Arduino application

1.Software

Yu can download Arduino IDE from www.arduino.cc according to your PC's version and then install by youself.

2.Hardware

Data from（https://wiki.seeedstudio.com/XIAO_ESP32C3_Getting_Started/）

Seeed Studio XIAO ESP32C3 is an IoT mini development board based on the Espressif ESP32-C3 WiFi/Bluetooth dual-mode chip, featuring a 32-bit RISC-V CPU that delivers powerful computing performance with its efficient architecture.

Pinout diagram

Item	Seeed Studio XIAO ESP32C3	Seeeduino XIAO	Seeed XIAO RP2040	Seeed XIAO nRF52840	Seeed XIAO nRF52840 Sense
Processor	ESP32-C3 32-bit RISC-V @160MHz	SAMD21 M0+@48MHz	RP2040 Dual-core M0+@133Mhz	nRF52840 M4F@64MHz	nRF52840 M4F@64MHz
Wireless Connectivity	WiFi and Bluetooth 5 (BLE)	N/A	N/A	Bluetooth 5.0/BLE/NFC	Bluetooth 5.0/BLE/NFC
Memory	400KB SRAM, 4MB onboard Flash	32KB SRAM 256KB FLASH	264KB SRAM 2MB onboard Flash	256KB RAM, 1MB Flash 2MB onboard Flash	256KB RAM,1MB Flash 2MB onboard Flash
Built-in Sensors	N/A	N/A	N/A	N/A	6 DOF IMU (LSM6DS3TR-C), PDM Microphone
Interfaces	I2C/UART/SPI	I2C/UART/SPI	I2C/UART/SPI	I2C/UART/SPI	I2C/UART/SPI
PWM/Analog Pins	11/4	11/11	11/4	11/6	11/6
Onboard Buttons	Reset/ Boot Button	N/A	Reset/ Boot Button	Reset Button	Reset Button
Onboard LEDs	Charge LED	N/A	Full-color RGB/ 3-in-one LED	3-in-one LED/ Charge LED	3-in-one LED/ Charge LED
Battery Charge Chip	Built-in	N/A	N/A	BQ25101	BQ25101
Programming Languages	Arduino/ MicroPython	Arduino/ CircuitPython	Arduino/ MicroPython	Arduino/ CircuitPython	Arduino/ CircuitPython

3.Arduino Output

​Project Definition​​

This Arduino project demonstrates basic digital output control using the ​​Seeed Studio XIAO ESP32C3​​ development board. It creates a blinking LED effect through GPIO manipulation, serving as a fundamental example of hardware interaction in embedded systems. The project uses an external LED connected to pin D10 since the XIAO ESP32C3 lacks a built-in LED.

Wiring Diagram

• Connect LED cathode (shorter leg) to ​​GND​​.
• Connect LED anode (longer leg) to ​​D10​​ through a 220Ω current-limiting resistor
• Power the board via USB

Code Implementation

// define led according to pin diagram in article
const int led = D10; // there is no LED_BUILTIN available for the XIAO ESP32C3.

void setup() {
  // initialize digital pin led as an output
  pinMode(led, OUTPUT);
}

void loop() {
  digitalWrite(led, HIGH);   // turn the LED on 
  delay(1000);               // wait for a second
  digitalWrite(led, LOW);    // turn the LED off
  delay(1000);               // wait for a second
}

Expected Effect​​

The LED will alternate between ON and OFF states at 1-second intervals. This demonstrates:

• ​Digital Output Control​​: GPIO pin voltage switching between 0V (LOW) and 3.3V (HIGH)
• ​​Timing Functions​​: Using delay() for temporal control
• ​​Circuit Protection​​: Proper current limitation through resistor

4.Arduino Input

​Project Definition​​

This Arduino project implements an intelligent distance monitoring system using an ​​HC-SR04 ultrasonic sensor​​ and LED indicator. It continuously measures environmental distances and activates an LED (connected to D10) when objects exceed 200cm, demonstrating:

• Real-time distance measurement (0-400cm range)
• Threshold-based output control
• Serial data monitoring (count & distance values)

​​Circuit Diagram​​

​​Components Required:​​

• Xiao esp32c3
• HC-SR04 Ultrasonic Sensor
• LED + 220Ω resistor
• Breadboard & jumper wires

Code Implementation

#define TrigPin A0
#define EchoPin A1
int count = 0;
long duration;


void setup() {
  Serial.begin(115200);
  pinMode(TrigPin, OUTPUT);
  pinMode(EchoPin, INPUT);
  digitalWrite(TrigPin, LOW);
  delay(1);
  pinMode (D10, OUTPUT);

}

void loop() {
  Serial.println(count++);
  Serial.println(getDistance());
  Serial.println("");
  Serial.println("");
  delay(1000);
  int distance= getDistance();
  if (distance>200){
    digitalWrite(D10, HIGH);
  }
  else {
    digitalWrite(D10, LOW);
  }
}

long getDistance() {
  digitalWrite(TrigPin,LOW);
  delayMicroseconds(2);
  digitalWrite(TrigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(TrigPin,LOW);
  duration = pulseIn(EchoPin,HIGH);
  return duration * 0.34029 /2;
}

System Behavior​​

Expected Effects:

