Simple Servo is freaking out

Using Arduino Motors, Mechanics, Power and CNC
1

Hey,
I'm new to arduinos and have come across a weird problem with a simple micro servo. I'm using the arduino uno. With servo wires Vcc plugged into +5v on arduino, ground on arduino and signal to digital 9. I'm running the following code. When I run the program the arduino immediately moves clockwise and never stops, it keeps pushing and spastically jittering against its limit angle.
The step motor handles angles <= 160degrees

Thanks!

Does anyone know what the problem could be?

#include <Servo.h> 
Servo myservo;
void setup() 
{ 
  myservo.attach(9); 
} 
void loop() { 
myservo.write(20);
delay(1000);
myservo.write(100);
delay(1000);
}
2

Spastic Servo Syndrome often happens when the servo is powered from the Arduino which cannot provide enough current. Give it its own power with ground common-ed to Arduino. That might solve the problem....

3

DrDuh:
the arduino immediately moves clockwise and never stops,

I doubt that you mean this literally. If you are more precise with your use of language it will be easier to help you.

...R

4

*Never stops trying to move right

Thanks for your replies

5

DrDuh:
*Never stops trying to move right

I was actually trying to draw your attention to the words "the arduino immediately moves"

I strongly suspect the arduino does NOT move.

...R

6

DrDuh:
*Never stops trying to move right

The usual suspects are inadequate power supply, inadequate ground between the servo and arduino, and a corrupt/bad servo control signal.