Simple Servo Control

Using Arduino Project Guidance
1

Hi,

I'm trying to control a Hi-Tec hs-645mg servo using the arduino uno. I copy and paste the sweep code and upload it to the arduino board, setting the code so that the servo will rotate from 60 to 150 degrees. When I hook up the servo (to an external power supply) it seems to move completely randomly. All my grounds are tied together as well.

Any help would be greatly appreciated!!

Thanks!!

2

Below is some simple servo code you can use to test youe servo. You don't say what the external power supply is, but the symptons are probably due to an inadequate servo power supply.

// 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="";
  } 
}