กระทู้ไมโครคอนโทรลเลอร์ ESP32 (EP.3) ESP32 กับ sensor ต่าง ๆ

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SH110X.h>
#include <DHT.h>

// OLED Configuration
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_ADDRESS 0x3C  // Common I2C address for these displays
#define I2C_SDA 40
#define I2C_SCL 42
Adafruit_SH1106G display = Adafruit_SH1106G(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// DHT22 Configuration
#define DHTPIN 5
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

// LDR Configuration
#define LDR_PIN 1

// HY-SRF05 Configuration
#define TRIG_PIN 7
#define ECHO_PIN 8

// Timing Variables (Non-blocking using millis)
unsigned long lastDHTRead = 0;
unsigned long lastLDRRead = 0;
unsigned long lastSonicRead = 0;

const long dhtInterval = 5000;   // 5 seconds
const long ldrInterval = 300;    // 300 ms
const long sonicInterval = 1000; // 1 second

// Global variables to hold last read values
float currentTemp = 0.0;
float lightPercent = 0.0;
float currentRange = 0.0;

void setup() {
  Serial.begin(115200);

  // Initialize Custom I2C pins for ESP32-S3
  Wire.begin(I2C_SDA, I2C_SCL);

  // Initialize OLED
  if (!display.begin(OLED_ADDRESS, true)) {
    Serial.println(F("SH1106 OLED initialization failed!"));
    for (;;);
  }
  
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SH110X_WHITE);
  display.display();

  // Initialize DHT
  dht.begin();

  // Initialize Ultrasonic Pins
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);

  // Configure ADC attenuation if needed for 0-3V range
  // By default, ESP32 Arduino Core 3.x configures ADC to 11dB (~0V - 3.3V)
  analogSetPinAttenuation(LDR_PIN, ADC_11db);
}

void loop() {
  unsigned long currentMillis = millis();
  bool needUpdateDisplay = false;

  // 1. Read DHT22 every 5 seconds
  if (currentMillis - lastDHTRead >= dhtInterval) {
    lastDHTRead = currentMillis;
    float t = dht.readTemperature();
    if (!isnan(t)) {
      currentTemp = t;
      needUpdateDisplay = true;
    }
  }

  // 2 & 3. Read LDR every 300 ms and map voltage
  if (currentMillis - lastLDRRead >= ldrInterval) {
    lastLDRRead = currentMillis;
    
    // Read raw ADC (ESP32-S3 has 12-bit ADC: 0 - 4095)
    int rawADC = analogRead(LDR_PIN);
    
    // Convert to Voltage (assuming 3.3V VREF)
    float voltage = (rawADC / 4095.0) * 3.3;
    
    // Map 1.0V - 3.0V to 0% - 100%
    if (voltage < 1.0) {
      lightPercent = 0.0;
    } else if (voltage > 3.0) {
      lightPercent = 100.0;
    } else {
      // Linear interpolation formula: (value - in_min) * (out_max - out_min) / (in_max - in_min) + out_min
      lightPercent = (voltage - 1.0) * (100.0 - 0.0) / (3.0 - 1.0) + 0.0;
    }
    needUpdateDisplay = true;
  }

  // 4. Read HY-SRF05 Ultrasonic every 1 second
  if (currentMillis - lastSonicRead >= sonicInterval) {
    lastSonicRead = currentMillis;
    
    // Trigger the sensor
    digitalWrite(TRIG_PIN, LOW);
    delayMicroseconds(2);
    digitalWrite(TRIG_PIN, HIGH);
    delayMicroseconds(10);
    digitalWrite(TRIG_PIN, LOW);
    
    // Read echo duration (travel time in microseconds)
    long duration = pulseIn(ECHO_PIN, HIGH, 30000); // 30ms timeout (~5 meters max)
    
    // Calculate distance in cm (Speed of sound is ~343 m/s or 0.0343 cm/us)
    if (duration > 0) {
      currentRange = (duration * 0.0343) / 2.0;
    } else {
      currentRange = -1.0; // Out of range / timeout indicator
    }
    needUpdateDisplay = true;
  }

  // Update OLED if any data has changed
  if (needUpdateDisplay) {
    updateOLED();
  }
}

void updateOLED() {
  display.clearDisplay();
  
  // Line 1: Temperature
  display.setCursor(0, 4);
  display.print("Temp: ");
  display.print(currentTemp, 1); // 1 decimal place
  display.print(" C");
  
  // Line 2: Light Level
  display.setCursor(0, 24);
  display.print("Light level = ");
  display.print(lightPercent, 1); // 1 decimal place
  display.print(" %");
  
  // Line 3: Range
  display.setCursor(0, 44);
  if (currentRange >= 0) {
    display.print("Range = ");
    display.print(currentRange, 1); // 1 decimal place
    display.print(" cm");
  } else {
    display.print("Range = Out of Bound");
  }
  
  display.display();
}