hold the postion

Projects Programming
1

hey...i want to control the position of the servo motor...i want it to turn then hold the position..but why the servo keep turn back to 0 degree then rotate it back.
here the coding

// 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 
 
 // 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=140;    // 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 
}

how to make the servo hold the postion and never rotate it back?

2

You only ever send it to 140 "degrees" - when does it return to zero?

3

yes it will go to 140 degree..and the back to postion 0 degree..and it keep looping..

it spouse hold the position 140 degree right?

4

OK, I'll try again.
When does it return to zero?

5

when it go to 180, in second it will back to 0 again.the keep repeating

6

OK, sounds like your board is resetting.
How are you powering all of this?

7

arduino is from usb, servo from external 6.3V

8

hw to hold the servo

9

hw to hold the servo

In English?

10

Some servo test code you can try to see if the servo behaves the same.

// zoomkat 10-4-10 serial servo test
// type servo position 0 to 180 in serial monitor
// for writeMicroseconds, use a value like 1500
// for IDE 0019 and later
// Powering a servo from the arduino usually DOES NOT WORK.

String readString;
#include <Servo.h> 
Servo myservo;  // create servo object to control a servo 

void setup() {
  Serial.begin(9600);
  myservo.attach(7);  //the pin for the servo control 
  Serial.println("servo-test-21"); // so I can keep track of what is loaded
}

void loop() {

  while (Serial.available()) {
    delay(1);  
    if (Serial.available() >0) {
      char c = Serial.read();  //gets one byte from serial buffer
      readString += c; //makes the string readString
    } 
  }

  if (readString.length() >0) {
    Serial.println(readString);  //so you can see the captured string 
    int n;
    char carray[6]; //converting string to number
    readString.toCharArray(carray, sizeof(carray));
    n = atoi(carray); 
    myservo.writeMicroseconds(n); // for microseconds
    //myservo.write(n); //for degees 0-180
    readString="";
  } 
}
11

I tried your code from the original post and it worked perfectly. The motor did not return. I suspect a hardware problem.

12

You might want to expand. We are trying to help you and you give us minimal information.

  • What board are you using?
  • What motor? (Description, model number)
  • What is the rating of the motor? (eg. current, voltage needed to power it)
  • How is it wired?
  • What is this external 6.3V supply? Sounds an odd voltage to have lying around.
  • How much current can the 6.3V supply deliver?
  • What board or other gadget (eg. transistors) are you using to power the motor from the Arduino pins? Please provide a wiring diagram.
  • How about a photo of the setup?
13

yes it will go to 140 degree..and the back to postion 0 degree..and it keep looping..

it spouse hold the position 140 degree right?

...

when it go to 180, in second it will back to 0 again.the keep repeating

Well does it go to 140 or 180 degrees? Does it pause for a second exactly?

You know you have the code in "loop" right? Try putting it in setup instead.

14

thanks all..and Nick Gammon
it seem my hardware have the problem..when i try it using my MEGA it work perfectly, but when i try it on my Duemilanove the problem occur.
i think the problem is on my duemilanove