Pallavi Prasad
Beep using PWM and speaker
Dependents: Hangman Weather_Station Ultrasonic Ultrasonicdistancesensor ... more
beep.cpp@0:080ef5594cce, 2012-10-11 (annotated)
- Committer:
- pprasad7
- Date:
- Thu Oct 11 20:14:49 2012 +0000
- Revision:
- 0:080ef5594cce
beep;
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| pprasad7 | 0:080ef5594cce | 1 | #include "beep.h" |
| pprasad7 | 0:080ef5594cce | 2 | #include "mbed.h" |
| pprasad7 | 0:080ef5594cce | 3 | |
| pprasad7 | 0:080ef5594cce | 4 | /** class to make sound with a buzzer, based on a PwmOut |
| pprasad7 | 0:080ef5594cce | 5 | * The class use a timeout to switch off the sound - it is not blocking while making noise |
| pprasad7 | 0:080ef5594cce | 6 | * |
| pprasad7 | 0:080ef5594cce | 7 | * Example: |
| pprasad7 | 0:080ef5594cce | 8 | * @code |
| pprasad7 | 0:080ef5594cce | 9 | * // Beep with 1Khz for 0.5 seconds |
| pprasad7 | 0:080ef5594cce | 10 | * #include "mbed.h" |
| pprasad7 | 0:080ef5594cce | 11 | * #include "beep.h" |
| pprasad7 | 0:080ef5594cce | 12 | * |
| pprasad7 | 0:080ef5594cce | 13 | * Beep buzzer(p21); |
| pprasad7 | 0:080ef5594cce | 14 | * |
| pprasad7 | 0:080ef5594cce | 15 | * int main() { |
| pprasad7 | 0:080ef5594cce | 16 | * ... |
| pprasad7 | 0:080ef5594cce | 17 | * buzzer.beep(1000,0.5); |
| pprasad7 | 0:080ef5594cce | 18 | * ... |
| pprasad7 | 0:080ef5594cce | 19 | * } |
| pprasad7 | 0:080ef5594cce | 20 | * @endcode |
| pprasad7 | 0:080ef5594cce | 21 | */ |
| pprasad7 | 0:080ef5594cce | 22 | |
| pprasad7 | 0:080ef5594cce | 23 | using namespace mbed; |
| pprasad7 | 0:080ef5594cce | 24 | // constructor |
| pprasad7 | 0:080ef5594cce | 25 | /** Create a Beep object connected to the specified PwmOut pin |
| pprasad7 | 0:080ef5594cce | 26 | * |
| pprasad7 | 0:080ef5594cce | 27 | * @param pin PwmOut pin to connect to |
| pprasad7 | 0:080ef5594cce | 28 | */ |
| pprasad7 | 0:080ef5594cce | 29 | |
| pprasad7 | 0:080ef5594cce | 30 | Beep::Beep(PinName pin) : _pwm(pin) { |
| pprasad7 | 0:080ef5594cce | 31 | _pwm.write(0.0); // after creating it have to be off |
| pprasad7 | 0:080ef5594cce | 32 | } |
| pprasad7 | 0:080ef5594cce | 33 | |
| pprasad7 | 0:080ef5594cce | 34 | /** stop the beep instantaneous |
| pprasad7 | 0:080ef5594cce | 35 | * usually not used |
| pprasad7 | 0:080ef5594cce | 36 | */ |
| pprasad7 | 0:080ef5594cce | 37 | void Beep::nobeep() { |
| pprasad7 | 0:080ef5594cce | 38 | _pwm.write(0.0); |
| pprasad7 | 0:080ef5594cce | 39 | } |
| pprasad7 | 0:080ef5594cce | 40 | |
| pprasad7 | 0:080ef5594cce | 41 | /** Beep with given frequency and duration. |
| pprasad7 | 0:080ef5594cce | 42 | * |
| pprasad7 | 0:080ef5594cce | 43 | * @param frequency - the frequency of the tone in Hz |
| pprasad7 | 0:080ef5594cce | 44 | * @param time - the duration of the tone in seconds |
| pprasad7 | 0:080ef5594cce | 45 | */ |
| pprasad7 | 0:080ef5594cce | 46 | |
| pprasad7 | 0:080ef5594cce | 47 | void Beep::beep(float freq, float time) { |
| pprasad7 | 0:080ef5594cce | 48 | |
| pprasad7 | 0:080ef5594cce | 49 | _pwm.period(1.0/freq); |
| pprasad7 | 0:080ef5594cce | 50 | _pwm.write(0.5); // 50% duty cycle - beep on |
| pprasad7 | 0:080ef5594cce | 51 | toff.attach(this,&Beep::nobeep, time); // time to off |
| pprasad7 | 0:080ef5594cce | 52 | } |
| pprasad7 | 0:080ef5594cce | 53 | |
| pprasad7 | 0:080ef5594cce | 54 | |
| pprasad7 | 0:080ef5594cce | 55 | |
| pprasad7 | 0:080ef5594cce | 56 |