树莓派HC-SR501人体红外感应

HC-SR501数据输入线接入GPIO.1上，java代码如下：

/*  * #%L  * **********************************************************************  * ORGANIZATION  :  Pi4J  * PROJECT       :  Pi4J :: Java Examples  * FILENAME      :  GpioInputExample.java  *  * This file is part of the Pi4J project. More information about  * this project can be found here:  https://pi4j.com/  * **********************************************************************  * %%  * Copyright (C) 2012 - 2022 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.platform.PlatformAlreadyAssignedException; import com.pi4j.util.CommandArgumentParser; import com.pi4j.util.Console; import com.pi4j.util.ConsoleColor;  /**  * This example code demonstrates how to perform simple GPIO  * 这个示例代码演示了如何读取树莓派引脚  * pin state reading on the Raspberry Pi.  *  * @author Robert Savage  */ public class GpioInputExample {      /**      * [ARGUMENT/OPTION "--pin (#)" | "-p (#)" ]      * This example program accepts an optional argument for specifying the GPIO pin (by number)      * to use with this GPIO listener example. If no argument is provided, then GPIO #1 will be used.      * -- EXAMPLE: "--pin 4" or "-p 0".      *      * [ARGUMENT/OPTION "--pull (up|down|off)" | "-l (up|down|off)" | "--up" | "--down" ]      * This example program accepts an optional argument for specifying pin pull resistance.      * Supported values: "up|down" (or simply "1|0").   If no value is specified in the command      * argument, then the pin pull resistance will be set to PULL_UP by default.      * -- EXAMPLES: "--pull up", "-pull down", "--pull off", "--up", "--down", "-pull 0", "--pull 1", "-l up", "-l down".      *      * @param args      * @throws InterruptedException      * @throws PlatformAlreadyAssignedException      */     public static void main(String[] args) throws InterruptedException, PlatformAlreadyAssignedException {          // 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 Input Example");          // allow for user to exit program using CTRL-C         console.promptForExit();          // create gpio controller         final GpioController gpio = GpioFactory.getInstance();          // by default we will use gpio pin #01; however, if an argument         // has been provided, then lookup the pin by address         Pin pin = CommandArgumentParser.getPin(                 RaspiPin.class,    // pin provider class to obtain pin instance from                 RaspiPin.GPIO_01,  // default pin if no pin argument found                 args);             // argument array to search in          // by default we will use gpio pin PULL-UP; however, if an argument         // has been provided, then use the specified pull resistance         PinPullResistance pull = CommandArgumentParser.getPinPullResistance(                 PinPullResistance.PULL_UP,  // default pin pull resistance if no pull argument found                 args);                      // argument array to search in          // provision gpio pin as an input pin         final GpioPinDigitalInput input = gpio.provisionDigitalInputPin(pin, "MyInput", pull);          // set shutdown state for this pin: unexport the pin         input.setShutdownOptions(true);     Pin pinOut = CommandArgumentParser.getPin(     RaspiPin.class,    // pin provider class to obtain pin instance from     RaspiPin.GPIO_04,  // default pin if no pin argument found     args);             // argument array to search in    // provision gpio pin as an output pin and turn on   final GpioPinDigitalOutput output = gpio.provisionDigitalOutputPin(pinOut, "My Output", PinState.HIGH);    // set shutdown state for this pin: keep as output pin, set to low state   output.setShutdownOptions(false, PinState.LOW);       // prompt user that we are ready         console.println("Successfully provisioned ["   pin   "] with PULL resistance = ["   pull   "]");         console.emptyLine();         console.box("The GPIO input pin states will be dsplayed below.");
        console.emptyLine();
		for (int i = 0; i <10000 ; i++) {
        // display pin state
			console.emptyLine();
			console.println(" [" + input.toString() + "] digital state is: " + ConsoleColor.conditional(
					input.getState().isHigh(), // conditional expression
					ConsoleColor.GREEN,        // positive conditional color
					ConsoleColor.RED,          // negative conditional color
					input.getState()));
			console.emptyLine();
			if (input.getState().isHigh()) {
				output.setState(PinState.HIGH);
			}else{
				output.setState(PinState.LOW);
			}
			Thread.sleep(1000);
		}
        // 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();
    }
}

感应到信号后输出绿色字体

 在GPIO.4上接入继电器输入信号：

这样人体靠近的时候就接通继电器。

继电器上再接上电机，这样人体靠近后，就驱动电机转了起来。