Joseph Roberts
Make noise with a piezo buzzer. Use a digital out pin.
Fork of
beep
by 
Peter Drescher
This is a simple non blocking library to turn on the pin passed into the constructor for the amount of time specified when calling the beep(float time) function.
I use it to turn on a buzzer but it could be used for anything you need to turn on for a set time.
beep.c@0:18e4a9c978ec, 2011-02-01 (annotated)
- Committer:
- dreschpe
- Date:
- Tue Feb 01 18:44:45 2011 +0000
- Revision:
- 0:18e4a9c978ec
- Child:
- 2:a34405c20cf5
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 | 0:18e4a9c978ec | 4 | using namespace mbed; |
| dreschpe | 0:18e4a9c978ec | 5 | // constructor |
| dreschpe | 0:18e4a9c978ec | 6 | Beep::Beep(PinName pin) : _pwm(pin) { |
| dreschpe | 0:18e4a9c978ec | 7 | _pwm.write(0.0); // after creating it have to be off |
| dreschpe | 0:18e4a9c978ec | 8 | } |
| dreschpe | 0:18e4a9c978ec | 9 | |
| dreschpe | 0:18e4a9c978ec | 10 | // switch off |
| dreschpe | 0:18e4a9c978ec | 11 | void Beep::nobeep() { |
| dreschpe | 0:18e4a9c978ec | 12 | _pwm.write(0.0); |
| dreschpe | 0:18e4a9c978ec | 13 | } |
| dreschpe | 0:18e4a9c978ec | 14 | |
| dreschpe | 0:18e4a9c978ec | 15 | |
| dreschpe | 0:18e4a9c978ec | 16 | // beep |
| dreschpe | 0:18e4a9c978ec | 17 | void Beep::beep(float freq, float time) { |
| dreschpe | 0:18e4a9c978ec | 18 | |
| dreschpe | 0:18e4a9c978ec | 19 | _pwm.period(1.0/freq); |
| dreschpe | 0:18e4a9c978ec | 20 | _pwm.write(0.5); // 50% duty cycle - beep on |
| dreschpe | 0:18e4a9c978ec | 21 | toff.attach(this,&Beep::nobeep, time); // time to off |
| dreschpe | 0:18e4a9c978ec | 22 | } |
| dreschpe | 0:18e4a9c978ec | 23 | |
| dreschpe | 0:18e4a9c978ec | 24 | |
| dreschpe | 0:18e4a9c978ec | 25 | |
| dreschpe | 0:18e4a9c978ec | 26 |