Introduction to Arduino

Overview of Arduino

• Arduino's naming is derived from an Italian bar in Ivrea, where the project's originators convened.
• The bar was named in honor of Arduin of Ivrea, an Italian historical figure.
• Today, Arduino is dedicated to creating boards for object sensing and control across digital and physical domains.

What is Arduino?

• Arduino is an open-source physical computing platform constructed around a microcontroller board.
• Consists of several parts, including microcontrollers for processing, onboard power for operational effectiveness, and USB ports for communication.
• Uses an Atmel Microcontroller that allows you to program.
• Includes an open-source Integrated Development Environment (IDE) to create interactive applications using varied sensor inputs and control outputs like lights, motors, and buzzers.
• Can work as a standalone or communicate with multiple computers over a network.
• Arduino is a tool to hobbyists and professionals in education, art, and engineering.

Arduino Board Designs

• Offers diverse board designs featuring various microprocessors and microcontrollers.
• Each board features analog and digital input/output pins, enabling compatibility with a wide range of expansion shields.

Arduino boards comparison

• ATmega328P, produced by Atmel, has the letter P for "PicoPower," and minimizes power consumption during sleep modes.
• Arduino Uno's recommended external power supply is 7V to 12V, but can handle 6V to 20V.
• Sticking to the 7V-12V range is recommended for safety.
• Voltages below 7V might cause instability, and above 12V may overheat the voltage regulator.
• A voltage regulator maintains a constant output voltage regardless of input conditions, ensuring stable voltage for sensitive electronic components.

Arduino Uno

• The Arduino Uno is built around the ATmega328P microcontroller.
• "Uno" means "one" in Italian, marks its release as version 1.0 of the Arduino Software (IDE).
• This was the first in the USB Arduino series, and it serves as a reference model.

Arduino Uno features

• 14 digital input/output pins, 6 analog input pins, and 8 power supply pins which have holes for 24-gauge wire.
• Digital I/O pins perform in binary form, recognizing 0V as "0" and 5V as "1".
• Arduino boards operate at 3.3V or 5V.
• Analog pins allow voltages between 0 and 5V for the microcontroller to interpret.
• They do not provide direct analog output, it has an analog-to-digital converter (ADC).
• In addition, typical output pins supply 5V and 3.3V, and the board has ground pins.
• 2 Microcontrollers: ATmega328 processor executes user-defined code and ATmega16U2 manages USB communication.
• ATmega16U2 has non-editable firmware for its specific function.

Code on a Microcontroller

• Primary Code types: application code and firmware.
• Application code refers to user-written code, is developed for specific application needs.
• Firmware is built into the microcontroller and supports USB interface and power management.

Firmware and Bootloaders

• Firmware is programmed circumventing the USB route or IDE.
• Firmware on a microcontroller is known as a bootloader.
• The bootloader enables rewriting flash memory and EEPROM, facilitating new application code.
• It can't program itself and needs In-Circuit Serial Programming to be programmed.

In-Circuit Serial Programming (ICSP)

• Special pins in the Arduino board offer a direct route to program the microcontroller.
• It modifies firmware, while application code updates are more common.
• Has two ICSP ports for the two processors on the Arduino board, and each processor has its own firmware.
• The distinction between firmware and application code depends on the perspective.

Arduino Schematics

• Schematics illustrate connections between hardware modules.
• Found on Arduino.cc, and valuable for customizing boards.
• Schematics components are physically present, but have a different layout.
• The ATmega16U2 appears bigger than ATmega328 on the schematics, although that's not reality.

Pulse Width Modulation (PWM)

• Technique generating analog results by digital means.
• Square wave signal switches between "on" and "off" state.
• Varying the on-state duration simulates voltages between the full "on" (5V) and "off" (0V) states.
• On-time duration: "pulse width" to modulate, and mimics steady voltage, controlling LED brightness, allowing smooth dimming and output control.
• Built-in PWM circuits is included on pins 3, 5, 6, 9, 10, and 11

PWM Commands

• analogWrite(pin, value) can be used to set a duty cycle, where value is between 0 and 255
• analogWrite(9, 128) sets a 50% duty cycle
• analogWrite(11, 64) writes a 25% duty cycle

Serial Communication

• Serial.begin() function sets up communication with the serial port.
• The serial port is a hardware interface for data transfer.
• Baud rate must match on sending and receiving devices.
• Baud rate is the rate that data is transmitted in bits per second (bps).
• Common baud rates include 9600, 115200, and 57600.