Upgraded my filament dryer - Ventilation, WIFI, Control Humidity, Live Data

I upgraded my Sunlu S1 Plus filament dryer. Now I can control the ventilation to exhaust humid air based on readings from a humidity sensor which are visible with a dashboard that accessible through WIFI.

Arduino Codes:

I2C Scanner

#include <Wire.h>

void setup() {
  Wire.begin(4, 5); // SDA = GPIO4, SCL = GPIO5
  Serial.begin(115200);
  while (!Serial);
  Serial.println("\nI2C Scanner");
}

void loop() {
  byte error, address;
  int nDevices = 0;

  for (address = 1; address < 127; address++) {
    Wire.beginTransmission(address);
    error = Wire.endTransmission();
    if (error == 0) {
      Serial.print("I2C device found at address 0x");
      if (address < 16) Serial.print("0");
      Serial.println(address, HEX);
      nDevices++;
    }
  }
  if (nDevices == 0) Serial.println("No I2C devices found\n");
  delay(2000);
}

#include <Wire.h>

void setup() {

Wire.begin(4, 5); // SDA = GPIO4, SCL = GPIO5

Serial.begin(115200);

while (!Serial);

Serial.println("\nI2C Scanner");

}

void loop() {

byte error, address;

int nDevices = 0;

for (address = 1; address < 127; address++) {

Wire.beginTransmission(address);

error = Wire.endTransmission();

if (error == 0) {

Serial.print("I2C device found at address 0x");

if (address < 16) Serial.print("0");

Serial.println(address, HEX);

nDevices++;

}

if (nDevices == 0) Serial.println("No I2C devices found\n");

delay(2000);

}

Fan Test

// NodeMCU Axial Fan Relay Control via GPIO14 (D5)
// Send "on" to turn relay/fan ON, "off" to turn relay/fan OFF

const int relayPin = 14; // GPIO14 (D5) controls relay for axial fan
String inputString = ""; // String to hold incoming data
boolean stringComplete = false; // Flag to indicate string is complete

void setup() {
  // Initialize serial communication at 9600 baud
  Serial.begin(9600);
  
  // Initialize GPIO14 (D5) as output for relay control
  pinMode(relayPin, OUTPUT);
  
  // Start with fan off (relay open)
  digitalWrite(relayPin, LOW);
  
  // Print startup message
  Serial.println("NodeMCU Axial Fan Relay Control Ready");
  Serial.println("Send 'on' to turn fan ON");
  Serial.println("Send 'off' to turn fan OFF");
  Serial.println("------------------------");
}

void loop() {
  // Check if serial data is available
  if (Serial.available()) {
    // Read the incoming string
    inputString = Serial.readString();
    
    // Remove any whitespace/newline characters
    inputString.trim();
    
    // Convert to lowercase for easier comparison
    inputString.toLowerCase();
    
    // Check the command and control relay/fan
    if (inputString == "on") {
      digitalWrite(relayPin, HIGH);
      Serial.println("Axial fan turned ON (relay activated)");
    }
    else if (inputString == "off") {
      digitalWrite(relayPin, LOW);
      Serial.println("Axial fan turned OFF (relay deactivated)");
    }
    else {
      Serial.println("Invalid command. Use 'on' or 'off'");
    }
    
    // Clear the string for next input
    inputString = "";
  }
  
  // Small delay to prevent excessive loop iterations
  delay(100);
}

// NodeMCU Axial Fan Relay Control via GPIO14 (D5)

// Send "on" to turn relay/fan ON, "off" to turn relay/fan OFF

const int relayPin = 14; // GPIO14 (D5) controls relay for axial fan

String inputString = ""; // String to hold incoming data

boolean stringComplete = false; // Flag to indicate string is complete

void setup() {

// Initialize serial communication at 9600 baud

Serial.begin(9600);

// Initialize GPIO14 (D5) as output for relay control

pinMode(relayPin, OUTPUT);

// Start with fan off (relay open)

digitalWrite(relayPin, LOW);

// Print startup message

Serial.println("NodeMCU Axial Fan Relay Control Ready");

Serial.println("Send 'on' to turn fan ON");

