the Pi’s GPIO state:
Wiring Diagram
The following circuit can be used in conjunction with this sample code.
Read more: Simple GPIO Control using Pi4J