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Topic: 2 servos controlled with mouse in processing (Read 2 times) previous topic - next topic


hi there
i am using this code which has 2 servos on digital pins 9, 10. i found this code from another post in the arduino forums
code is
Code: [Select]
#include <Servo.h>

Servo servo1; Servo servo2;

void setup() {


void loop() {

 static int v = 0;

 if ( Serial.available()) {
   char ch = Serial.read();

   switch(ch) {
     case '0'...'9':
       v = v * 10 + ch - '0';
     case 's':
       v = 0;
     case 'w':
       v = 0;
     case 'd':
     case 'a':

and my processing code which i found on http://www.arduino.cc/playground/Learning/SingleServoExample
Code: [Select]
* Servocontrol (derived from processing Mouse 1D example.)
* Updated 24 November 2007

// Use the included processing code serial library
import processing.serial.*;        

int gx = 15;
int gy = 35;
int spos=90;

float leftColor = 0.0;
float rightColor = 0.0;
Serial port;                         // The serial port

void setup()
 size(720, 720);
 colorMode(RGB, 1.0);

 println(Serial.list()); // List COM-ports

 //select second com-port from the list
 port = new Serial(this, Serial.list()[1], 19200);

void draw()
 rect(150, 320, gx*2, gx*2);
 fill(180 - (mouseX/4));
 rect(450, 320, gy*2, gy*2);

void update(int x)
 //Calculate servo postion from mouseX
 spos= x/4;

 //Output the servo position ( from 0 to 180)

 // Just some graphics
 leftColor = -0.002 * x/2 + 0.06;
 rightColor =  0.002 * x/2 + 0.06;

 gx = x/2;
 gy = 100-x/2;


now the problem is that only the servo on pin 9 works. the servo on pin 10 does not move at all.
i have also checked my connections by attaching the 2nd servo on pin 10 to pin 9 to see if the connections are wrong and it worked.

could you please help me get both servos working??

many thanks in advance!



You might give Bitlash a try to debug the servos from the command line.  There's a blog post here with examples: http://www.entropymouse.com/blog/blog:bitlash_1.1_and_servo_mayhem

Bitlash is here: http://bitlash.net

Once you have the servos happy you can either modify your Processing sketch to send Bitlash commands, or go back to the code you have in hand and continue debugging.

Happy hacking,


Andy R

Switching the motors was smart. You proved the motor is wired right. Of course there could be some issue with pin 10 or using two adjacent pins.

The next clever thing to do is run the sketch from the Arduino serial monitor. Also have the sketch echo back what it is doing:
case 'w':
        Serial.write("servo2.write("); Serial.write(v);Serial.writeln(");
       v = 0;

Think of testing with the serial monitor as unit testing the Arduino sketch. You want to make sure that works as expected before introducing Processing. Check that the servo is attached to pin 10 and the value in Serial.write(v).

After this, I would try a different port or a different servo library. Define the ports at the top of your sketch so you can  change them easily. But first make sure your Arduino and the library supports pwm on the pin. Early versions of Servo only supported pins 9 and 10.


Jun 12, 2010, 01:53 pm Last Edit: Jun 12, 2010, 02:55 pm by Fredx Reason: 1
m56789, if you get the code working, please post it here.
I have also been trying to do that kind of project, so far no luck.

I am trying to do something like this:


Jun 12, 2010, 02:31 pm Last Edit: Jun 12, 2010, 02:55 pm by Fredx Reason: 1
Here is something: http://www.arduino.cc/playground/ComponentLib/Ps2mouse. On that page it is written - "There are NO external components needed: you can wire the mouse directly to the arduino. "

I have an old optical mouse which i'd like to use... BUT i have heard, that Arduino can handle current max 40 mA. Behind my optical mouse there is written 5V - 100mA. So is it safe to connect it directly to Arduino?

Does anyone know if mice with ball consume less current (mA)?

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