Serial.println("Send 'off' to turn fan OFF");

Serial.println("------------------------");

}

void loop() {

// Check if serial data is available

if (Serial.available()) {

// Read the incoming string

inputString = Serial.readString();

// Remove any whitespace/newline characters

inputString.trim();

// Convert to lowercase for easier comparison

inputString.toLowerCase();

// Check the command and control relay/fan

if (inputString == "on") {

digitalWrite(relayPin, HIGH);

Serial.println("Axial fan turned ON (relay activated)");

}

else if (inputString == "off") {

digitalWrite(relayPin, LOW);

Serial.println("Axial fan turned OFF (relay deactivated)");

}

else {

Serial.println("Invalid command. Use 'on' or 'off'");

}

// Clear the string for next input

inputString = "";

}

// Small delay to prevent excessive loop iterations

delay(100);

}

Main Code for Dryer Control

#include <Wire.h>
#include <SPI.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BME280.h>
#include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>

const char* ssid = "Francesca";
const char* password = "DSR*5167248";

// Fan control pin (GPIO14 = D5)
const int FAN_RELAY_PIN = 14;  // D5 on NodeMCU

Adafruit_BME280 bme;
ESP8266WebServer server(80);

float temperature = 0.0;
float humidity = 0.0;
float dewPoint = 0.0;
float initialDewPoint = 0.0;
bool fanState = false;

// Variables for initial dew point capture
bool initialReadingTaken = false;

// Timing variables
unsigned long dryingStartTime = 0;
unsigned long lastFanDischargeTime = 0;
unsigned long fanStartTime = 0;
bool fanRunning = false;
const unsigned long FAN_RUN_DURATION = 120000; // 2 minutes in milliseconds

// Fan level tracking
int lastTriggeredLevel = 0; // 0 means no discharge yet
int currentCycleStartLevel = 1; // For subsequent cycles
int fanDischargeCount = 0;

// Last fan trigger data
float lastTriggerTemperature = 0.0;
float lastTriggerHumidity = 0.0;
float lastTriggerDewPoint = 0.0;

// Lookup table for initial fan discharge
struct FanLevel {
  int minutes;
  float dewPoint;
};

const FanLevel fanLevels[] = {
  {20, 45.0},   // Level 1
  {40, 42.5},   // Level 2
  {60, 40.0},   // Level 3
  {70, 37.5},   // Level 4
  {80, 35.0},   // Level 5
  {90, 32.5},  // Level 6
  {100, 30.0},  // Level 7
  {110, 29.0},  // Level 8
  {120, 28.0},  // Level 9
  {130, 27.0},  // Level 10
  {140, 26.0},  // Level 11
  {150, 25.0}   // Level 12
};

const int NUM_LEVELS = 12;
const int SUBSEQUENT_MINUTES[] = {20, 40, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150};

// Magnus formula to calculate dew point
float calculateDewPoint(float tempC, float hum) {
  const float a = 17.27;
  const float b = 237.7;
  float alpha = ((a * tempC) / (b + tempC)) + log(hum / 100.0);
  return (b * alpha) / (a - alpha);
}

// Get current elapsed time in minutes since start or last discharge
unsigned long getElapsedMinutes(bool sinceLastDischarge = false) {
  unsigned long referenceTime = sinceLastDischarge ? lastFanDischargeTime : dryingStartTime;
  return (millis() - referenceTime) / 60000;
}

// Control the fan based on sophisticated timing and dew point logic
void controlFan() {
  // Capture initial dew point from first reading
  if (!initialReadingTaken) {
    initialDewPoint = dewPoint;
    initialReadingTaken = true;
    Serial.println("=== Initial reading captured! ===");
    Serial.print("Room starting dew point: ");
    Serial.print(initialDewPoint, 1);
    Serial.println(" deg C");
    Serial.println("Fan control system is now active.");
  }

  // If fan is currently running, check if 2 minutes have elapsed
  if (fanRunning) {
    if (millis() - fanStartTime >= FAN_RUN_DURATION) {
      // Stop the fan
      digitalWrite(FAN_RELAY_PIN, LOW);
      fanState = false;
      fanRunning = false;
      lastFanDischargeTime = millis();
      fanDischargeCount++;
      
