Matrix - Buzzer

查看中文

1 Introduction

Buzzer

• The Matrix-Buzzer is a passive buzzer. To drive this buzzer an oscillating source generating 2K - 5K square waves is needed.
• It can be used in electronic devices that need sound generators.

2 Features

• 3 PIN interface
• PCB dimension (mm): 16 x 24

• Pin Description:

Pin	Description
V	Supply Voltage 5V
G	Ground
S	PWM Input

3 Basic Device Operation

A passive buzzer will not tweet if DC signals are used; instead, you need to use square waves whose frequency is between 2K and 5K to drive it. If you use GPIO signals to drive it you need to pull the GPIO high first and then low to generate oscillation. The oscillation frequency is generated by the time in which GPIO signals turn from high to low. The buzzer will generate different sounds based on different frequencies.

4 Applications

4.1 Connect to NanoPi 2

Refer to the following connection diagram to connect the module to the NanoPi M1

Connection Details:

Matrix-Buzzer	NanoPi 2
G	Pin6
V	Pin4
S	Pin22

4.2 Connect to NanoPi M2 / NanoPi 2 Fire

Refer to the following connection diagram to connect the module to the NanoPi M2/ NanoPi 2 Fire:

Connection Details:

Matrix-Buzzer	NanoPi M2
G	Pin6
V	Pin4
S	Pin12

4.3 Connect to NanoPC-T2

Refer to the following connection diagram to connect the module to the NanoPC-T2:
Matrix-Buzzer_nanopc_t2

Connection Details:

Matrix-Buzzer	NanoPC-T2
S	Pin23
V	Pin29
G	Pin30

5 Compile & Run Test Program

Boot your ARM board with Debian and copy the matrix code:

$ apt-get update && apt-get install git
$ git clone https://github.com/friendlyarm/matrix.git

If your cloning is done successfully a "matrix" directory will be generated.

Compile and install Matrix:

$ cd matrix
$ make && make install

Run test program:

$ matrix-pwm

Note: this module is not plug and play therefore before running the module please make sure it is connected to an ARM board.
Here is what you should observe:

Using default config: channel=0 freq=1000Hz duty=500
Press enter to stop PWM

You can hear the buzzer beeping. The range of the duty cycle is 0 ~ 1000. When you hit "enter" the buzzer will be stopped.

6 Code Sample

This Matrix code sample can work with all the ARM boards mentioned in this module's wiki. The name of this code sample is "matrix-pwm". Here is its source code:

int main(int argc, char ** argv)
{
    int Hz, duty, board;
 
    if ((board = boardInit()) < 0) {
        printf("Fail to init board\n");
        return -1;
    } 
 
    system("modprobe "DRIVER_MODULE);
    signal(SIGINT, intHandler);
    if (argc == 4) {
        // Usage:matrix-pwm channel freq duty[0~1000]
        pwm = atoi(argv[1]);
        Hz = atoi(argv[2]);
        duty = atoi(argv[3]);
    } else {
        Hz = 1000;
        duty = 500;
        printf("Using default config: channel=%d freq=%dHz duty=%d\n", pwm, Hz, duty);
    }
    if (PWMPlay(pwm, Hz, duty) == -1) {
        printf("Fail to output PWM\n");
    }  
    printf("Press enter to stop PWM\n");
    getchar();
    PWMStop(pwm);
    system("rmmod "DRIVER_MODULE);
 
    return 0;
}

For more details about this APIs called in this code sample refer to Matrix API reference manual

8 Update Log

8.1 Feb-23-2016

• Added the description for "NanoPi 2 branch" in Section 4
• Added Section 5: Connect to NanoPi 2

8.2 June-17-2016

• Re-organized and simplified wiki