digitalWrite (led, HIGH);

This code line sets the digital pin connected to the LED to a high voltage level, which turns on the LED.

Assuming that "led" is a variable representing the pin number connected to the LED, this line of code is used in Arduino programming to control the state of an LED connected to a digital pin.

"DigitalWrite" is an Arduino function used to write a value of either HIGH or LOW to a digital pin. HIGH means setting the pin to a voltage level of 5 volts, while LOW means setting the pin to a voltage level of 0 volts.

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帮我检查一下下面这个代码#include <NewPing.h> #include <Servo.h> #define TRIGGER_PIN 12 #define ECHO_PIN 11 #define MAX_DISTANCE 200 NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); int led1 = 2; int led2 = 3; int led3 = 4; int led4 = 5; Servo myservo; #define SIGNAL_PIN 6 void setup() { Serial.begin(9600); pinMode(led1, OUTPUT); pinMode(led2, OUTPUT); pinMode(led3, OUTPUT); pinMode(led4, OUTPUT); myservo.attach(10); pinMode(SIGNAL_PIN, INPUT); } void loop() { delay(50); unsigned int distance = sonar.ping_cm(); Serial.print("Distance: "); Serial.print(distance); Serial.println("cm"); if (distance >= 40) { digitalWrite(led1, LOW); digitalWrite(led2, LOW); digitalWrite(led3, LOW); digitalWrite(led4, LOW); } else if (distance >= 30) { digitalWrite(led1, HIGH); digitalWrite(led2, LOW); digitalWrite(led3, LOW); digitalWrite(led4, LOW); } else if (distance >= 20) { digitalWrite(led1, HIGH); digitalWrite(led2, HIGH); digitalWrite(led3, LOW); digitalWrite(led4, LOW); } else if (distance >= 10) { digitalWrite(led1, HIGH); digitalWrite(led2, HIGH); digitalWrite(led3, HIGH); digitalWrite(led4, LOW); } else { digitalWrite(led1, HIGH); digitalWrite(led2, HIGH); digitalWrite(led3, HIGH); digitalWrite(led4, HIGH); } if(digitalRead(SIGNAL_PIN) == HIGH) { Serial.println("Movement detected."); myservo.write(75); // 旋转90度 } else { Serial.println("Did not detect movement."); myservo.write(0); // 复位到0度 } delay(1000); }

代码看起来没有语法错误，但是如果你想进一步优化代码的话，可以考虑以下几点：

1. 在循环中使用delay会导致程序阻塞，建议使用非阻塞延迟函数，例如millis()函数。

2. 在处理距离数据时，可以考虑使用映射函数map()来将距离值映射到LED灯的亮度值。

3. 在处理运动检测信号时，可以考虑使用中断来实现，这样可以提高系统的响应速度。

4. 如果你的系统需要同时控制多个舵机，建议使用PCA9685芯片来实现多路PWM输出，这样可以减少Arduino的负担。

5. 在进行实际应用时，建议对系统进行更加全面的测试和验证，确保系统的稳定性和可靠性。

if (val==HIGH) { digitalWrite (led, HIGH); } else { digitalWrite (led, LOW); } }

This code is a simple if-else statement in Arduino programming. It checks if the value of the variable "val" is equal to "HIGH", and if it is, it sets the digital output pin "led" to "HIGH" (turns on the LED). If the value of "val" is not equal to "HIGH", it sets the digital output pin "led" to "LOW" (turns off the LED).