Arduino示例代码讲解：Knock Sensor 敲击感知器

Knock Sensor 敲击感知器

这段代码是一个Arduino示例程序，用于检测敲击声。它通过读取一个压电元件（piezo element）的模拟输入值，并将其与一个设定的阈值进行比较。如果读取的值超过阈值，它会在串行端口输出“knock”，并切换引脚13上的LED的状态。这种方法适用于需要检测敲击或其他声音信号的场景。

/* Knock Sensor

   This sketch reads a piezo element to detect a knocking sound.
   It reads an analog pin and compares the result to a set threshold.
   If the result is greater than the threshold, it writes
   "knock" to the serial port, and toggles the LED on pin 13.

   The circuit:
	* + connection of the piezo attached to analog in 0
	* - connection of the piezo attached to ground
	* 1-megohm resistor attached from analog in 0 to ground

   http://www.arduino.cc/en/Tutorial/Knock

   created 25 Mar 2007
   by David Cuartielles <http://www.0j0.org>
   modified 30 Aug 2011
   by Tom Igoe

   This example code is in the public domain.

 */


// these constants won't change:
const int ledPin = 13;      // led connected to digital pin 13
const int knockSensor = A0; // the piezo is connected to analog pin 0
const int threshold = 100;  // threshold value to decide when the detected sound is a knock or not


// these variables will change:
int sensorReading = 0;      // variable to store the value read from the sensor pin
int ledState = LOW;         // variable used to store the last LED status, to toggle the light