360 continues servo

Video Tutorial

you can watch this video tutorial

Hardware Required

About this project

Introduction to Continuous Servo Motor

The standard servo motor is a motor that can rotate between 0° and 180°. and you can review our tutorial about it here.

Its internal gearing provides a high torque power pack in a small and inexpensive package.

That combination of small size and large torque also make servos attractive to use as replacements for standard DC motors in the design of small devices like tiny toys and robots. This prompted several people to modify standard analog servos by removing the potentiometer to allow the servo to spin a full 360 degrees.

Manufactures got the message and now offer “continuous rotation servo motors”, essentially servos with the servomechanism disengaged.

In a continuous rotation servo motor the speed and direction of the shaft rotation is controlled by the same PWM signal that is used in a conventional analog servo motor.

Servo Motor Pinout

The servo motor has three pins:

• GND pin:(brown or black) connects this pin to GND (0V)
• VCC pin: (red) connects this pin to VCC (5V)
• Signal pin: (yellow or orange) receives the PWM control signal from an ESP32's pin.

How Servo Motor Works

After connecting VCC pin and GND pin to 5V and 0V, respectively, we can control the servo motor by generating proper PWM signal to signal pin.

The direction is determined by the width of PWM signal.

The direction is determined as follows:

• If PWM's width = WIDTH_MIN, the servo motor rotates at full speed counter-clockwise.
• If PWM's width = WIDTH_MAX, the servo motor rotates at full speed clockwise.
• If PWM's width is between WIDTH_MIN and WIDTH_MAX, the servo motor rotates slower until it STOP then rotates in the opposite direction.

Introduction to Button

please review our tutorial about Button

ESP32 - Servo Motor

We can control the servo motor by connecting the servo motor's signal pin to an ESP32's pin, and programming to generate PWM on the ESP32's pin.

Thanks to Arduino Servo library, controlling servo motor is a piece of cake. We even do NOT need to know how servo motor works. We also do NOT need to know how to generate PWM signal. We JUST need to learn how to use the library.

• Click here to download the ESP32_Arduino_Servo_Library. You should have a .zip folder in your Downloads folder
• Unzip the .zip folder and you should get ESP32-Arduino-Servo-Library-Master folder
• Rename your folder from ESP32-Arduino-Servo-Library-Master to ESP32_Arduino_Servo_Library
• Move the ESP32_Arduino_Servo_Library folder to your Arduino IDE installation libraries folder
• Finally, re-open your Arduino IDE

How To Program For Servo Motor

• Include the library:

#include <Servo.h> 

• Declare a Servo object:

Servo myServo;

• If you control more than one servo motors, you just need to declare more Servo objects:

Servo myServo1;
Servo myServo2;

• Set the control pin of Arduino, which connects to the signal pin of the servo motor. For example, pin 9:

myServo.attach(9);

• Lastly, rotate the servo motor to the desired direction. For example, (0) to rotate at ccw:

myServo.write(0);

• another example, (90) to STOP:

myServo.write(90);

Wiring Diagram

Schematic Diagram

Image is developed using Fritzing. Click to enlarge image

Breadboard Connections

Image is developed using Fritzing. Click to enlarge image

click to see ESP32 pin out

ESP32 Code

#include <Servo.h>

Servo myservo;  // create servo object to control a servo


void setup() {
  myservo.attach(21);  // attaches the servo on pin 4 to the servo object
  pinMode(4,INPUT_PULLUP);
  pinMode(16,INPUT_PULLUP);
  pinMode(17,INPUT_PULLUP);
}

void loop() {
  if(digitalRead(4)==LOW)
  {
    myservo.write(10);              // tell servo to rotate at ccw
    delay(15);                      // waits 15ms for the servo to reach the position
  }

  if(digitalRead(16)==LOW)
  {
    myservo.write(90);              // tell servo to STOP
    delay(15);                      // waits 15ms for the servo to reach the position   
  }

  if(digitalRead(17)==LOW)
  {
    myservo.write(170);              // tell servo to rotate at cw
    delay(15);                      // waits 15ms for the servo to reach the position   
  }

}          

Book Tutorial

We are considering to make the book tutorials. If you think the book tutorials are essential, you can download it. download book

See Also

• ESP32 - Button - Debounce
• ESP32 - Button - Long Press Short Press
• ESP32 - Button Toggle LED

References

• Arduino IDE
• ESP32