arduino

Overview

• Arduino: A board with a microcontroller, typically an ATmega328.

• PWM Pins (~): Indicated by ~ on the Arduino pins, capable of Pulse Width Modulation (PWM).

  • PWM: Allows values other than on and off by precisely controlling frequency.
  • Used to simulate analog output using analogWrite(), but still digital in nature.

• Analog Pins: Real analog input pins are available on the Arduino.

Pin Information

• Pin 13: Same as the built-in LED pin.
• TX and RX LEDs: Indicate when the Arduino is transmitting (TX) or receiving (RX) data.
• Reset Button: Resets the code but does not clear the memory.

Serial Communication

• Serial.begin(9600);: Initializes serial communication at 9600 baud rate.
• Serial.print();: Prints data to the serial monitor without a newline.
• Serial.println();: Prints data to the serial monitor with a newline.

Logic Levels

• HIGH: Equivalent to true or 1.
• LOW: Equivalent to false or 0.

Variables

• Use static int for variables to persist their value across function calls instead of declaring global variables.

ADC (Analog-to-Digital Conversion)

• Converts voltage values from 0V to 5V into digital values ranging from 0 to 1023.

Key Functions

Digital I/O

• digitalRead(pin): Reads the state (HIGH or LOW) of a digital pin.
• digitalWrite(pin, value): Sets a digital pin to HIGH or LOW.

Analog I/O

• analogRead(pin): Reads the value from an analog pin (0 to 1023).
• analogWrite(pin, value): Outputs PWM signal (0 to 255) for controlling LED brightness or motor speed.
  • Can only be used with PWM pins (~).

PWM Details

• Duty Cycle: Fraction of the period during which the voltage is HIGH.
  • analogWrite(0) → 0% duty cycle
  • analogWrite(64) → 25% duty cycle
  • analogWrite(127) → 50% duty cycle
  • analogWrite(191) → 75% duty cycle
  • analogWrite(255) → 100% duty cycle
• PWM is used to control things like LED brightness and motor speed.