敲门项目的Arduino蜂鸣器不工作

Question

我正在尝试使用Arduino和压电蜂鸣器生成一个敲击检测器。此项目中使用的那个与此图片中使用的相同

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使用以下代码

const int outputPin = 8;    // led indicator connected to digital pin
const int knockSensor = A0; // the piezo is connected to an analog pin
const int thresholdHIGH =150;  // threshold value to decide when the detected knock is hard (HIGH)
const int thresholdLOW = 120;  // threshold value to decide when the detected knock is gentle (LOW)


const int secretKnockLength = 4; //How many knocks are in your secret knock

/* This is the secret knock sequence
 * 0 represents a LOW or quiet knock
 * 1 represents a HIGH or loud knock
 * The sequence can be as long as you like, but longer codes increase the difficulty of matching */
const int secretKnock[secretKnockLength] = {0, 0, 1, 0};

int secretCounter = 0; //this tracks the correct knocks and allows you to move through the sequence
int sensorReading = 0; // variable to store the value read from the sensor pin

void setup() {

  //Set the output pin as an OUTPUT
  pinMode(outputPin, OUTPUT);

  //analogWrite(knockSensor, LOW);  

  //Begin Serial Communication.
  Serial.begin(9600);

}

void loop() {

  // read the piezo sensor and store the value in the variable sensorReading:
  sensorReading = analogRead(knockSensor);
  Serial.print ("Valor del Sensor: ");
  Serial.println(sensorReading);

  // First determine is knock if Hard (HIGH) or Gentle (LOW)

  //Hard knock (HIGH) is detected
  if (sensorReading >= thresholdHIGH) {

    //Check to see if a Hard Knock matches the Secret Knock in the correct sequence.
    if (secretKnock[secretCounter] == 1) {

      //The Knock was correct, iterate the counter.
      secretCounter++;
      Serial.println("Correct");


    } else {

      //The Knock was incorrect, reset the counter
      secretCounter = 0;
      Serial.println("Fail");
      digitalWrite(outputPin, LOW);
    }//close if

    //Allow some time to pass before sampling again to ensure a clear signal.
    delay(100);

    //Gentle knock (LOW) is detected
  } else if (sensorReading >= thresholdLOW) {

    //Check to see if a Gentle Knock matches the Secret Knock in the correct sequence.
    if (secretKnock[secretCounter] == 0) {

      //The Knock was correct, iterate the counter.
      secretCounter++;
      Serial.println("Correct");

    } else {

      //The Knock was incorrect, reset the counter.
      secretCounter = 0;
      Serial.println("Fail");

    }//close if

    //Allow some time to pass before sampling again to ensure a clear signal.
    delay(100);

  }//close if else

  //Check for successful entry of the code, by seeing if the entire array has been walked through.
  if (secretCounter == (secretKnockLength) ) {

    Serial.println("Welcome");

    //if the sececret knock is correct, illuminate the LED for a couple seconds
    digitalWrite(outputPin, HIGH);


    //Reset the secret counter to 0.
    secretCounter = 0;

  }//close success check

}//close loop".

我的问题是蜂鸣器什么也没检测到。我不知道这是因为蜂鸣器不正确还是别的什么原因。

有什么想法吗？

Answer 1

如果问题是蜂鸣器没有发出任何噪音，那么您应该在代码中使用tone()函数。(https://www.arduino.cc/reference/en/language/functions/advanced-io/tone/)

您的代码编译成功，所以如果这不是您的问题，那么可能是您的项目的连接有问题。

Answer 2

要检测敲击，您需要使用不带驱动器电路的压电。根据Arduino tutorial所说，避免用塑料外壳压电。你应该使用像这样看起来像金属盘的压电陶瓷

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(图片来自sparkfun)

注:带塑料外壳的压电陶瓷可能含有驱动电路，也可能根本不含压电陶瓷(可能是磁性蜂鸣器)。