04-07 OrangesAndLemons
From Manuals
This example uses a PWM to play the tune "Oranges and Lemons" on a piezo buzzer using a PWM.
The signals used for this example are listed below:
| Signal | LPC4330 PIN NAME | BAM210E | BAM210 | BAM200E | BAM200 | Used for |
| PWM1 | P1_7 | J9-3 | J9-3 | S2-3 | S2-3 | Buzzer |
The following schematic can be used to build the circuit with a BAM210E or BAM210.
Schematic for example 04-07
/*Program Example 4.7: Plays the tune "Oranges and Lemons" on a piezo buzzer, using PWM
*/
#include "mbed.h"
PwmOut buzzer(PWM1);
//frequency array
float frequency[]= {659,554,659,554,440,494,554,587,494,659,554,440};
float beat[]= {1,1,1,1,1,0.5,0.5,1,1,1,1,2}; //beat array
int main()
{
while (1) {
for (int i=0; i<=11; i++) {
buzzer.period(1/(2*frequency[i])); // set PWM period
buzzer=0.5; // set duty cycle
wait(0.4f*beat[i]); // hold for beat period
}
}
}
The following image shows the built circuit on a BAM210E.
