Knob(s) for servo(s)

Forum 2005-2010 (read only) Hardware Interfacing
1

Hi there,
I have an arduino diecimila, my question is:
It is possible to have 2 knobs controling 2 diffrent servos?
(I used the knob example (servos=>knob) but I don't have the knowledge to change this code to fit another set of potentiometer + 2nd servo).

THANKS!
Eran

2

It is possible :slight_smile:

Just mocked up some code: [UNTESTED]

// 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
Servo myservo2; // create servo object to control a servo

byte potpin1 = 0; // analog pin used to connect the potentiometer
byte potpin2 = 1; // analog pin used to connect the second 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
myservo2.attach(10); // attaches the servo on pin 10 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

val = analogRead(potpin2); // 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)
myservo2.write(val); // sets the servo position according to the scaled value
delay(15); // waits for the servo to get there
}

3

Do you need to have both delays in there? Wouldn't one delay at the end cover both servo's travel times?

4

A single delay after writing the values to both servos will be sufficient.

5

Hmm, I didn't know about the map function. Interesting and handy!

6

Thank you,
I will try it and let you all know the results.

Another question - how can I add a THIRD potentiometer that will control the speed of a regular dc motor?

7

There is a playground article here that may help:
http://www.arduino.cc/playground/Main/DCMotorControl