Peter Drescher
Make noise with a piezo buzzer. Use a pwm pin.
Dependents: Cave_Runner popcorn default USBMIDI_Buzzer ... more
beep.cpp@4:d8e14429a95f, 2012-09-11 (annotated)
- Committer:
- dreschpe
- Date:
- Tue Sep 11 08:21:45 2012 +0000
- Revision:
- 4:d8e14429a95f
- Parent:
- beep.c@3:5a8242af60ba
change beep.c to beep.cpp to avoid compiler problems
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| dreschpe | 0:18e4a9c978ec | 1 | #include "beep.h" |
| dreschpe | 0:18e4a9c978ec | 2 | #include "mbed.h" |
| dreschpe | 0:18e4a9c978ec | 3 | |
| dreschpe | 2:a34405c20cf5 | 4 | /** class to make sound with a buzzer, based on a PwmOut |
| dreschpe | 3:5a8242af60ba | 5 | * The class use a timeout to switch off the sound - it is not blocking while making noise |
| dreschpe | 3:5a8242af60ba | 6 | * |
| dreschpe | 3:5a8242af60ba | 7 | * Example: |
| dreschpe | 3:5a8242af60ba | 8 | * @code |
| dreschpe | 3:5a8242af60ba | 9 | * // Beep with 1Khz for 0.5 seconds |
| dreschpe | 3:5a8242af60ba | 10 | * #include "mbed.h" |
| dreschpe | 3:5a8242af60ba | 11 | * #include "beep.h" |
| dreschpe | 3:5a8242af60ba | 12 | * |
| dreschpe | 3:5a8242af60ba | 13 | * Beep buzzer(p21); |
| dreschpe | 3:5a8242af60ba | 14 | * |
| dreschpe | 3:5a8242af60ba | 15 | * int main() { |
| dreschpe | 3:5a8242af60ba | 16 | * ... |
| dreschpe | 3:5a8242af60ba | 17 | * buzzer.beep(1000,0.5); |
| dreschpe | 3:5a8242af60ba | 18 | * ... |
| dreschpe | 3:5a8242af60ba | 19 | * } |
| dreschpe | 3:5a8242af60ba | 20 | * @endcode |
| dreschpe | 3:5a8242af60ba | 21 | */ |
| dreschpe | 2:a34405c20cf5 | 22 | |
| dreschpe | 0:18e4a9c978ec | 23 | using namespace mbed; |
| dreschpe | 3:5a8242af60ba | 24 | // constructor |
| dreschpe | 2:a34405c20cf5 | 25 | /** Create a Beep object connected to the specified PwmOut pin |
| dreschpe | 3:5a8242af60ba | 26 | * |
| dreschpe | 3:5a8242af60ba | 27 | * @param pin PwmOut pin to connect to |
| dreschpe | 3:5a8242af60ba | 28 | */ |
| dreschpe | 2:a34405c20cf5 | 29 | |
| dreschpe | 0:18e4a9c978ec | 30 | Beep::Beep(PinName pin) : _pwm(pin) { |
| dreschpe | 0:18e4a9c978ec | 31 | _pwm.write(0.0); // after creating it have to be off |
| dreschpe | 0:18e4a9c978ec | 32 | } |
| dreschpe | 0:18e4a9c978ec | 33 | |
| dreschpe | 2:a34405c20cf5 | 34 | /** stop the beep instantaneous |
| dreschpe | 3:5a8242af60ba | 35 | * usually not used |
| dreschpe | 3:5a8242af60ba | 36 | */ |
| dreschpe | 0:18e4a9c978ec | 37 | void Beep::nobeep() { |
| dreschpe | 0:18e4a9c978ec | 38 | _pwm.write(0.0); |
| dreschpe | 0:18e4a9c978ec | 39 | } |
| dreschpe | 0:18e4a9c978ec | 40 | |
| dreschpe | 2:a34405c20cf5 | 41 | /** Beep with given frequency and duration. |
| dreschpe | 3:5a8242af60ba | 42 | * |
| dreschpe | 3:5a8242af60ba | 43 | * @param frequency - the frequency of the tone in Hz |
| dreschpe | 3:5a8242af60ba | 44 | * @param time - the duration of the tone in seconds |
| dreschpe | 3:5a8242af60ba | 45 | */ |
| dreschpe | 2:a34405c20cf5 | 46 | |
| dreschpe | 0:18e4a9c978ec | 47 | void Beep::beep(float freq, float time) { |
| dreschpe | 0:18e4a9c978ec | 48 | |
| dreschpe | 0:18e4a9c978ec | 49 | _pwm.period(1.0/freq); |
| dreschpe | 0:18e4a9c978ec | 50 | _pwm.write(0.5); // 50% duty cycle - beep on |
| dreschpe | 0:18e4a9c978ec | 51 | toff.attach(this,&Beep::nobeep, time); // time to off |
| dreschpe | 0:18e4a9c978ec | 52 | } |
| dreschpe | 0:18e4a9c978ec | 53 | |
| dreschpe | 0:18e4a9c978ec | 54 | |
| dreschpe | 0:18e4a9c978ec | 55 | |
| dreschpe | 0:18e4a9c978ec | 56 |