      Serial.println("Fan 2-minute cycle complete - Fan turned OFF");
      Serial.print("Total fan discharges: ");
      Serial.println(fanDischargeCount);
      
      // Set up for next cycle
      currentCycleStartLevel = lastTriggeredLevel;
    }
    return; // Don't check trigger conditions while fan is running
  }

  unsigned long elapsedMinutes;
  bool isFirstCycle = (fanDischargeCount == 0);
  
  if (isFirstCycle) {
    // First cycle - use original table timing from drying start
    elapsedMinutes = getElapsedMinutes(false);
    
    // Check each level in the original table
    for (int level = 0; level < NUM_LEVELS; level++) {
      if (elapsedMinutes >= fanLevels[level].minutes && dewPoint >= fanLevels[level].dewPoint) {
        // Trigger fan
        digitalWrite(FAN_RELAY_PIN, HIGH);
        fanState = true;
        fanRunning = true;
        fanStartTime = millis();
        lastTriggeredLevel = level + 1; // Store as 1-based level
        
        // Store trigger conditions
        lastTriggerTemperature = temperature;
        lastTriggerHumidity = humidity;
        lastTriggerDewPoint = dewPoint;
        
        Serial.print("First fan discharge triggered at Level ");
        Serial.print(lastTriggeredLevel);
        Serial.print(" - Elapsed: ");
        Serial.print(elapsedMinutes);
        Serial.print(" min, Dew Point: ");
        Serial.print(dewPoint, 1);
        Serial.println(" deg C - Fan ON for 2 minutes");
        return;
      }
    }
  } else {
    // Subsequent cycles - use modified timing from last discharge
    elapsedMinutes = getElapsedMinutes(true);
    
    // Check subsequent levels starting from where we left off
    for (int i = 0; i < NUM_LEVELS; i++) {
      int currentLevelIndex = (currentCycleStartLevel - 1) + i; // Convert to 0-based and offset
      
      if (currentLevelIndex >= NUM_LEVELS) break; // Don't go beyond table
      
      if (elapsedMinutes >= SUBSEQUENT_MINUTES[i] && dewPoint >= fanLevels[currentLevelIndex].dewPoint) {
        // Trigger fan
        digitalWrite(FAN_RELAY_PIN, HIGH);
        fanState = true;
        fanRunning = true;
        fanStartTime = millis();
        lastTriggeredLevel = currentLevelIndex + 1; // Store as 1-based level
        
        // Store trigger conditions
        lastTriggerTemperature = temperature;
        lastTriggerHumidity = humidity;
        lastTriggerDewPoint = dewPoint;
        
        Serial.print("Subsequent fan discharge triggered at Level ");
        Serial.print(lastTriggeredLevel);
        Serial.print(" - Elapsed since last discharge: ");
        Serial.print(elapsedMinutes);
        Serial.print(" min, Dew Point: ");
        Serial.print(dewPoint, 1);
        Serial.println(" deg C - Fan ON for 2 minutes");
        return;
      }
    }
  }
}

// Send formatted floats with 1 decimal place
String getDataJson() {
  unsigned long totalElapsed = getElapsedMinutes(false);
  unsigned long sinceLastDischarge = fanDischargeCount > 0 ? getElapsedMinutes(true) : 0;
  
  // Convert total elapsed to hours and minutes
  int totalHours = totalElapsed / 60;
  int totalMinutes = totalElapsed % 60;
  
