Exercise 2: Arduino

1. Learning Open Source Hardware - Arduino

Source: Arduino UNO R4 WiFi Development Board Detailed Explanation http://xhslink.com/o/8dtNOFFrhe 这篇内容在【小红书】候着你~

Arduino is an open-source electronic prototyping platform that includes hardware (various models of Arduino development boards) and software (Arduino IDE). Its core advantages are:

• Open Source & Free: Hardware design, software code, and schematics are all open source, allowing free modification and secondary development
• Low Barrier to Entry: Uses simplified C/C++ syntax, no need to delve into microcontroller basics, beginners can get started quickly
• Strong Ecosystem: Massive open-source libraries, sensor modules, and project cases worldwide, capable of achieving almost all electronic creativity

Common Application Scenarios:

• Teaching & Learning: Programming basics (C/C++, logic training), electronics basics (sensors, LEDs, motors, circuits), school courses (information technology, general technology, innovation competitions), graduation projects/course designs (simple smart projects)
• Smart Home: Smart lighting (voice-controlled lights, motion sensor lights, RGB ambient lights), environmental monitoring (temperature/humidity, air quality, light, PM2.5 detection), automatic control (automatic watering, automatic fish feeding, smart curtains), security alerts (door magnetic alarm, infrared intrusion alarm, water leak detection)
• Interactive Art & Installations: Interactive light shows (music rhythm lights, body-sensing light and shadow), new media art installations (touch sensing, sound interaction), stage/exhibition effects (automatically triggered lights, smoke, mechanical actions)
• DIY Electronics: Electronic clocks, thermometers, hygrometers, simple oscilloscopes, Bluetooth/infrared remote switches, wireless doorbells, simple 3D printers, plotters, laser engraver controllers
• Industrial/Lab Applications: Data collection (temperature, pressure, RPM sensor recording), simple automation control (small motor start/stop, solenoid valve control), IoT nodes (upload data to mobile or cloud via WiFi/Bluetooth)

1. Arduino IDE

(1) Introduction

Arduino IDE is an integrated development environment for writing, uploading, and debugging programs based on the Arduino platform. It's an open-source tool that runs on Windows, Mac OS X, and Linux systems. Arduino IDE uses C/C++ language with a simple graphical interface, making it easy for users to write programs. Through this interface, users can easily access various Arduino board libraries and example programs, and quickly write and test their own programs.

Arduino IDE includes a code editor, compiler, uploader, and serial monitor for debugging and viewing program output. Additionally, it supports multiple platforms and programming languages, and can integrate with other open-source tools. Using Arduino IDE, users can develop various Arduino projects such as LED control, sensor reading, robot control, etc. Its ease of use and powerful features make it one of the preferred tools for many makers and engineers.

References:

• 零基础学Arduino-2《 IDE 界面功能介绍》 - View on Xiaohongshu (Little Red Book)
• 📒・Arduino入门・IDE界面介绍 - View on Xiaohongshu (Little Red Book)

(2) Coding Methods

• Structure: An Arduino program consists of two essential functions: setup() and loop(). The setup() function runs only once at program startup for initialization settings, such as pin mode definition and serial port initialization. The loop() function runs in a loop after the setup() function executes, controlling the main program logic.
• Comments: Using comments improves code readability. You can use double slashes (//) to add single-line comments, or use slash-asterisk (/* */) to add multi-line comments.
• Variables: In Arduino, you can declare and use various variables such as integers (int), floating-point numbers (float), characters (char), and booleans (boolean). Variable names must start with a letter and can contain letters, numbers, and underscores.
• Pin Operations: Arduino's core is interacting with external devices, usually through pins for input and output. Use pinMode() to set pin mode as input or output, digitalRead() to read pin state, and digitalWrite() to set pin to HIGH or LOW.
• Functions: You can create custom functions to organize code and reuse specific functionality. Functions consist of function name, parameter list, and function body. Execute functions by calling the function name and passing parameters.
• Libraries: Arduino IDE has extensive library support to easily extend its functionality. You can import required libraries using #include directive and use library-provided functions and classes to implement specific features. For example, Servo library for servo control, Wire library for I2C communication, etc.
• Serial Communication: Arduino boards typically have a serial port. You can use the Serial object for serial communication with computers or other devices. Use Serial.begin() to initialize serial port, and Serial.print() and Serial.println() to send data to serial port.

(3) Hardware Connection

When using Arduino IDE, hardware connection is very important as it involves physical connections with the Arduino board and external components. Here are the general hardware connection methods when using Arduino IDE:

• Connect Arduino Board: First, connect your Arduino board to the computer via USB cable. This allows you to upload programs to the Arduino board and perform serial communication with it.
• Connect External Circuits: If your project involves external circuits or sensors, you need to connect them to the Arduino board. Typically, this involves using jumper wires to connect sensor or module pins to digital or analog pins on the Arduino board. Ensure correct connection of power and ground pins, as well as necessary signal lines.
• Power Supply: If external components require additional power supply, such as motors, servos, or high-power LEDs, you may need to provide external power instead of drawing directly from the Arduino board. This can be achieved through external batteries, power adapters, or other power modules.
• Upload Program: After writing and debugging your program in Arduino IDE, upload it to the Arduino board via USB cable. Ensure that before uploading, the Arduino board is correctly connected to the computer and the correct board type and serial port are selected.
• Debugging and Testing: Once the program is successfully uploaded, you can use the serial monitor to view program output for debugging and testing. The serial monitor displays information output using Serial.print() and Serial.println(), helping to understand program execution status.

