Java Internet of Things Hardware Development Tutorial: Implementing Intelligent Traffic Light Control Function

Java Internet of Things Hardware Development Tutorial: Implementing Intelligent Traffic Light Control Function

Currently, Internet of Things technology has been widely used in all walks of life, among which intelligent transportation systems are A very important application area. In intelligent transportation systems, traffic light control is an essential function. This article will introduce how to use Java language to develop IoT hardware to realize the control function of intelligent traffic lights, and provide specific code examples.

1. Hardware preparation
Before starting development, we need to prepare the following hardware:

1. Arduino development board
2. Red, yellow and green LEDs Lamp
3. DuPont wire
4. Resistor (for current limiting)

2. Circuit connection
Connect the Arduino development board to the LED lamp through the DuPont wire. The specific connection method is as follows:

1. Connect the digital pins of Arduino (D2, D3, D4) to the positive poles of the red, yellow, and green LED lights respectively
2. Connect the LED lights The negative pole is connected to the GND port of Arduino through a resistor

3. Software development
Before starting software development, we need to install the following software:

1. Arduino IDE ( Used to write and upload programs to the Arduino development board)
2. Java development environment (IDE)
3. Arduino side code
   First, open the Arduino IDE and write the following code:

int redPin = 2; // 红灯引脚
int yellowPin = 3; // 黄灯引脚
int greenPin = 4; // 绿灯引脚

void setup() {
  pinMode(redPin, OUTPUT);
  pinMode(yellowPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
}

void loop() {
  // 设置红灯亮，黄灯熄灭，绿灯熄灭
  digitalWrite(redPin, HIGH);
  digitalWrite(yellowPin, LOW);
  digitalWrite(greenPin, LOW);
  delay(5000); // 等待5秒

  // 设置红灯熄灭，黄灯亮，绿灯熄灭
  digitalWrite(redPin, LOW);
  digitalWrite(yellowPin, HIGH);
  digitalWrite(greenPin, LOW);
  delay(2000); // 等待2秒

  // 设置红灯熄灭，黄灯熄灭，绿灯亮
  digitalWrite(redPin, LOW);
  digitalWrite(yellowPin, LOW);
  digitalWrite(greenPin, HIGH);
  delay(5000); // 等待5秒
}

After writing is completed, click the upload button on the Arduino IDE interface to upload the code to the Arduino development board.

2. Java side code
   Open the Java development environment, create a new Java project, and add the Arduino communication library (such as RXTXcomm), and then write the following code:

import java.io.OutputStream;
import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;

public class TrafficLightController {
    private static final String PORT_NAME = "COM3"; // 将COM3替换为你的串口号
    private static final int BAUD_RATE = 9600; // 设置波特率

    public static void main(String[] args) {
        try {
            CommPortIdentifier portIdentifier = CommPortIdentifier.getPortIdentifier(PORT_NAME);
            SerialPort serialPort = (SerialPort) portIdentifier.open("TrafficLightController", 2000);
            serialPort.setSerialPortParams(BAUD_RATE, SerialPort.DATABITS_8, SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);

            OutputStream outputStream = serialPort.getOutputStream();

            while (true) {
                // 设置红灯亮，黄灯熄灭，绿灯熄灭
                outputStream.write("red".getBytes());
                Thread.sleep(5000); // 等待5秒

                // 设置红灯熄灭，黄灯亮，绿灯熄灭
                outputStream.write("yellow".getBytes());
                Thread.sleep(2000); // 等待2秒

                // 设置红灯熄灭，黄灯熄灭，绿灯亮
                outputStream.write("green".getBytes());
                Thread.sleep(5000); // 等待5秒
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Among them, PORT_NAME needs to be modified according to your serial port number.

4. Testing and Operation
Connect the Arduino development board to the USB interface of the computer and make sure the serial number is correct. Then run the Arduino code and Java code respectively, and you will see that the traffic light control switches cyclically at predetermined time intervals.

5. Summary
Through the introduction of this article, we have learned how to use Java language to develop IoT hardware and realize the control function of intelligent traffic lights. This is of great significance for improving the efficiency and safety of the transportation system. I hope this article will be helpful to your learning and exploration in the field of Internet of Things.

The above is the detailed content of Java Internet of Things Hardware Development Tutorial: Implementing Intelligent Traffic Light Control Function. For more information, please follow other related articles on the PHP Chinese website!