  String json = "{";
  json += "\"temperature\": " + String(temperature, 1) + ",";
  json += "\"humidity\": " + String(humidity, 1) + ",";
  json += "\"dewpoint\": " + String(dewPoint, 1) + ",";
  json += "\"fanState\": " + String(fanState ? "true" : "false") + ",";
  json += "\"fanRunning\": " + String(fanRunning ? "true" : "false") + ",";
  json += "\"totalElapsed\": " + String(totalElapsed) + ",";
  json += "\"totalHours\": " + String(totalHours) + ",";
  json += "\"totalMinutes\": " + String(totalMinutes) + ",";
  json += "\"sinceLastDischarge\": " + String(sinceLastDischarge) + ",";
  json += "\"lastTriggeredLevel\": " + String(lastTriggeredLevel) + ",";
  json += "\"fanDischargeCount\": " + String(fanDischargeCount) + ",";
  json += "\"lastTriggerTemperature\": " + String(lastTriggerTemperature, 1) + ",";
  json += "\"lastTriggerHumidity\": " + String(lastTriggerHumidity, 1) + ",";
  json += "\"lastTriggerDewPoint\": " + String(lastTriggerDewPoint, 1) + ",";
  json += "\"initialDewPoint\": " + String(initialDewPoint, 1) + ",";
  json += "\"systemReady\": " + String(initialReadingTaken ? "true" : "false");
  json += "}";
  return json;
}

void handleRoot() {
  String html = R"rawliteral(
  <!DOCTYPE html>
  <html>
  <head>
    <title>BME280 Dryer Control System</title>
    <script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
    <style>
      body { font-family: Arial; text-align: center; margin: 0; padding: 0; background-color: #f5f5f5; }
      .header { background-color: #2c3e50; color: white; padding: 15px; }
      .status-grid {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
        gap: 15px;
        padding: 20px;
        max-width: 1200px;
        margin: 0 auto;
      }
      .status-card {
        background: white;
        border-radius: 8px;
        padding: 15px;
        box-shadow: 0 2px 4px rgba(0,0,0,0.1);
      }
      .status-title { font-weight: bold; color: #2c3e50; margin-bottom: 5px; }
      .status-value { font-size: 1.2em; color: #e74c3c; }
      .fan-status { font-weight: bold; font-size: 1.3em; }
      .fan-on { color: #e74c3c; }
      .fan-off { color: #27ae60; }
      .initializing { color: #f39c12; }
      .chart-container {
        display: flex;
        justify-content: space-around;
        align-items: center;
        width: 100%;
        background: white;
        margin: 20px auto;
        padding: 20px;
        border-radius: 8px;
        box-shadow: 0 2px 4px rgba(0,0,0,0.1);
        max-width: 1200px;
      }
      .chart-box {
        flex: 1;
        padding: 10px;
      }
      canvas {
        width: 100% !important;
        height: 30vh !important;
      }
      .level-table {
        max-width: 600px;
        margin: 20px auto;
        background: white;
        border-radius: 8px;
        overflow: hidden;
        box-shadow: 0 2px 4px rgba(0,0,0,0.1);
      }
      .level-table table {
        width: 100%;
        border-collapse: collapse;
      }
      .level-table th, .level-table td {
        padding: 8px 12px;
        text-align: center;
        border-bottom: 1px solid #eee;
      }
      .level-table th {
        background-color: #34495e;
        color: white;
      }
      .current-level {
        background-color: #f39c12 !important;
        color: white !important;
        font-weight: bold;
      }
      .completed-level {
        background-color: #27ae60 !important;
        color: white !important;
      }
    </style>
  </head>
  <body>
    <div class="header">
      <h1>Dryer Control System with Intelligent Fan Management</h1>
    </div>
    
    <div class="status-grid">
      <div class="status-card">
        <div class="status-title">Fan Status</div>
        <div id="fanStatus" class="fan-status">Loading...</div>
      </div>
      <div class="status-card">
        <div class="status-title">Current Dew Point</div>
        <div id="dewPoint" class="status-value">Loading...</div>
      </div>
      <div class="status-card">
        <div class="status-title">Total Drying Time</div>
        <div id="totalTime" class="status-value">Loading...</div>
      </div>
      <div class="status-card">
        <div class="status-title">Fan Cycles Completed</div>
        <div id="cyclesCompleted" class="status-value">Loading...</div>
      </div>
      <div class="status-card">
        <div class="status-title">Since Last Discharge</div>
        <div id="sinceLastTime" class="status-value">Loading...</div>
      </div>
      <div class="status-card">
        <div class="status-title">Room Starting Dew Point</div>
        <div id="initialDewPoint" class="status-value">Loading...</div>
      </div>
    </div>

