Arduino + 2 Servos + Mouse




Introduction: Arduino + 2 Servos + Mouse

About: Evo 8, Honda K, B Engines Mods
Here is a tutorial on how to make 2 servos move with a mouse using the Arduino board.
There is not a simple tutorial than this one and I have search the web looking for one with no result.
This one is simple and easy for everybody to follow. Enjoy! ;)
Dont forget to vote for me on the Arduino Challenge!!

Note: This tutorial is for those who are using the Arduino already. But If you haven't just yet with this tutorial you can.

Step 1: Materials

You will need the following: (not in a particular order)

1. Arduino Board (my version is UNO).
2. 2 servos Parallax (Radio Shack).
3. Web Cam (optional) to see the movement.
4. 2 rubber bands to hold the Webcam in position.
5. Bread Board to make any connections easy.
6. 1 cable tie
7. Something to hold the servos in place.
8. A computer.                  

1. Arduino Software (to upload the code to move the 2 servos).
2. Process Software (to move the servos using the mouse)

Step 2: Connections

Before you upload the code or use the Process sofware. You must connect
the servos using the picture.
Be advice that I label  the servos so I can hook them the right way.
Also this works when connecting the webcam  to them, you can see witch one
goes up & down and witch one goes right & left.
Follow the diagram for more help.
I have use a bread board to make the connections easy.
Connections: (each servo)
Black to GND
Red to 5V
Yellow or White to Analogs 0 and Analog 1
(Use the bread board to provide 5v to each servo)

Step 3: Arduino Software

After all the connections were made please double check them always.
Connect the Arduino Board to the computer. (USB cable)
Open the arduino Software
a) copy and paste the code in the arduino sketch
b) Always verify any code you upload, this saves you time.
c) After you verify the code, proceed to upload it to the Arduino board.
d) Close the Arduino Software.

Here is the code: ( I have tested this code several times before I pasted it here

//Arduino code:
#include <Servo.h>

Servo yservo;  Servo xservo; // servos for x and y
//set initial values for x and y
int ypos = 0;
int xpos= 0;

void setup(){
  xservo.attach(14); //(analog pin 0) for the x servo
  yservo.attach(15);  //(analog pin 1) for the y server

  Serial.begin(19200); // 19200 is the rate of communication
  Serial.println("Rolling"); // some output for debug purposes.


void loop() {
  static int v = 0; // value to be sent to the servo (0-180)
  if ( Serial.available()) {
    char ch =; // read in a character from the serial port and assign to ch
    switch(ch) { // switch based on the value of ch
      case '0'...'9': // if it's numeric
        v = v * 10 + ch - '0';
           so if the chars sent are 45x (turn x servo to 45 degs)..
           v is the value we want to send to the servo and it is currently 0
           The first char (ch) is 4 so
           0*10 = 0 + 4 - 0 = 4;
           Second char is 4;
           4*10 = 40 + 5 = 45 - 0 = 45;
           Third char is not a number(0-9) so we  drop through...
      case 'x': // if it's x
       ....and land here
       where we send the value of v which is now 45 to the x servo
       and then reset v to 0
        v = 0;
      case 'y':
        v = 0;

Step 4: Processing Software

Leave the Arduino Board connected to the computer.
Open Processing Software.

a) Copy and paste the code.(there is a value that you can paly with is in line 17 :port = new Serial(this, Serial.list()[0], 19200); The [0] in bold is the value you can change and it is for the size of the box to control the servos you can put 0,1,2,3 but I prefer 0 because is the right size for me.
b) Click Run.
c) If you follow everything correct you will see a gray box
    next to the Processing Software. Move the mouse pointer
    to that area to start moving the servos.(green is for up & down, red is for right & left).
Note: The box is very sensitive so it means that when you finish paying with the servos
          you should put the two marks in the middle and disconnect the board.
          If not then the servos will keep running and it would damage them unless you have a 
          fully 360 rotating servo.  


