How to program a servo for continuous rotation?

Projects Programming
1

How does programming change for a servo that's now modified for continuous rotation?
Does it still use the signal wire or will it move with just voltage applied?

Thanks,
Mike

2

A continuous rotation "servo" can be controlled by the Servo library using the output from a digital pin as normal but instead of position control you get speed and direction control. To do this it uses the signal wire as well as 5V and GND

Note that unless the "servo" is tiny it should not be powered from the Arduino 5V output but rather from an external power supply with common GNDs.

3

UKHeliBob:
A continuous rotation "servo" can be controlled by the Servo library using the output from a digital pin as normal but instead of position control you get speed and direction control. To do this it uses the signal wire as well as 5V and GND

Note that unless the "servo" is tiny it should not be powered from the Arduino 5V output but rather from an external power supply with common GNDs.

Thanks. Do you control it using servo.write or servo.writeMicroseconds?

Also, if you send it a constant pulse @ lets say 1500uS, will it continuously rotate and this frequency will control the speed of rotation?

4

The frequency does NOT control the speed of rotation. The speed of rotation is controlled by the pulse width.

Typically: a square wave (50% duty cycle) is no rotation, nearly 0% duty cycle is full speed rotation in one direction, and nearly 100% duty cycle is full speed rotation in the opposite direction.

It is a similar thing with position servos. The frequency does NOT control the position. The position is controlled by the pulse width.

Typically: a square wave (50% duty cycle) is the center position, nearly 0% duty cycle is the position near one end, and nearly 100% duty cycle is the position near the other end.

The frequency is not critical. 500 Hz is often used. 1 KHz would be good also. The 1500 microseconds that was mentioned translates into about 667 Hz which is fine.

5

You may use either servo.write or servo.writeMicroseconds. It just depends upon whether you prefer a range of 0 through 180, or 1000 through 2000.

6

Thank you for your help guys.

Problem solved.