    <div class="status-grid">
      <div class="status-card" style="grid-column: span 3;">
        <div class="status-title">Last Fan Trigger Details</div>
        <div id="lastTriggerInfo" class="status-value" style="font-size: 1em; line-height: 1.4;">Loading...</div>
      </div>
    </div>

    <div class="chart-container">
      <div class="chart-box"><canvas id="tempChart"></canvas></div>
      <div class="chart-box"><canvas id="humChart"></canvas></div>
      <div class="chart-box"><canvas id="dewChart"></canvas></div>
    </div>

    <div class="level-table">
      <h3>Fan Control Levels</h3>
      <table>
        <thead>
          <tr>
            <th>Level</th>
            <th>Minutes</th>
            <th>Trigger Dew Point (deg C)</th>
          </tr>
        </thead>
        <tbody id="levelTableBody">
          <tr><td>1</td><td>20</td><td>45</td></tr>
          <tr><td>2</td><td>40</td><td>42.5</td></tr>
          <tr><td>3</td><td>60</td><td>40</td></tr>
          <tr><td>4</td><td>70</td><td>37.5</td></tr>
          <tr><td>5</td><td>80</td><td>35</td></tr>
          <tr><td>6</td><td>90</td><td>32.5</td></tr>
          <tr><td>7</td><td>100</td><td>30</td></tr>
          <tr><td>8</td><td>110</td><td>29</td></tr>
          <tr><td>9</td><td>120</td><td>28</td></tr>
          <tr><td>10</td><td>130</td><td>27</td></tr>
          <tr><td>11</td><td>140</td><td>26</td></tr>
          <tr><td>12</td><td>150</td><td>25</td></tr>
        </tbody>
      </table>
    </div>

    <script>
      const tempCtx = document.getElementById('tempChart').getContext('2d');
      const humCtx = document.getElementById('humChart').getContext('2d');
      const dewCtx = document.getElementById('dewChart').getContext('2d');

      const tempData = { labels: [], datasets: [{ label: 'Temperature (deg C)', borderColor: 'red', data: [], fill: false }] };
      const humData = { labels: [], datasets: [{ label: 'Humidity (%)', borderColor: 'blue', data: [], fill: false }] };
      const dewData = { labels: [], datasets: [{ label: 'Dew Point (deg C)', borderColor: 'green', data: [], fill: false }] };

      const commonOptions = {
        responsive: true,
        plugins: {
          tooltip: {
            callbacks: {
              label: function(context) {
                return context.dataset.label + ': ' + Number(context.raw).toFixed(1);
              }
            }
          }
        },
        scales: {
          y: {
            ticks: {
              callback: function(value) {
                return Number(value).toFixed(1);
              }
            }
          }
        }
      };

      const tempChart = new Chart(tempCtx, { type: 'line', data: tempData, options: commonOptions });
      const humChart = new Chart(humCtx, { type: 'line', data: humData, options: commonOptions });
      const dewChart = new Chart(dewCtx, { type: 'line', data: dewData, options: commonOptions });

      function fetchData() {
        fetch('/data')
          .then(response => response.json())
          .then(data => {
            const now = new Date().toLocaleTimeString();

            [tempData, humData, dewData].forEach(d => d.labels.push(now));

            tempData.datasets[0].data.push(parseFloat(data.temperature));
            humData.datasets[0].data.push(parseFloat(data.humidity));
            dewData.datasets[0].data.push(parseFloat(data.dewpoint));

            // Update fan status information
            const fanStatus = document.getElementById('fanStatus');
            const fanText = data.fanRunning === 'true' ? 'RUNNING (2 min cycle)' : 
                           data.fanState === 'true' ? 'ON' : 'OFF';
            fanStatus.textContent = fanText;
            fanStatus.className = `fan-status ${data.fanState === 'true' ? 'fan-on' : 'fan-off'}`;
            
            document.getElementById('dewPoint').textContent = parseFloat(data.dewpoint).toFixed(1) + ' deg C';
            document.getElementById('totalTime').textContent = data.totalHours + 'h ' + data.totalMinutes + 'm';
            document.getElementById('cyclesCompleted').textContent = data.fanDischargeCount;
            document.getElementById('sinceLastTime').textContent = data.sinceLastDischarge + ' min';
            