//Processing code:
import processing.serial.*;       

int xpos=90; // set x servo's value to mid point (0-180);
int ypos=90; // and the same here
Serial port; // The serial port we will be using

void setup()
  size(360, 360);
  println(Serial.list()); // List COM-ports
  //select second com-port from the list (COM3 for my device)
  // You will want to change the [1] to select the correct device
  // Remember the list starts at [0] for the first option.
  port = new Serial(this, Serial.list()[0], 19200);

void draw()
  fill(255,0,0); //rgb value so RED
  rect(180, 175, mouseX-180, 10); //xpos, ypos, width, height
  fill(0,255,0); // and GREEN
  rect(175, 180, 10, mouseY-180);
  update(mouseX, mouseY);

void update(int x, int y)
  //Calculate servo postion from mouseX
  xpos= x/2;
  ypos = y/2;
  //Output the servo position ( from 0 to 180)

Step 5: Troubleshooting

Common problems of this project:
1. The servos do not move after follow all the directions. 
A. Double check the connections, If not then the servos don't work.
2. The code do not compile on Arduino Software.
A. Double check that at the end were the last key } is there is no space.
3. When copy code to Processing Software  and click Run there is an error.
A. This happens because you have the arduino Software open. After upload the code to the board close it the click run
     or start the Processing Software part again.
4. I change the :port = new Serial(this, Serial.list()[0], 19200);  value to 1,2 or 3 and there is an error.
A. Then leave the value to [0] and it will work.
5. How to provide 5V to both servos at the same time.
A. Use the bread Board for this. (look at the picture).

Any other queations  please leave a comment and I will be glad to help you. ;)

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Question 2 years ago

If my left and right controls are inverted so like left moves it right and right move it left how do i get it to switch???


5 years ago

I want to control 4 motore is possible to do that ?
Please can u help


5 years ago

HI there i make this

do wan't to see the video click the link


6 years ago

Arduino Mega does not work, the problem may be the mega?


6 years ago

I used your code in a project. I would like to control 6 servos by 6 knobs through serial. I tried with only one servo, but it works with every knobs. I identify the servos by letters like a,b,c,d,e,f. ....any idea? Can I use multiple port.write() function? If anybody can help I would send my code.


7 years ago

runs great through serial moniter but running it on micro i had to move the servos to 8 and 9

processing code doesnt like me for some reason though

doesnt want COM10 and says there is an error at line 11


Reply 6 years ago

i also got an error on line 11. did you ever resolve this by chance?


6 years ago

How do i choose Com-Port?
COM1 and COM5 are listed in the console, but i can't choose either of them


7 years ago

Why are analog pins used and can other pins be used instead?


7 years ago

Hi - thank you so much for teaching me a lot about servo control via Processing and Arduino.

I am building a GUI for a scientific instrument using CP5 in Processing and standardanalogfirmata on the arduino side. Is there a way to integrate your servo code with the safirmata code? I've tried a few experiments but they all failed. I can control the servos but they do not behave nearly as ideally using safirmata as they do with your arduino sketch and the servo.h include - I need to use the firmata.h include for the other controllers - any advice would be much appreciated! Thanks in advance. Eric.


7 years ago

this is a nice project

and please send me the code for same project but with adxl 335(accelerometer)

it would help me a lot


please send on this email (


7 years ago

Hi! biomech75, u can do it with dc servo??


Reply 7 years ago

yes but you need the motor shield for that and they are not that precise

anto pV
anto pV

7 years ago on Introduction

my project involve measuring the distance to an object. i want my servos to point at the object that i want to measure the distance to. is there any way i can superimpose the image from a camera so that i can see the object on the processing screen, and when i place my mouse over the object the servos point at it?

sir, kindly inform me soon, because i am working on my final year project. I am working on a robotic arm control by a mouse.the mouse is directly connected to arduino uno not to computer.

sir kindly inform me that,can i connect mouse to arduino uno directly or not.


8 years ago on Introduction

Thank you a lot for this tutorial . It worked effortlessly .

The question i have is can you just modify the code so that my servo's remain stable at all position . I mean the point that you mentioned about spoiling the servo's .