buzzer.cpp

00001 #include "buzzer.h"
00002 #include "mbed.h"
00003  
00004 /** class to make sound with a buzzer, based on a PwmOut
00005  *   The class use a timeout to switch off the sound  - it is not blocking while making noise
00006  *
00007  * Example:
00008  * @code
00009  * // Beep with 1Khz for 0.5 seconds
00010  * #include "mbed.h"
00011  * #include "beep.h"
00012  * 
00013  * Beep buzzer(PTC2);
00014  * 
00015  * int main() {
00016  *       ...
00017  *   buzzer.beep(1000,0.5);    
00018  *       ...
00019  * }
00020  * @endcode
00021  */
00022  
00023 using namespace mbed;
00024  // constructor
00025  /** Create a Beep object connected to the specified PwmOut pin
00026   *
00027   * @param pin PwmOut pin to connect to 
00028   */
00029     
00030 Beep::Beep(PinName pin) : _pwm(pin) {
00031     _pwm.write(0.0);     // after creating it have to be off
00032 }
00033  
00034  /** stop the beep instantaneous 
00035   * usually not used 
00036   */
00037 void Beep::nobeep() {
00038     _pwm.write(0.0);
00039 }
00040  
00041 /** Beep with given frequency and duration.
00042  *
00043  * @param frequency - the frequency of the tone in Hz
00044  * @param time - the duration of the tone in seconds
00045  */
00046      
00047 void Beep::beep(float freq, float time) {
00048  
00049     _pwm.period(1.0/freq);
00050     _pwm.write(0.5);            // 50% duty cycle - beep on
00051     toff.attach(this,&Beep::nobeep, time);   // time to off
00052 }