Matrix - Sound Sensor

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1 Introduction

Sound Sensor

• The Matrix-Sound_Sensor module is used to detect sound.
• The module has a variable resistor which can be used to control the threshold value of a sound level. Only when a sound level's value is greater than this threshold the module can detect it. Turning clockwise increases this threshold value. Turning anticlockwise decreases this value.
• By default this module's output level is high. When it detects sound signals its output level will turn low. When sound signals are not detected its output will turn high again without time delay.

2 Features

• Variable threshold value
• 2.54mm spacing pin interface
• PCB dimension (mm): 16 x 24

• Pin Description:

Pin	Description
S	GPIO
V	Supply Voltage 5V
G	Ground

3 Basic Device Operation

• The module contains an electret condenser microphone. Sound waves impinging on the diaphragm cause the capacitance between it and the back plate to change synchronously, this in turn induces an AC voltage on the back plate.
• This sound sensor functions like a microphone which receives sound waves and convert them to images which show the sound waves' vibration. When it receives a sound wave it will output 1 but cannot measure its strength.

4 Download Matrix Source Code

All the matrix modules' code samples are open source. They are maintained on GitHub - git://github.com/friendlyarm/matrix.git
Each branch in this hub contains the matrix modules' code samples for a board that the matrix modules can work with.

• The nanopi branch contains the matrix modules' code samples for the NanoPi
• The tiny4412 branch contains the matrix modules' code samples for the Tiny4412
• The raspberrypi branch contains the matrix modules' code samples for the RaspberryPi

Please follow the steps below to get the source code:
Install the git utility on a PC running Ubuntu14.04

$ sudo apt-get install git

Clone the matrix code from GitHub

$ git clone git://github.com/friendlyarm/matrix.git

If this is successful a "matrix" directory will be generated, which will contain all the matrix modules' code samples.

5 Connect to NanoPi

5.1 Preparations

Please install a Debian on a NanoPi and an appropriate cross compiler on a PC. Please refer to wiki :NanoPi
Compile a NanoPi kernel. Note: please use the kernel's source code from the nanopi-v4.1.y-matrix branch.

$ git clone https://github.com/friendlyarm/linux-4.x.y.git
$ cd linux-4.x.y
$ git checkout nanopi-v4.1.y-matrix
$ make nanopi_defconfig
$ touch .scmversion
$ make

5.2 Hardware Connection

Please refer to the following connection diagram to connect the Matrix-Sound_Sensor to the NanoPi

Connection Details:

Matrix-Sound_Sensor	NanoPi
S	Pin7
V	Pin4
G	Pin6

5.3 Compile Test Program

Please login the matrix hub and enter the nanopi branch

$ cd matrix
$ git checkout nanopi

Compile the matrix code

$ make CROSS_COMPILE=arm-linux- clean
$ make CROSS_COMPILE=arm-linux-
$ make CROSS_COMPILE=arm-linux- install

Note: please make sure to install the cross compiler "arm-linux-gcc-4.4.3" on your PC, which is used to compile files for the NanoPi-Debian.
Generated library files are under the "install/lib" directory. Applications are under the "install/usr/bin" directory. The test program for the "Matrix-Ultrasonic_Ranger" module is "matrix-ultrasonic_ranger".

5.4 Run Test Program

Please copy the library files and test program to the NanoPi

$ cp install/usr/bin/* nanopi_rootfs/usr/bin/
$ cp install/lib/* nanopi_rootfs/lib/ -d

Power on the NanoPi and run the following command in Debian's terminal

$ matrix-sound_sensor

5.5 Code Sample

static struct sensor sound[] = {
        {
                GPIO_PIN1,
                IRQ_TYPE_EDGE_BOTH,
        }
};
 
int main(void)
{
    int i;
    int retSize = -1;
    char value[ARRAY_SIZE(sound)];
    int devFD = -1;
    if ((devFD =sensorInit(sound, ARRAY_SIZE(sound))) == -1) {
        printf("Fail to init sensor\n");
        return -1;
    }
 
    if (( retSize = sensorRead(devFD, value, ARRAY_SIZE(sound)) ) == -1) {
        printf("Fail to read sensors\n");
    }
    if (retSize > 0) {
        i = 0;
        for(i=0; i<retSize; i++)
        {
            printf("sound[%d]:%d\n", i, value[i]);
        }
        printf("\n");
    }
    sensorDeinit(devFD);
    return 0;
}

6 与Tiny4412连接使用

6.1 准备工作

参考Tiny4412光盘里的《友善之臂Ubuntu使用手册》，在Tiny4412上运行UbuntuCore系统，然后在主机PC上安装并使用相应的编译器。
注意：只能使用Tiny4412SDK-1506的底板。

6.2 硬件连接

参考下图连接模块Matrix-Sound_Sensor和Tiny4412

连接说明：

Matrix-Sound_Sensor	Tiny4412
S	GPIO1 S
V	GPIO1 5V
G	GPIO1 GND

6.3 编译测试程序

进入Matrix代码仓库，切换到tiny4412分支

$ cd matrix
$ git checkout tiny4412

编译Matrix配件代码

$ make CROSS_COMPILE=arm-linux-gnueabihf- clean
$ make CROSS_COMPILE=arm-linux-gnueabihf-
$ make CROSS_COMPILE=arm-linux-gnueabihf- install

注意：请确保你的主机PC当前使用的交叉编译器为Tiny4412-UbuntuCore配套的arm-linux-gnueabihf-gcc-4.7.3。
编译出来的库文件位于install/lib目录下，而测试程序则位于install/usr/bin目录下，模块Matrix-Sound_Sensor对应的测试程序为matrix-sound_sensor。

6.4 运行测试程序

拷贝库文件和测试程序到Tiny4412的UbuntuCore的文件系统上

$ cp install/usr/bin/* tiny4412_rootfs/usr/bin/
$ cp install/lib/* tiny4412_rootfs/lib/ -d

然后启动Tiny4412，在UbuntuCore的shell终端中执行如下命令运行模块Matrix-Sound_Sensor的测试程序

$ matrix-sound_sensor

6.5 代码展示

static struct sensor sound[] = {
        {
                GPIO_PIN1,
                IRQ_TYPE_EDGE_BOTH,
        }
};
 
int main(void)
{
    int i;
    int retSize = -1;
    char value[ARRAY_SIZE(sound)];
    int devFD = -1;
    if ((devFD =sensorInit(sound, ARRAY_SIZE(sound))) == -1) {
        printf("Fail to init sensor\n");
        return -1;
    }
 
    if (( retSize = sensorRead(devFD, value, ARRAY_SIZE(sound)) ) == -1) {
        printf("Fail to read sensors\n");
    }
    if (retSize > 0) {
        i = 0;
        for(i=0; i<retSize; i++)
        {
            printf("sound[%d]:%d\n", i, value[i]);
        }
        printf("\n");
    }
    sensorDeinit(devFD);
    return 0;
}