            // Update initial dew point - always show the value once it's captured
            document.getElementById('initialDewPoint').textContent = parseFloat(data.initialDewPoint).toFixed(1) + ' deg C';
            
            // Update last trigger info
            const lastTriggerInfo = document.getElementById('lastTriggerInfo');
            if (data.lastTriggeredLevel > 0) {
              lastTriggerInfo.innerHTML = `
                <strong>Level ${data.lastTriggeredLevel}</strong><br>
                Temperature: ${parseFloat(data.lastTriggerTemperature).toFixed(1)} deg C<br>
                Humidity: ${parseFloat(data.lastTriggerHumidity).toFixed(1)}%<br>
                Dew Point: ${parseFloat(data.lastTriggerDewPoint).toFixed(1)} deg C
              `;
            } else {
              lastTriggerInfo.textContent = 'No Fan Discharge';
            }

            tempChart.update();
            humChart.update();
            dewChart.update();
          });
      }

      setInterval(fetchData, 2000);
    </script>
  </body>
  </html>
  )rawliteral";

  server.send(200, "text/html", html);
}

void handleData() {
  server.send(200, "application/json", getDataJson());
}

void setup() {
  Serial.begin(9600);
  Serial.println("Starting dryer control system...");
  
  Wire.begin(4, 5);  // SDA=D2 (GPIO4), SCL=D1 (GPIO5)
  
  // Initialize fan relay pin
  pinMode(FAN_RELAY_PIN, OUTPUT);
  digitalWrite(FAN_RELAY_PIN, LOW); // Start with fan OFF
  Serial.println("Fan relay initialized");
  
  // Initialize timing
  dryingStartTime = millis();
  
  delay(200);
  
  if (!bme.begin(0x76)) {
    Serial.println("Could not find a valid BME280 sensor, check wiring!");
    while (1) delay(1000);
  }

  Serial.println("BME280 sensor initialized successfully!");
  Serial.println("Dryer control system started - taking initial reading...");
  Serial.println("Fan Level Table:");
  for (int i = 0; i < NUM_LEVELS; i++) {
    Serial.print("Level ");
    Serial.print(i + 1);
    Serial.print(": ");
    Serial.print(fanLevels[i].minutes);
    Serial.print(" min -> ");
    Serial.print(fanLevels[i].dewPoint, 1);
    Serial.println(" deg C");
  }

  WiFi.begin(ssid, password);
  Serial.print("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println();
  Serial.println("WiFi connected");
  Serial.print("IP Address: ");
  Serial.println(WiFi.localIP());

  server.on("/", handleRoot);
  server.on("/data", handleData);
  server.begin();
  Serial.println("Web server started");
  Serial.println("=== System ready - entering main loop ===");
}

void loop() {
  // Read sensor data
  temperature = bme.readTemperature();
  humidity = bme.readHumidity();
  dewPoint = calculateDewPoint(temperature, humidity);

  // Control fan based on sophisticated timing and dew point logic
  controlFan();

  // Handle web requests
  server.handleClient();
  
  // Small delay to prevent overwhelming the system
  delay(1000);
}

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#include <Wire.h>

#include <SPI.h>

#include <Adafruit_Sensor.h>

#include <Adafruit_BME280.h>

#include <ESP8266WiFi.h>

#include <ESP8266WebServer.h>

const char* ssid = "Francesca";

const char* password = "DSR*5167248";

// Fan control pin (GPIO14 = D5)

const int FAN_RELAY_PIN = 14; // D5 on NodeMCU

Adafruit_BME280 bme;

ESP8266WebServer server(80);

float temperature = 0.0;

float humidity = 0.0;

float dewPoint = 0.0;

float initialDewPoint = 0.0;

bool fanState = false;

// Variables for initial dew point capture

bool initialReadingTaken = false;

// Timing variables

unsigned long dryingStartTime = 0;

unsigned long lastFanDischargeTime = 0;

unsigned long fanStartTime = 0;

bool fanRunning = false;

const unsigned long FAN_RUN_DURATION = 120000; // 2 minutes in milliseconds

// Fan level tracking

int lastTriggeredLevel = 0; // 0 means no discharge yet

int currentCycleStartLevel = 1; // For subsequent cycles

int fanDischargeCount = 0;

