9. Input Devices

This week, I focused on input devices by reading a pushbutton signal from the microcontroller. I built and simulated the circuit in Circuit Designer, then verified the input-reading logic with Arduino code.

Assignment Goal

The goal of this assignment was to connect and read an input device in a microcontroller project. I used a button as the input source and used servo movement to visualize the reading result.

Circuit Design

I designed a simple test circuit with a pushbutton and a servo motor. The button is connected to pin D2 and the servo signal is connected to pin D5 of the XIAO ESP32S3.

• Microcontroller: XIAO ESP32S3
• Input: Pushbutton on D2
• Output: Servo motor on D5
• Power: 5V and GND from the controller

Programming and Test

I wrote a simple Arduino sketch to read the button state and control the servo position. When the button is pressed, the servo rotates to 10 degrees; otherwise, it returns to 0 degrees.

/*
 * This Arduino sketch controls a servo motor using a pushbutton.
 * When the button on D2 is pressed, the servo on D5 rotates by 10 degrees.
 */

#include <Servo.h>

Servo myServo;

const int buttonPin = D2;
const int servoPin = D5;

int buttonState = 0;

void setup() {
  pinMode(buttonPin, INPUT);
  myServo.attach(servoPin);
  myServo.write(0);
}

void loop() {
  buttonState = digitalRead(buttonPin);

  if (buttonState == HIGH) {
    myServo.write(10);
    delay(500);
  } else {
    myServo.write(0);
  }
}
        

What I Learned

• How to connect and read a pushbutton as a digital input
• How digital input can trigger physical movement as feedback
• How to verify behavior through simulation before fabrication