压电发声装置 piezo sound boards

什么是压电片?

压电晶体在变形或弯曲时,会产生电压。它们通常被制成非常薄的压电陶瓷圆片,并粘在薄的黄铜或合金金属圆片上。中间的圆片带正电,黄铜片带负电。当有它们间有电压产生时,我们可以检测到电压的变化并将其放大,从而产生声音。

反向操作也是可行的。如果将放大的信号传输给压电晶体,同样会产生音调。它能够再现复杂的声音,但频率范围有限。

接触式麦克风(也叫压电麦克风)由一个小而扁平的压电片/元件构成。它能够将物体表面的震动转化成电压。压电片是一种中间有一层晶体的薄黄铜圆片。当物体的表面有振动时,圆片会轻微弯曲,从而产生细微的电信号。

将压电片用作麦克风

接触式麦克风通常用于放大原声吉他、钢琴和其他发声乐器。它们能够发出非常高的阻抗信号,这是前置放大器(例如radial或者red-eye)作用的结果。同样,你也可以通过自己制作前置放大器来缩减成本。

除了放大乐器效果外,接触式麦克风还经常用于制作电影和视频的拟声音效。这里有几个将压电片用作麦克风的例子…


使用接触式麦克风录制各种声音,并配上背景音乐 🤔

接触式麦克风的室外实验

将接触式麦克风用作传感器

接触式麦克风也可用作传感器,向计算机或单片机发送数据,用来控制媒体或触发特定条件。要将接触式麦克风连接到单片机(如Ardiuno),我们需要将麦克风的正极与5V引脚连接,将负极与模拟输入引脚A0连接,并用一个10k的电阻将它的负极和地线相连,连接方式如下图所示。

/*
  Analog Input
 Demonstrates analog input by reading an analog sensor on analog pin 0 and
 turning on and off a light emitting diode(LED)  connected to digital pin 13. 
 The amount of time the LED will be on and off depends on
 the value obtained by analogRead(). 
 
 The circuit:
 * Potentiometer attached to analog input 0
 * center pin of the potentiometer to the analog pin
 * one side pin (either one) to ground
 * the other side pin to +5V
 * LED anode (long leg) attached to digital output 13
 * LED cathode (short leg) attached to ground
 
 * Note: because most Arduinos have a built-in LED attached 
 to pin 13 on the board, the LED is optional.
 
 
 Created by David Cuartielles
 modified 30 Aug 2011
 By Tom Igoe
 
 This example code is in the public domain.
 
 http://arduino.cc/en/Tutorial/AnalogInput
 
 */

int sensorPin = A0;    // select the input pin for the potentiometer
int ledPin = 13;      // select the pin for the LED
  // Pin 13: Arduino has an LED connected on pin 13
  // Pin 11: Teensy 2.0 has the LED on pin 11
  // Pin  6: Teensy++ 2.0 has the LED on pin 6
  // Pin 13: Teensy 3.0 has the LED on pin 13
int sensorValue = 0;  // variable to store the value coming from the sensor

void setup() {
  // declare the ledPin as an OUTPUT:
  pinMode(ledPin, OUTPUT);  
}

void loop() {
  // read the value from the sensor:
  sensorValue = analogRead(sensorPin);    
  // turn the ledPin on
  digitalWrite(ledPin, HIGH);  
  // stop the program for <sensorValue> milliseconds:
  delay(sensorValue);          
  // turn the ledPin off:        
  digitalWrite(ledPin, LOW);   
  // stop the program for for <sensorValue> milliseconds:
  delay(sensorValue);                  
}

使用压电片制作低保真音响

接触式麦克风的应用


拓展资料