#8 · Analog PS2 joystick with push button

Introduction

In this tutorial for beginners you learn how to read the direction and push button state from an analog Playstation 2 joystick. 😃

Course material

At the bottom of this page you'll find the course material button. This button allows you to download the code, circuit diagram and other files relevant to this Arduino tutorial.

Analog Playstation 2 joystick

In this Arduino tutorial we will use the analog PS2 joystick You can move this joystick continuously in all directions. This means that you can also measure how far the joystick is pushed in a certain direction.

The joystick is analog. This means that it can measure not only the direction, but also how far you press in a particular direction.

If you press the joystick straight down you can activate a push button. This can be useful, for example, to confirm a choice in a menu. If you look to the side of the joystick you can see the switch.

The joystick has 5 labeled pins:

• GND is the Earth (Ground)
• +5V is the 5V
• VRx is the analog x-axis (Variable Voltage x-axis)
• VRy is the analog y-axis (Variable Voltage y-axis)
• SW is the push button (Switch)

The circuit

Push the joystick into the breadboard and connect the following jumper wires to:

• The GND on the Arduino -> the GND pin of the joystick
• The 5V on the Arduino -> the +5V pin of the joystick
• The 12 on the Arduino -> the SW pin of the joystick
• The A0 on the Arduino -> the VRy pin of the joystick
• The A5 on the Arduino -> the VRx pin of the joystick

Arduino Code

We start the code by defining three constants for the pin numbers:

1 const int swPin = 12;
2 const int VrxPin = A5;
3 const int VryPin = A0;

• swPin is the pin to which we connected the push button
• VrxPin is the pin to which we connected the x-axis
• VryPin is the pin we connected the y-axis to

After this we define three more variables to store the read values of the axes and the push button:

1 int xDirection = 0;
2 int yDirection = 0;
3 int switchState = 1;

setup()

1 void setup() {
2   Serial.begin(9600);
3   pinMode(swPin, INPUT);
4   digitalWrite(swPin, HIGH);
5 }

First, we initialize the serial monitor. Then we set the swPin as input and make it HIGH. The push button is always HIGH and LOW when the button is pressed

loop()

The loop() function consists of 3 parts which are explained further below.

1 // repeat infinitely
2 void loop() {
3   xDirection = analogRead(VryPin);
4   yDirection = analogRead(VrxPin);
5 
6   switchState = digitalRead(swPin);
7 
8   Serial.print("Switch:  ");
9   Serial.println(switchState);
10 
11   Serial.print("X-axis:        ");
12   Serial.println(xDirection);
13 
14   Serial.print("Y-axis:        ");
15   Serial.println(yDirection);
16 
17   Serial.println("");
18 
19   if (!switchState) {
20       Serial.println("Switch pressed");
21   }
22 
23   if (xDirection < 480) {
24       Serial.println("Left");
25   } else if (xDirection > 520) {
26       Serial.println("Right");
27   }
28 
29   if (yDirection < 480) {
30       Serial.println("Down");
31   } else if (yDirection > 520) {
32       Serial.println("Up");
33   }
34 
35   delay(500);                  
36 }

Read and print values

We start with the analog reading of the analog values of the x and y-axis.

1 xDirection = analogRead(VryPin);
2 yDirection = analogRead(VrxPin);

After this we read out the push button 'digitally'. We use digitalRead() here because this push button has only two possibilities: pressed or not pressed.

1 switchState = digitalRead(swPin);

Then we print all the read values to the serial monitor:

1 Serial.print("Switch:  ");
2 Serial.println(switchState);
3 
4 Serial.print("X-axis:        ");
5 Serial.println(xDirection);
6 
7 Serial.print("Y-axis:        ");
8 Serial.println(yDirection);
9 
10 serial.println("");

Convert Joystick Push Button to Text

After this we will convert the read values to text. We start with the push button.

1 if (!switchState) {
2     Serial.println("Switch pressed");
3 }

The push button works in mirror image of what you may think. When you press it, the value becomes LOW. For this reason we use the !. This is the logical NOT. Actually we say: If the switch is not HIGH then you print the text.

🎓 Can you write this if so that we don't need the ! but

1 if (switchState) {

can use?

Convert joystick direction to text

The analog values on the Arduino range from 0 to 1023. So the center should be exactly at 512.

1 if (xDirection < 480) {
2     Serial.println("Left");
3 } else if (xDirection > 520) {
4     Serial.println("Right");
5 }

In the code we see that the piece between 480 and 520 is seen as the middle. This is because the analog values are not super precise. It is therefore perfectly possible that the center of your joystick has a value of 490. So we're deliberately taking a little margin before we say the joystick is left or right.

1 if (yDirection < 480) {
2     Serial.println("Down");
3 } else if (yDirection > 520) {
4     Serial.println("Up");
5 }

For the y-axis we do exactly the same only now for the yDirection variable.

Upload code to Arduino

Our program is now ready to be sent to the Arduino. Then open the serial monitor:

Tools ▸ Serial Monitor

Now move with the joystick and press the top. You should see the direction and condition of the print head on your serial monitor.