// Last fan trigger data

float lastTriggerTemperature = 0.0;

float lastTriggerHumidity = 0.0;

float lastTriggerDewPoint = 0.0;

// Lookup table for initial fan discharge

struct FanLevel {

int minutes;

float dewPoint;

};

const FanLevel fanLevels[] = {

{20, 45.0}, // Level 1

{40, 42.5}, // Level 2

{60, 40.0}, // Level 3

{70, 37.5}, // Level 4

{80, 35.0}, // Level 5

{90, 32.5}, // Level 6

{100, 30.0}, // Level 7

{110, 29.0}, // Level 8

{120, 28.0}, // Level 9

{130, 27.0}, // Level 10

{140, 26.0}, // Level 11

{150, 25.0} // Level 12

};

const int NUM_LEVELS = 12;

const int SUBSEQUENT_MINUTES[] = {20, 40, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150};

// Magnus formula to calculate dew point

float calculateDewPoint(float tempC, float hum) {

const float a = 17.27;

const float b = 237.7;

float alpha = ((a * tempC) / (b + tempC)) + log(hum / 100.0);

return (b * alpha) / (a - alpha);

}

// Get current elapsed time in minutes since start or last discharge

unsigned long getElapsedMinutes(bool sinceLastDischarge = false) {

unsigned long referenceTime = sinceLastDischarge ? lastFanDischargeTime : dryingStartTime;

return (millis() - referenceTime) / 60000;

}

// Control the fan based on sophisticated timing and dew point logic

void controlFan() {

// Capture initial dew point from first reading

if (!initialReadingTaken) {

initialDewPoint = dewPoint;

initialReadingTaken = true;

Serial.println("=== Initial reading captured! ===");

Serial.print("Room starting dew point: ");

Serial.print(initialDewPoint, 1);

Serial.println(" deg C");

Serial.println("Fan control system is now active.");

}

// If fan is currently running, check if 2 minutes have elapsed

if (fanRunning) {

if (millis() - fanStartTime >= FAN_RUN_DURATION) {

// Stop the fan

digitalWrite(FAN_RELAY_PIN, LOW);

fanState = false;

fanRunning = false;

lastFanDischargeTime = millis();

fanDischargeCount++;

Serial.println("Fan 2-minute cycle complete - Fan turned OFF");

Serial.print("Total fan discharges: ");

Serial.println(fanDischargeCount);

// Set up for next cycle

currentCycleStartLevel = lastTriggeredLevel;

}

return; // Don't check trigger conditions while fan is running

}

unsigned long elapsedMinutes;

bool isFirstCycle = (fanDischargeCount == 0);

if (isFirstCycle) {

// First cycle - use original table timing from drying start

elapsedMinutes = getElapsedMinutes(false);

// Check each level in the original table

for (int level = 0; level < NUM_LEVELS; level++) {

if (elapsedMinutes >= fanLevels[level].minutes && dewPoint >= fanLevels[level].dewPoint) {

// Trigger fan

digitalWrite(FAN_RELAY_PIN, HIGH);

fanState = true;

fanRunning = true;

fanStartTime = millis();

lastTriggeredLevel = level + 1; // Store as 1-based level

// Store trigger conditions

lastTriggerTemperature = temperature;

lastTriggerHumidity = humidity;

lastTriggerDewPoint = dewPoint;

Serial.print("First fan discharge triggered at Level ");

Serial.print(lastTriggeredLevel);

Serial.print(" - Elapsed: ");

Serial.print(elapsedMinutes);

Serial.print(" min, Dew Point: ");

Serial.print(dewPoint, 1);

Serial.println(" deg C - Fan ON for 2 minutes");

return;

}

} else {

// Subsequent cycles - use modified timing from last discharge

elapsedMinutes = getElapsedMinutes(true);

// Check subsequent levels starting from where we left off

for (int i = 0; i < NUM_LEVELS; i++) {

int currentLevelIndex = (currentCycleStartLevel - 1) + i; // Convert to 0-based and offset

if (currentLevelIndex >= NUM_LEVELS) break; // Don't go beyond table

if (elapsedMinutes >= SUBSEQUENT_MINUTES[i] && dewPoint >= fanLevels[currentLevelIndex].dewPoint) {

