Matrix - Joystick

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1 Introduction

Joystick

• The matrix-joystick module is a two-axis stick module. It consists of two Sliding rheostats and one button. It has two analog outputs and one digital output. Its positional states can be measured as X and Y axis values as the calibrated resistance of the two potentiometers.
• When you move the joystick the sliding rheostats' resistance will change and the corresponding x/y values will change too. When you push the joystick the SW level will turn low.

2 Features

• X and Y axis, and one button
• 2.54mm spacing pin
• PCB dimension(mm): 24 X 32

• Pin Description:

Pin	Description
GND	Ground
5V	Supply Voltage 5V
SW	Button
X	X Axis
Y	Y Axis

3 Basic Device Operation

• It has two analog outputs and one digital output. The two analog outputs are measured as X and Y values as the calibrated resistance of the two potentiometers. The digital output is measured as Z value indicating whether or not the button is pressed.
  
• We extend all three outputs: X, Y and Z and users can use them easily.

4 Applications

The Matrix-Joystick module outputs analog signals which can be converted to digital signals with an ADC converter e.g. the Matrix-Analog_to_Digital_Converter.
For more details about the Matrix-Analog_to_Digital_Converter module refer to wiki: Matrix_-_Analog_to_Digital_Converter.

4.1 Connect to NanoPi M1

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

Connection Details:

Matrix-Joystick
GND	NanoPi M1 Pin9
5V	NanoPi M1 Pin2
X	Matrix-Analog_to_Digital_Converter A1
Y	Matrix-Analog_to_Digital_Converter A2

4.2 Connect to NanoPi 2

Refer to the following connection diagram to connect the module to the NanoPi 2:

Connection Details:

Matrix-Joystick
GND	NanoPi 2 Pin9
5V	NanoPi 2 Pin2
X	Matrix-Analog_to_Digital_Converter A1
Y	Matrix-Analog_to_Digital_Converter A2

4.3 Connect to NanoPi M2 / NanoPi 2 Fire

Refer to the following connection diagram to connect the module to the NanoPi M2/ NanoPi 2 Fire:
Matrix_Joystick_nanopi_m2

Connection Details:

Matrix-Joystick
GND	NanoPi M2 Pin9
5V	NanoPi M2 Pin2
X	Matrix-Analog_to_Digital_Converter A1
Y	Matrix-Analog_to_Digital_Converter A2

4.4 Connect to NanoPC-T2

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

Connection Details:

Matrix-Joystick
GND	NanoPC-T2 USB Host GND
5V	NanoPC-T2 USB Host 5V
X	Matrix-Analog_to_Digital_Converter A1
Y	Matrix-Analog_to_Digital_Converter A2

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-joystick

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:

x=1280 y=1280

When you move the stick you will see X and Y's value changes.

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-joystick". Here is its source code:

int main(int argc, char ** argv)
{
    int i = 0;
    int x, y, board;
 
    x = y = 0;
    if ((board = boardInit()) < 0) {
        printf("Fail to init board\n");
        return -1;
    }
 
    system("modprobe "DRIVER_MODULE);
    signal(SIGINT, intHandler);
    for (i=0; i<PS2_READ_TIMES; i++) {
        if (pcf8591Read(1, &x) != -1 && pcf8591Read(2, &y) != -1) {
            printf("x=%4d y=%4d\n", x, y);
        }
    }
    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