为什么 X 不能用作函数？

如何解决为什么 X 不能用作函数？

抱歉代码库混乱。我是 C++ 新手。

我正在尝试将循环和函数联系在一起。 (1) 湿度传感器和 (2) 伺服器，用于根据湿度打开和关闭控制杆。

我收到一个错误，提示“伺服”不能用作函数。我尝试将伺服更改为其他名称。我没有在其他任何地方使用伺服，例如变量，所以这似乎不是问题。

有没有人有其他建议？

#include "Servo.h"

Servo myservo;  // create servo object to control a servo

int pos = 0; // servo position variable
#define SensorPin A0 
float sensorValue = 0; 
bool Lever = 0; // soil moisture sensor variable; 0 = dry; 1 = wet;
bool pump = 0; // pump is set to 0,which = off

// servo function
void servo(bool);

void setup() {
  Serial.begin(9600); // soil moisture sensor setup
  myservo.attach(9); // servo setup
}

// soil moisture sensor loop
void loop() { 
  for (int i = 0; i <= 100; i++) { 
    sensorValue = sensorValue + analogRead(SensorPin); 
    delay(20);
  } 
  sensorValue = sensorValue/100.0; 
  Serial.print("Moisture level: ");
  Serial.print(sensorValue);
  Serial.print(";");
  
  if(sensorValue > 1000) {
    Lever = 0; // dry
  }

  if(sensorValue < 1000) {
    Lever = 1; // wet
  }

  switchOnOff(Lever);
  
  delay(1000);
}

// define the servo function
void switchOnOff(bool Lever) {
  Serial.print(" Lever: ");
  Serial.print(Lever);
  Serial.print(";");

  Serial.print(" Pump: ");
  Serial.print(pump);
  Serial.println(";");
  
  if(Lever == 0 && pump == 0) { // it is dry and pump is off,pump needs to be turned on
    for (pos = 90; pos <= 180; pos++) { // goes from 0 degrees to 90 degrees
      // in steps of 1 degree
      myservo.write(pos);             // tell servo to go to position in variable 'pos'
      delay(15);
    }
    delay(4000);
    for (pos = 180; pos >= 90; pos--) { // goes from 90 degrees to 0 degrees
      // in steps of 1 degree
      myservo.write(pos);             // tell servo to go to position in variable 'pos'
      delay(15);
    }
    pump = 1; // noting that pump is on
  }

  if(Lever == 0 && pump == 1) { // it is dry and pump is on
    return; // do nothing,return
  }

  if(Lever == 1 && pump == 1) { // it is wet and pump is on,pump needs to be turned off
    for (pos = 90; pos <= 180; pos++) { // goes from 90 degrees to 0 degrees
      // in steps of 1 degree
      myservo.write(pos);             // tell servo to go to position in variable 'pos'
      delay(15);
    }
    delay(4000);
    for (pos = 180; pos >= 90; pos--) { // goes from 0 degrees to 90 degrees
      // in steps of 1 degree
      myservo.write(pos);             // tell servo to go to position in variable 'pos'
      delay(15);
    }
    pump = 0; // noting that pump is off
  }

  if(Lever == 1 && pump == 0) { // it is wet and pump is off
    return; // do nothing,return
  }
}

谢谢。

解决方法

问题在于您在正确声明之前尝试使用 servo() 函数。首先，您需要先声明一个函数，然后才能在代码中提及它。其次，您对 servo() 的定义不正确。 int servo(lever)，其中 lever 不是类型。您应该查看以下内容：int servo(bool lever);，其中 lever 是 bool 函数采用的 servo() 类型参数。

然后，您的函数不会返回任何内容，它只有一些“副作用”，例如 myservo.write(pos);。所以，它应该是 void。

尝试以下安排：

#include "Servo.h"

Servo myservo;  // create servo object to control a servo
// twelve servo objects can be created on most boards

// Declare the function
void servo(bool);

int pos = 0;    // variable to store the servo position
#define SensorPin A0 
float sensorValue = 0; 
bool lever = 0; // lever is global variable of type bool


void setup() {
  myservo.attach(9);  // attaches the servo on pin 9 to the servo object    
  Serial.begin(9600); 
}


void loop() { 
  for (int i = 0; i <= 100; i++) { 
    sensorValue = sensorValue + analogRead(SensorPin); 
    delay(1); 
  } 
  sensorValue = sensorValue/100.0; 
  Serial.println(sensorValue); 
  delay(30);
  
  if(analogRead(0 > 100)) {
    lever = 1;
  }

  if(analogRead(0 < 100)) {
    lever = 0;
  }

  servo(lever);
}


// Define the function
void servo(bool lever) {
  if(lever == 1) { // On
    for (pos = 0; pos <= 180; pos += 1) { // goes from 0 degrees to 180 degrees
      // in steps of 1 degree
      myservo.write(pos);              // tell servo to go to position in variable 'pos'
    }
  }
  if(lever == 0) { // Off
    for (pos = 180; pos >= 0; pos -= 1) { // goes from 180 degrees to 0 degrees
      myservo.write(pos);              // tell servo to go to position in variable 'pos'
    } 
  }
}

附言setup() 在这里和那里重新定义也很混乱。