Ubuntu上用java控制LED灯

编程入门行业动态更新时间:2024-10-20 05:34:01

Ubuntu上用java控制LED灯

1、环境介绍

2、设备介绍

3、前期准备

3.1.给Ubuntu安装jdk

4、编写java代码

4.1.获取gpio引脚编号和路径

4.2.编写java代码

5、在Ubuntu系统上运行

6.在Ubuntu上使用终端直接控制LED ,操作如下:

1、环境介绍

JAVA

Intellij IDEA 2022.3.3 (Ultimate Edition)

jdk-1.8.0_77

Ubuntu

Linux version 5.10.110 (root@seven-HP-ZHAN-99-Pro-G1-MT) (aarch64-none-linux-gnu-gcc (GNU Toolchain for the A-profile Architecture 10.3-2021.07 (arm-10.29)) 10.3.1 20210621, GNU ld (GNU Toolchain for the A-profile Architecture 10.3-2021.07 (arm-10.29)) 2.36.1.20210621) #11 SMP Fri Feb 10 18:15:24 CST 2023

openjdk version "11.0.18" 2023-01-17
OpenJDK Runtime Environment (build 11.0.18+10-post-Ubuntu-0ubuntu120.04.1)
OpenJDK 64-Bit Server VM (build 11.0.18+10-post-Ubuntu-0ubuntu120.04.1, mixed mode)

2、设备介绍

3、前期准备

3.1.给Ubuntu安装jdk

代码如下（终端）：

armt@localhost:~$ apt-cache search java11openjdk-11-jdk - OpenJDK Development Kit (JDK)
openjdk-11-jdk-headless - OpenJDK Development Kit (JDK) (headless)
openjdk-11-jre - OpenJDK Java runtime, using Hotspot JIT
openjdk-11-jre-headless - OpenJDK Java runtime, using Hotspot JIT (headless)
default-jdk - Standard Java or Java compatible Development Kit
default-jdk-headless - Standard Java or Java compatible Development Kit (headless)

3.2选择要安装的jdk版本 , 然后输入y进行安装

armt@localhost:~$ sudo apt-get install openjdk-11-jdkReading package lists... Done
Building dependency tree       
Reading state information... Done
The following additional packages will be installed:openjdk-11-jdk-headless openjdk-11-jre openjdk-11-jre-headless
Suggested packages:openjdk-11-demo openjdk-11-source visualvm fonts-ipafont-gothicfonts-ipafont-mincho fonts-wqy-microhei | fonts-wqy-zenhei
The following NEW packages will be installed:openjdk-11-jdk openjdk-11-jdk-headless openjdk-11-jreopenjdk-11-jre-headless
0 upgraded, 4 newly installed, 0 to remove and 4 not upgraded.
Need to get 281 MB of archives.
After this operation, 435 MB of additional disk space will be used.
Do you want to continue? [Y/n] y

3.3 安装完成查看jdk是否安装成, 打印如下结果说明安装成功了

armt@localhost:~$ java -versionopenjdk version "11.0.18" 2023-01-17
OpenJDK Runtime Environment (build 11.0.18+10-post-Ubuntu-0ubuntu120.04.1)
OpenJDK 64-Bit Server VM (build 11.0.18+10-post-Ubuntu-0ubuntu120.04.1, mixed mode)

3.4 安装JDK时出现如下错误, 执行 sudo apt update

4、编写java代码

本案例采用GPIO的方式控制灯光亮灭,简单来说就是一个接口，通过变换状态值，来达到设备的变化。

4.1.获取gpio引脚编号和路径

图中GPIO4_C6 是属于 GPIO4属于第4组引脚, 1组有32个引脚, C6 的 C 组，如果是 A 组的话则为 0，B组为8, C 组为 16， D 组则为 24，以此递推 ,算出GPIO4_C6的引脚编号为4*32+16+6 =150

LED_W 表示白色灯引脚编号150
LED_G 表示绿色灯引脚编号149
LED_R 表示红色灯引脚编号122

RK芯片的路径:/sys/class/gpio/

新增其它GPIO口编号:

GPIO_1_A4 对应引脚编号: 36
GPIO_2_B0 对应引脚编号: 40
GPIO_3_B1 对应引脚编号: 41
GPIO_4_B2 对应引脚编号: 42

4.2.编写java代码

    private static final String GPIO_PATH = "/sys/class/gpio/";//路径private static final String GPIO_PIN_W = "150"; // 白灯引脚编号private static final String GPIO_PIN_G = "149"; // 绿灯引脚编号private static final String GPIO_PIN_R = "122"; // 红灯引脚编号//如果想控制其他IO口 记得替换引脚编号//private static final String GPIO1_A4 = "36";//private static final String GPIO1_B0 = "40"; //private static final String GPIO1_B1 = "41";//private static final String GPIO1_B2 = "42";

操作步骤:
1.导出GPIO引脚

    /*** 导出GPIO引脚*/private static void exportPin(String pin) {writeFile(GPIO_PATH + "export", pin);}

2.设置GPIO引脚为输出模式

 /*** 设置GPIO引脚为输出模式*/private static void setPinDirection(String pin, String direction) {writeFile(GPIO_PATH + "gpio" + pin + "/direction", direction);}

