How to make servo turn indefinitely?

Projects Programming
1

I am making an Arduino controlled car, for the wheels I had hoped to use servos. It seems that the only way to get the car to drive with servos is to use continuous servos.

I have seen modifications of servos to make them continuous, does that work?

I can turn the servos indefinitely with my hand so I assume their is no physical barrier stopping them from turning, so do I need to modify my servos at all, or is there some way to code the servo to keep turning?

2

If the servo you are talking about is a typical r/c servo that uses a PWM type signal, then as is stands, you can't make it turn more than about 270 degrees. When I did a modification some years back, I completely removed the internal electronics and the small potentiometer. I think there was a small gear wheel that drove the pot that also got removed.

After the mods, you basically end up with a motor and a gearbox.

3

An alternative is regular motors that you can get from any toy car (or buy) and an H-Bridge.

4

Hi,
Welcome to the forum.
Please read the post at the start of any forum , entitled "How to use this Forum".
OR
http://forum.arduino.cc/index.php/topic,148850.0.html.

I can turn the servos indefinitely with my hand so I assume their is no physical barrier stopping them from turning, so do I need to modify my servos at all, or is there some way to code the servo to keep turning?

There was a physical stop, but now you appear to have broken it, so you are halfway there to making a continuous servo.
You still need to do work internally to the servo as per the many conversion tutorials on the net.

Can you please tell us your electronics, programming, arduino, hardware experience?

Tom..... :slight_smile:

5

TomGeorge:
Can you please tell us your electronics, programming, arduino, hardware experience?

Not a lot. I've tried doing one Arduino project in the past.

6

emanresu01:
I can turn the servos indefinitely with my hand so I assume their is no physical barrier stopping them from turning, so do I need to modify my servos at all, or is there some way to code the servo to keep turning?

It sounds like you already have a 'continuous rotation servo'. Either that or any internal physical stops it or the internal pot had were broken off. What happens when you connect it to the Arduino and use File->Examples->Servo->Sweep? A regular servo will sweep back and forth about 180 degrees. A 'continuous rotation servo' will spin in one direction quickly, gradually slow to a stop, and then speed up in the other direction until it is spinning quickly the other way.

7

Unfortunately my servo just spins back and forth, not in one direction.

8

emanresu01:
Unfortunately my servo just spins back and forth, not in one direction.

OK, try this sketch:

#include <Servo.h>


Servo myservo;


void setup() 
{
  myservo.write(0);
  myservo.attach(9);  // attaches the servo on pin 9 to the servo object
}


void loop() {}

Does THAT make your servo spin in one direction?