• ​Serial Output​​ (115200 baud): Cycle counter increments every second Real-time distance measurements in centimeters Example: Cycle: 42
  Distance: 215 cm
• ​LED Indication​​: Illuminates continuously when distance > 200cm Turns off when objects move within 200cm range
• ​Measurement Characteristics​​: Accuracy: ±3mm (within 100cm) Maximum detection: ~400cm Sampling rate: 1Hz
  

5.Homwork

​Project Definition​​

This Arduino project implements a simple ​​IoT Temperature Monitoring Station​​ that utilizes an DHT11 temperature and humidity sensor and an LCD display. It demonstrates:

Real-time temperature/humidity data acquisition (0-50°C ±2°C, 20-90% RH ±5%) Dual-unit temperature display (Celsius/Fahrenheit) Graphical user interface with color-coded parameters Error detection and visual alerts SPI communication protocol implementation

Wiring Diagram

Required Components:​​

XIAO ESP32C3 ILI9341 TFT LCD (240x320) DHT11 Temperature/Humidity Sensor Breadboard & jumper wires

Methods to Install Arduino Libraries​

Launch Arduino IDE

• Open the development environment (version 1.8.19+ recommended)

Access Library Manager

• Navigate to: Sketch > Include Library > Manage Libraries...

Search & Install

• Type library name in search bar (e.g., "Wire")
• Select desired version from dropdown
• Click "Install" (Internet required) Verification
• Installed libraries appear under: File > Examples > [Library Name]

Code Implementation

#include "SPI.h"
#include "Adafruit_GFX.h"
#include "Adafruit_ILI9341.h"
#include "DHT.h"

// LCD pin definitions
#define TFT_CLK D0
#define TFT_RST D1
#define TFT_MISO MISO
#define TFT_MOSI MOSI
#define TFT_DC D2
#define TFT_CS D3

// DHT sensor definitions
#define DHTPIN D7     // DHT sensor connected to pin D7
#define DHTTYPE DHT11 // Using DHT11 sensor

// LCD color definitions
#define ILI9341_BLACK       0x0000
#define ILI9341_WHITE       0xFFFF
#define ILI9341_GREEN       0x07E0
#define ILI9341_RED         0xF800
#define ILI9341_BLUE        0x001F
#define ILI9341_YELLOW      0xFFE0

// Initialize objects
Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC, TFT_MOSI, TFT_CLK, TFT_RST, TFT_MISO);
DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(9600);
  Serial.println("Temperature and Humidity Display");
  
  // Initialize LCD
  tft.begin();
  tft.setRotation(1); // Optional: adjust screen orientation (0-3)
  
  // Initialize DHT sensor
  dht.begin();
  
  // Display initial screen
  tft.fillScreen(ILI9341_BLACK);
  tft.setTextColor(ILI9341_WHITE);
  tft.setTextSize(2);
  tft.setCursor(20, 100);
  tft.println("Initializing...");
  delay(2000);
}

void loop() {
  // Read sensor data
  float humidity = dht.readHumidity();
  float tempC = dht.readTemperature();      // Celsius
  float tempF = dht.readTemperature(true);  // Fahrenheit
  
  // Check if data is valid
  if (isnan(humidity) || isnan(tempC) || isnan(tempF)) {
    displayError();
    delay(2000);
    return;
  }
  
  // Display data
  displayData(humidity, tempC, tempF);
  delay(2000);  // Update every 2 seconds
}

void displayData(float humidity, float tempC, float tempF) {
  // Clear screen
  tft.fillScreen(ILI9341_BLACK);
  
  // Set title
  tft.setTextColor(ILI9341_YELLOW);
  tft.setTextSize(3);
  tft.setCursor(20, 20);
  tft.println("Weather Station");
  
  // Display humidity
  tft.setTextColor(ILI9341_BLUE);
  tft.setTextSize(2);
  tft.setCursor(20, 70);
  tft.print("Humidity: ");
  tft.print(humidity);
  tft.println(" %");
  
  // Display Celsius temperature
  tft.setTextColor(ILI9341_RED);
  tft.setCursor(20, 100);
  tft.print("Temp: ");
  tft.print(tempC);
  tft.println(" *C");
  
  // Display Fahrenheit temperature
  tft.setTextColor(ILI9341_GREEN);
  tft.setCursor(20, 130);
  tft.print("Temp: ");
  tft.print(tempF);
  tft.println(" *F");
}

void displayError() {
  // Display error message
  tft.fillScreen(ILI9341_BLACK);
  tft.setTextColor(ILI9341_RED);
  tft.setTextSize(2);
  tft.setCursor(20, 100);
  tft.println("Sensor Error!");
  tft.setCursor(20, 130);
  tft.println("Check Connection");
}

Expected Effect​​

perational Effects:​​

​​Display Output​​: Yellow header "Weather Station" Blue humidity reading (0-100% RH) Red Celsius (0-50°C) / Green Fahrenheit Coordinated layout prevents screen tearing

​​Error Handling​​: Sensor Error!
Check Connection

​​Performance Metrics​​: Sampling Rate: 0.5Hz (conserves power) SPI Throughput: 15MHz (smooth rendering) Accuracy: ±2°C (temp), ±5% (humidity)