Running Light Program Execution

(1) Physical Connection Method

1. Required Materials: Arduino development board, LED lights (quantity according to your needs), resistors (one per LED, determine resistance value based on selected LED characteristics), jumper wires or breadboard for connection
2. Connect Circuit: Connect each LED's anode (long pin) to Arduino's digital output pins. Connect each LED's cathode (short pin) to ground (GND) through a resistor.

(2) Program Execution Method

Writing the Program

• Create a new sketch in Arduino Integrated Development Environment (IDE).
• At the beginning of the program, define the LED pins to be controlled.
• Use loops to turn LEDs on and off one by one to achieve the running light effect.
• You can set delay intervals to control the speed of the running light.

I. Hardware List

• Arduino Uno R4 Minima/WiFi
• HC-SR04 Ultrasonic Module
• 4 LED lights + 220Ω current-limiting resistors ×4
• Breadboard, jumper wires

II. Circuit Wiring Diagram

1. HC-SR04 Ultrasonic Wiring

2. Running Light LED Wiring (Common Cathode, Negative Terminal Connected to Resistor)

• LED1 → D3 + 220Ω resistor → GND
• LED2 → D4 + 220Ω resistor → GND
• LED3 → D5 + 220Ω resistor → GND
• LED4 → D6 + 220Ω resistor → GND

Using Ultrasonic Sensor to Complete Running Light Illumination

Implementation Code:

// Ultrasonic pin definitions
const int trigPin = 9;
const int echoPin = 10;
// LED running light pin array
int ledPins[] = {3,4,5,6};
int ledNum = sizeof(ledPins)/sizeof(ledPins[0]);
long distance;
long duration;

void setup() {
  Serial.begin(9600);
  // Ultrasonic pin modes
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  // Set all LEDs as output
  for(int i=0; i<ledNum; i++){
    pinMode(ledPins[i], OUTPUT);
    digitalWrite(ledPins[i], LOW); // Initial light off
  }
}

// Get ultrasonic distance function
long getDistance(){
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;
  return distance;
}

void loop() {
  distance = getDistance();
  Serial.print("距离：");
  Serial.print(distance);
  Serial.println(" cm");

  // Trigger running light when less than 30cm
  if(distance < 30){
    // Forward running
    for(int i=0; i<ledNum; i++){
      digitalWrite(ledPins[i], HIGH);
      delay(150);
      digitalWrite(ledPins[i], LOW);
    }
    // Reverse return flow (optional, comment out to keep only unidirectional running)
    for(int i=ledNum-2; i>0; i--){
      digitalWrite(ledPins[i], HIGH);
      delay(150);
      digitalWrite(ledPins[i], LOW);
    }
  }else{
    // No object nearby, all off
    for(int i=0; i<ledNum; i++){
      digitalWrite(ledPins[i], LOW);
    }
  }
  delay(100);
}

4. Case Studies

Case 1: "Emotion Aid" Project

Case Link: https://blog.arduino.cc/2023/05/19/the-emotion-aid-is-a-wearable-device-that-communicates-the-users-emotions/#respond

• Core Objective: Help people with communication barriers (especially autism spectrum) convey their emotional states to the outside world using devices instead of body language
• Hardware Architecture: Arduino Uno Rev3 master controller + capacitive humidity sensor (EDA/GSR) + temperature sensor + pulse sensor + 9V battery power supply
• Output Method: Drive a fan-like device through small servos, changing its shape to express emotions through intuitive physical "fanning" motions

Case 2: UESTC Professor Xu Peng's Team - "Wireless Brain Function Assessment System" and "Autism Precision Neuromodulation Technology"

Case Link: https://www.new1.uestc.edu.cn/?n=UestcNews.Front.DocumentV2.ArticlePage&Id=96164

• Core Objective: Provide objective, quantitative auxiliary diagnosis and precise intervention for autism, benefiting over 3,000 children domestically and internationally.
• Hardware Architecture: Based on wireless dry-electrode EEG cap (non-invasive) and targeted transcranial magnetic stimulation device, no conductive gel required.
• Core Technology: Auxiliary diagnosis uses AI algorithms integrating deep learning and transfer learning to identify brain network abnormalities (>90% accuracy); intervention precisely locates superficial nodes to indirectly regulate deep brain regions.

Summary

Through this exercise, we learned:

• The core concepts and application scenarios of Arduino open-source hardware platform
• Arduino IDE usage, coding methods, and hardware connection techniques
• How to write and upload running light programs controlled by ultrasonic sensors
• Analyzed two real-world cases applying Arduino technology to assist autistic individuals
• Understanding both innovative solutions and existing challenges in assistive technology