Servo jitter - me too

Well, I saw another post about this, with no real solutions.

My servo, jitters and shakes the robot (steering servo). Sometimes the throttle control does the same thing. Well, it causes the robot to jump forward and back...

I think it is because of these thin wires, and bad connections on the data wires. I have no idea. I am contemplating a screw terminal module, like this one

const int Strait = 90;//      
const int Left = 65;//  
const int Right = 115;//

Next is in setup();


then I call for a change later


very simple, and yet, it shakes and jitters. How do I fix this? I have tried several different delays after the steeringPin.write(Left); With or without the delay, it shakes and fails to work correctly. The power to the servo is 5V, from a separate power supply than the Arduino.

Simple servo test code you can try to see if the servo jitters with this code.

//zoomkat 7-30-10 serial servo test
//type servo position 0 to 180 in serial monitor
// 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.println("servo-test"); // so I can keep track of what is loaded

void loop() {

  while (Serial.available()) {
    char c =;  //gets one byte from serial buffer
    readString += c; //makes the String readString
    delay(2);  //slow looping to allow buffer to fill with next character

  if (readString.length() >0) {
    Serial.println(readString);  //so you can see the captured String 
    int n = readString.toInt();  //convert readString into a number
    Serial.println(n); //so you can see the integer

If your code is putting out a constant value and the servo is jittering then there is something wrong with your wiring.

There is always about a 30% error rate with these products.

What products? Link please.

Grumpy_Mike: What products? Link please.

I think he means the screw terminal shield

He said:-

I am contemplating a screw terminal module,

Which means he hasn’t got one yet. His post is poorly worded and it is not clear what products this screw terminal module or indeed screw terminal shield actually is. A link would clear it up.

I you have higher voltage servos and a higher voltage power source, do not share the ground.

No that is wrong. If you think it improved things then you are misunderstanding something.

Use diodes where needed to restrict the flow of electricity (one way energy flow).

No idea what that means but it sounds wrong in this context. You probably need supply decoupling rather than diodes.

I suspected bad distance reads where due to power surges on the one battery system

You don't get any power surges on a battery, so I don't know what you mean.

Supply decoupling and common grounds are vital, reading these links might help you:-

I had one of my motors connected to a 3.3V power supply, and it jittered extremely bad. I asked a hobbyist and he said it wasn't getting enough power. I connected mine to a 6V power supply and no jitters!

So, to help, regardless of what others think, separate your power.

That is not a help regardless of what you might think. It is a propagation of miss information.

because sometimes people don't pay attention and ground more than one power supply together

ALL power supplies must have their grounds connected together did you not read the link.

Using the proper words is important. Doctor I have cut off my leg, sorry I should have said hair.

This forum is where you get good solid advice not poor badly thought out superstition like you are giving. If you are seeing an effect when doing an experiment that runs counter to logic then there is something wrong with the experiment. You can not reinvent the laws of physics just because you don't understand them.

To quote the decoupling article, ......

Did you spot I wrote that artical?

Ok, well, I’m going to remove my posts, so others don’t get confused

Anyone looking here for help, check your power connections and read the referenced articles above.

Ok, well, I’m going to remove my posts, so others don’t get confused

. . . which makes a complete nonsense of other peoples’ replies.

Well done.