Arduino.通过tone()控制无源蜂鸣器输出音频震荡信号实现发声_幻河

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Arduino.通过tone()控制无源蜂鸣器输出音频震荡信号实现发声

(2015-09-29 15:41:56)

标签：

arduino

蜂鸣器

音频震荡信号

先来一段常见的Arduino代码

void buzzerVoice(){

unsigned char i,j;

for(i=0;i<200;i++){

digitalWrite(PIN_BUZZER,HIGH);

delay(1);

digitalWrite(PIN_BUZZER,LOW);

delay(1);

}

for(i=0;i<100;i++){

digitalWrite(PIN_BUZZER,HIGH);

delay(2);

digitalWrite(PIN_BUZZER,LOW);

delay(2);

}

能够发声, 但太不好听

要生产音频脉冲，只要算出某一音频的周期(1/频率)，可以利用定时器计时的方式得到此频率的脉冲

Arduino官方封装了一个方法tone(), 详细说明如下

tone()

Description

Generates a square wave of the specified frequency (and 50% duty cycle) on a pin. A duration can be specified, otherwise the wave continues until a call to noTone(). The pin can be connected to a piezo buzzer or other speaker to play tones.

Only one tone can be generated at a time. If a tone is already playing on a different pin, the call to tone() will have no effect. If the tone is playing on the same pin, the call will set its frequency.

Use of the tone() function will interfere with PWM output on pins 3 and 11 (on boards other than the Mega).

It is not possible to generate tones lower than 31Hz. For technical details, see Brett Hagman's notes.

NOTE: if you want to play different pitches on multiple pins, you need to call noTone() on one pin before calling tone() on the next pin.

Syntax

tone(pin, frequency)

tone(pin, frequency, duration)

Parameters

pin: the pin on which to generate the tone

frequency: the frequency of the tone in hertz - unsigned int

duration: the duration of the tone in milliseconds (optional) - unsigned long

Returns

nothing