control for servo

Provide as many details about your hardware as you can.  Someone will help.  Explain how circuit performance failed to meet expectations.

Provide as many details about your hardware as you can.  Someone will help.  Explain how circuit performance failed to meet expectations.

i have an arduino duamilanavo ,servos and potentiometers ....

problem is that when potentiometer gives anlaog values then servo react accordingly  but analog value is vary according to time thats cause linearity of out put breaked

.

here is program

// Controlling a servo position using a potentiometer (variable resistor)

// by Michal Rinott <http://people.interaction-ivrea.it/m.rinott>

#include <Servo.h>

Servo myservo;  // create servo object to control a servo

int potpin = 0;  // analog pin used to connect the potentiometer

int val;    // variable to read the value from the analog pin

void setup()

{

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

}

void loop()

{

  val = analogRead(potpin);            // reads the value of the potentiometer (value between 0 and 1023)

  val = map(val, 0, 1023, 0, 179);     // scale it to use it with the servo (value between 0 and 180)

  myservo.write(val);                  // sets the servo position according to the scaled value

  delay(15);                           // waits for the servo to get there

}

I have never used Arduino, but se the comment I found that says: "you must call the SoftwareServo::refresh() method at least once every 50ms or so to keep your servos updating"

And I have seen example codes like yours but with one more line inside the loop. This one: - SoftwareServo::refresh();

Maybe this unlinearity is because of not refreshing the servos, is it posible?

Other posibility is that you have to set the minimum and the maximum pulse. This settings may vary depending on the sevo.

Hope it helps.

Potentionmeters come in linear taper and audio taper models.  That means there is an even increase of resistance as you turn the pot in linear taper, audio taper will increase the value logarithmically.  You might want to add a serial print to see the values the potentiometer is putting out through the IDE serial monitor so that you know the analog input is being scaled evenly to what you expect.

Use the sample sweep and servo sketch that is in your IDE.  Also, depending on the servo, if it is a continuous or just capable of 180 or fixed rotation, you may need to add logic to reset it or home it to zero, especially when it gets to it's end position and you have to reverse the direction for it to move.  The movements may be relative to the last postion too.