3.控制LED灯开/关

/*** 控制LED灯*/private static void setPinValue(String pin, String value) {writeFile(GPIO_PATH + "gpio" + pin + "/value", value);}

4.清理GPIO引脚

 /*** 清理GPIO引脚*/private static void unexportPin(String pin) {writeFile(GPIO_PATH + "unexport", pin);}

    private static void writeFile(String path, String value) {try (FileWriter fileWriter = new FileWriter(path)) {fileWriter.write(value);} catch (IOException e) {e.printStackTrace();}}

打开LED灯

  /*** 打开灯* @param pin 引脚编号*/private static void openLED(String pin){//打开前关闭所有led,避免多个灯同时点亮烧坏电路板closeLED(GPIO_PIN_W);closeLED(GPIO_PIN_G);closeLED(GPIO_PIN_R);// 导出GPIO引脚exportPin(pin);// 设置GPIO引脚为输出模式setPinDirection(pin, "out");// 控制LED灯setPinValue(pin, "1"); // 打开LED灯}

关闭LED灯

 /*** 关闭灯* @param pin 引脚编号*/private static void closeLED(String pin){// 控制LED灯setPinValue(pin, "0"); // 关闭LED灯// 清理GPIO引脚unexportPin(pin);}

完整代码:

package org.example;import javax.swing.*;
import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.FileWriter;
import java.io.IOException;public class Main {private static final String GPIO_PATH = "/sys/class/gpio/";private static final String GPIO_PIN_W = "150"; // 白灯引脚编号private static final String GPIO_PIN_G = "149"; // 绿灯引脚编号private static final String GPIO_PIN_R = "122"; // 红灯引脚编号public static void main(String[] args) {createAndShowGUI();}/*** 打开灯* @param pin 引脚编号*/private static void openLED(String pin){//打开前关闭所有led,避免多个灯同时点亮烧坏电路板closeLED(GPIO_PIN_W);closeLED(GPIO_PIN_G);closeLED(GPIO_PIN_R);// 导出GPIO引脚exportPin(pin);// 设置GPIO引脚为输出模式setPinDirection(pin, "out");// 控制LED灯setPinValue(pin, "1"); // 打开LED灯}/*** 关闭灯* @param pin 引脚编号*/private static void closeLED(String pin){// 控制LED灯setPinValue(pin, "0"); // 关闭LED灯// 清理GPIO引脚unexportPin(pin);}/*** 导出GPIO引脚*/private static void exportPin(String pin) {writeFile(GPIO_PATH + "export", pin);}/*** 清理GPIO引脚*/private static void unexportPin(String pin) {writeFile(GPIO_PATH + "unexport", pin);}/*** 设置GPIO引脚为输出模式*/private static void setPinDirection(String pin, String direction) {writeFile(GPIO_PATH + "gpio" + pin + "/direction", direction);}/*** 控制LED灯*/private static void setPinValue(String pin, String value) {writeFile(GPIO_PATH + "gpio" + pin + "/value", value);}private static void writeFile(String path, String value) {try (FileWriter fileWriter = new FileWriter(path)) {fileWriter.write(value);} catch (IOException e) {e.printStackTrace();}}/*** 创建UI*/private static void createAndShowGUI() {JFrame.setDefaultLookAndFeelDecorated(true);JFrame frame = new JFrame("GPIO控制LED开关");frame.addWindowListener(new WindowAdapter() {@Overridepublic void windowClosing(WindowEvent e) {super.windowClosing(e);//窗口关闭时关闭LEDcloseLED(GPIO_PIN_W);closeLED(GPIO_PIN_G);closeLED(GPIO_PIN_R);}});//设置弹窗大小frame.setLocation(200, 200);JPanel panel = new JPanel();panel.setPreferredSize(new Dimension(600, 400));panel.setLayout(null);// 添加面板JButton wBtn = new JButton("打开-白灯");wBtn.addActionListener(e -> openLED(GPIO_PIN_W));wBtn.setBounds(60, 25, 130, 30);JButton gBtn = new JButton("打开-绿灯");gBtn.addActionListener(e -> openLED(GPIO_PIN_G));gBtn.setBounds(220, 25, 130, 30);JButton rBtn = new JButton("打开-红灯");rBtn.addActionListener(e -> openLED(GPIO_PIN_R));rBtn.setBounds(380, 25, 130, 30);// 关闭按钮JButton wBtnC = new JButton("关闭-白灯");wBtnC.addActionListener(e -> closeLED(GPIO_PIN_W));wBtnC.setBounds(60, 75, 130, 30);JButton gBtnC = new JButton("关闭-绿灯");gBtnC.addActionListener(e -> closeLED(GPIO_PIN_G));gBtnC.setBounds(220, 75, 130, 30);JButton rBtnC = new JButton("关闭-红灯");rBtnC.addActionListener(e -> closeLED(GPIO_PIN_R));rBtnC.setBounds(380, 75, 130, 30);panel.add(wBtn);panel.add(gBtn);panel.add(rBtn);panel.add(wBtnC);panel.add(gBtnC);panel.add(rBtnC);frame.add(panel);// 显示窗口frame.pack();frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);frame.setVisible(true);}
}