running 2 servos at once

Using Arduino Programming Questions
1

hi,
I am wanting to run to servos at once on the one UNO, I have one 6 V power supply to the board and here is my sketch, however I can only get one servo to move not both at the same time ?

thanks
ian

/* Sweep
by BARRAGAN http://barraganstudio.com
This example code is in the public domain.

modified 8 Nov 2013
by Scott Fitzgerald

*/

#include <Servo.h>

Servo myservo; // create servo object to control a servo
// twelve servo objects can be created on most boards

int pos = 0; // variable to store the servo position

void setup()
{
myservo.attach(9); // attaches the servo on pin 9 to the servo object
myservo.attach(8); // attaches the servo on pin 9 to the servo object
}

void loop()
{
for(pos = 0; pos <= 20; pos += 1) // goes from 0 degrees to 180 degrees
{ // in steps of 1 degree
myservo.write(pos); // tell servo to go to position in variable 'pos'
delay(15); // waits 15ms for the servo to reach the position
}
for(pos = 20; pos>=89; pos-=1) // goes from 180 degrees to 0 degrees
{
myservo.write(pos); // tell servo to go to position in variable 'pos'
delay(15); // waits 15ms for the servo to reach the position
}
for(pos = 0; pos <= 20; pos += 1) // goes from 0 degrees to 180 degrees
{ // in steps of 1 degree
myservo.write(pos); // tell servo to go to position in variable 'pos'
delay(15); // waits 15ms for the servo to reach the position
}
for(pos = 20; pos>=89; pos-=1) // goes from 180 degrees to 0 degrees
{
myservo.write(pos); // tell servo to go to position in variable 'pos'
delay(15);
}
}

2 
myservo.attach(9);  // attaches the servo on pin 9 to the servo object 
  myservo.attach(8);  // attaches the servo on pin 9 to the servo object

Did you mean to have two Servo objects attached to two different pins?

If you want to drive two servos from one pin, just wire both signal pins on the servo to the same pin and do a single "attach".

3

yes i mean two servos at different pins like 8 and 9
thanks

4

(uncompiled, untested)

#include <Servo.h>
 
Servo myservo [2];
 
int pos = 0;    // variable to store the servo position
 
void setup()
{
  myservo[0].attach(9);
  myservo[1].attach(8);
}
 
void loop()
{
  for(pos = 0; pos <= 20; pos += 1) // goes from 0 degrees to 20 degrees

    myservo[0].write(pos);
    myservo[1].write(pos);
    delay(15);                 
  }
  // etc, etc
}
5 
Servo myservo;  // create servo object to control a servo 
                // twelve servo objects can be created on most boards

It is true that you can create several servo objects but they need to have different names otherwise when you do

myservo.write(pos);

how will the program know which servo to move ?