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Controlling a Servo with Push Buttons Using Arduino

In this tutorial, we will learn how to control a servo motor using two push buttons, one for moving the servo to the left and another for moving it to the right. When you press the right button, the servo will move by 10 degrees to the right, and when you press the left button, it will move by the same amount to the left. If you hold a button down, the servo will continue to move in that direction until you release it.

This project is a great way to understand how to interface buttons with a servo motor using Arduino. We will cover the necessary hardware components, wiring instructions, and the code needed to make it all work. For a clearer understanding, you can refer to the video accompanying this tutorial (in video at 01:00).

Hardware Explained

For this project, you will need an Arduino board, a servo motor, and two push buttons. The servo motor is responsible for the movement, while the push buttons act as inputs to control the direction of that movement. The Arduino processes these inputs and sends the appropriate signals to the servo.

The servo motor operates based on pulse-width modulation (PWM) signals. By sending different pulse widths, you can control the angle of the servo. The push buttons will be connected to digital input pins on the Arduino, and we will use internal pull-up resistors to simplify the wiring.

Datasheet Details

• Ensure the servo is rated for your supply voltage.
• Use appropriate heat sinking if operating at high currents.
• Connect buttons to ground with pull-up configuration.
• Debounce your buttons if experiencing erratic behavior.
• Monitor the serial output for debugging.

Wiring Instructions

To wire the components, start by connecting the servo motor. Connect the red wire of the servo to the 5V pin on the Arduino, the black wire to the GND pin, and the yellow or white signal wire to pin 9 on the Arduino. This pin will control the position of the servo.

Next, wire the push buttons. Connect one terminal of the right button to pin 2 and the other terminal to ground. For the left button, connect one terminal to pin 12 and the other terminal to ground as well. This setup allows the internal pull-up resistors to keep the pins high when the buttons are not pressed.

Code Examples & Walkthrough

Let's begin with the code for controlling the servo with a single push button. The code initializes the servo object and sets an initial angle. Here's a short excerpt:

int angle = 90;    // initial angle for servo
int angleStep = 10; // step size for movement

In this snippet, angle represents the current position of the servo, while angleStep defines how much the servo moves with each button press. This code is essential for tracking the servo's position.

Next, we have the setup function where we attach the servo and configure the input pins:

void setup() {
  Serial.begin(9600);          // setup serial
  myservo.attach(9);  // attaches the servo on pin 9
  pinMode(2, INPUT_PULLUP); // configure button pin
}

In the setup, we initialize the serial monitor and attach the servo to pin 9. The button on pin 2 is set as an input with a pull-up resistor, which simplifies wiring and avoids the need for external resistors.

Finally, we look at the loop function that handles the button press:

while(digitalRead(2) == LOW) {
  angle = angle + angleStep; // increment angle
  myservo.write(angle); // move servo
}

This loop continuously checks if the button is pressed. When it's pressed, the angle increases by the defined step, and the servo moves accordingly. It's crucial to ensure that the angle stays within bounds (0 to 180 degrees) to prevent damage to the servo.

Demonstration / What to Expect

When you press the right button, the servo should move to the right in increments of 10 degrees until it reaches the maximum of 180 degrees. Similarly, pressing the left button will move it to the left. If you hold down a button, the servo will keep moving in that direction until you release the button (in video at 01:00).

Common pitfalls include wiring issues, such as incorrect connections or floating inputs. Always ensure that your connections are secure and that you are using the correct pins as specified in the code.

图像

Control Servo with single push button with Arduino

SG90_servo_motor-1

SG90_servo_motor-0

Arduino wriing for Sevo motor with 2 push buttons

Control Servo with single push button with Arduino

SG90_servo_motor-1

SG90_servo_motor-0

Arduino wriing for Sevo motor with 2 push buttons