can't make both servos move at once.

Forum 2005-2010 (read only) Hardware Interfacing
1

Hi, i can't seem to get both servos to move at once. i am using a modified version of "sweep."

heres the code im using.

// Sweep
// by BARRAGAN <http://barraganstudio.com> 

#include <Servo.h> 
 
Servo myservo1;  // create servo object to control a servo 
Servo myservo2;                // a maximum of eight servo objects can be created 
int ledPin = 13;
int pos = 0;    // variable to store the servo position 
 
void setup() 
{ 
  myservo1.attach(10,700,2400);  // attaches the servo on pin 9 to the servo object 
  myservo2.attach(9,700,2400); 
  
} 
 
 
void loop() 
{ 
  for(pos = 0; pos < 180; pos += 1)  // goes from 0 degrees to 180 degrees 
  {                                  // in steps of 1 degree 
    myservo1.write(pos);              // tell servo to go to position in variable 'pos' 
    delay(5);                       // waits 15ms for the servo to reach the position 
  } 
    for(pos = 90; pos < 125; pos +=1)
  {
    myservo2.write(pos);
    delay(25);
  }
  for(pos = 125; pos>=60; pos-=1)
  {
    myservo2.write(pos);
    delay(25);
  }
  for(pos = 60; pos < 90; pos +=1)
  {
    myservo2.write(pos);
    delay(25);
  }
  
  for(pos = 180; pos>=1; pos-= 1)     // goes from 180 degrees to 0 degrees 
  {                                
    myservo1.write(pos);              // tell servo to go to position in variable 'pos' 
    delay(5);                       // waits 15ms for the servo to reach the position 
  } 
  for(pos = 90; pos < 125; pos +=1)
  {
    myservo2.write(pos);
    delay(25);
  }
  for(pos = 125; pos>=60; pos-=1)
  {
    myservo2.write(pos);
    delay(25);
  }
  for(pos = 60; pos < 90; pos +=1)
  {
    myservo2.write(pos);
    delay(25);
  }
 
}

what am i doing wrong?

2

In what way does that code not work?

3

Those values are a little extreme and some servos may not be able to respond to 700us or 2400us

Try attach using :
myservo1.attach(10,1000, 2000);
myservo2.attach 9,1000, 2000;

If that still doesn't work and you are sure you have wired the servos correctly then try using external power for the servos

4

both servos work perfectly. But i can't get them to move at the same time. what i mean is, one servo swivels, while the other does nothing, when the one servo is done turning, the other starts it cycle.

i want both servos to move at the same time, but i cant get it to do that.

:edit: heres a video of whats going on. I want the top to move up and down while the bottom swivels back and forth.

5

You need to tell the servos to move at the same time if you want them to do that
Try this code in loop

void loop()
{
  for(pos = 0; pos < 180; pos += 1)  // goes from 0 degrees to 180 degrees
  {                                  // in steps of 1 degree
    myservo1.write(pos);              // tell servo to go to position in variable 'pos'
    myservo2.write(180 -pos);              // tell servo to go to position in variable 'pos'
    delay(5);                       // waits 15ms for the servo to reach the position
  }
    for(pos = 90; pos < 125; pos +=1)
  {
    myservo2.write(pos);
    myservo1.write(180-pos);
    delay(25);
  }
}

those look like beefy servos - you may need a seperate power source to move both of them at the same time.

6

thanks! ill try that soon. so far i haven't had any problems with running both servos at once, whenever i use the potentiometers to control them they have no problems at all

7