// Trigger fan

digitalWrite(FAN_RELAY_PIN, HIGH);

fanState = true;

fanRunning = true;

fanStartTime = millis();

lastTriggeredLevel = currentLevelIndex + 1; // Store as 1-based level

// Store trigger conditions

lastTriggerTemperature = temperature;

lastTriggerHumidity = humidity;

lastTriggerDewPoint = dewPoint;

Serial.print("Subsequent fan discharge triggered at Level ");

Serial.print(lastTriggeredLevel);

Serial.print(" - Elapsed since last discharge: ");

Serial.print(elapsedMinutes);

Serial.print(" min, Dew Point: ");

Serial.print(dewPoint, 1);

Serial.println(" deg C - Fan ON for 2 minutes");

return;

}

// Send formatted floats with 1 decimal place

String getDataJson() {

unsigned long totalElapsed = getElapsedMinutes(false);

unsigned long sinceLastDischarge = fanDischargeCount > 0 ? getElapsedMinutes(true) : 0;

// Convert total elapsed to hours and minutes

int totalHours = totalElapsed / 60;

int totalMinutes = totalElapsed % 60;

String json = "{";

json += "\"temperature\": " + String(temperature, 1) + ",";

json += "\"humidity\": " + String(humidity, 1) + ",";

json += "\"dewpoint\": " + String(dewPoint, 1) + ",";

json += "\"fanState\": " + String(fanState ? "true" : "false") + ",";

json += "\"fanRunning\": " + String(fanRunning ? "true" : "false") + ",";

json += "\"totalElapsed\": " + String(totalElapsed) + ",";

json += "\"totalHours\": " + String(totalHours) + ",";

json += "\"totalMinutes\": " + String(totalMinutes) + ",";

json += "\"sinceLastDischarge\": " + String(sinceLastDischarge) + ",";

json += "\"lastTriggeredLevel\": " + String(lastTriggeredLevel) + ",";

json += "\"fanDischargeCount\": " + String(fanDischargeCount) + ",";

json += "\"lastTriggerTemperature\": " + String(lastTriggerTemperature, 1) + ",";

json += "\"lastTriggerHumidity\": " + String(lastTriggerHumidity, 1) + ",";

json += "\"lastTriggerDewPoint\": " + String(lastTriggerDewPoint, 1) + ",";

json += "\"initialDewPoint\": " + String(initialDewPoint, 1) + ",";

json += "\"systemReady\": " + String(initialReadingTaken ? "true" : "false");

json += "}";

return json;

}

void handleRoot() {

String html = R"rawliteral(

<!DOCTYPE html>

<html>

<head>

<title>BME280 Dryer Control System</title>

<style>

body { font-family: Arial; text-align: center; margin: 0; padding: 0; background-color: #f5f5f5; }

.header { background-color: #2c3e50; color: white; padding: 15px; }

.status-grid {

display: grid;

grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));

gap: 15px;

padding: 20px;

max-width: 1200px;

margin: 0 auto;

}

.status-card {

background: white;

border-radius: 8px;

padding: 15px;

box-shadow: 0 2px 4px rgba(0,0,0,0.1);

}

.status-title { font-weight: bold; color: #2c3e50; margin-bottom: 5px; }

.status-value { font-size: 1.2em; color: #e74c3c; }

.fan-status { font-weight: bold; font-size: 1.3em; }

.fan-on { color: #e74c3c; }

.fan-off { color: #27ae60; }

.initializing { color: #f39c12; }

.chart-container {

display: flex;

justify-content: space-around;

align-items: center;

width: 100%;

background: white;

margin: 20px auto;

padding: 20px;

border-radius: 8px;

box-shadow: 0 2px 4px rgba(0,0,0,0.1);

max-width: 1200px;

}

.chart-box {

flex: 1;

padding: 10px;

}

canvas {

width: 100% !important;

height: 30vh !important;

}

.level-table {

max-width: 600px;

margin: 20px auto;

background: white;

border-radius: 8px;

overflow: hidden;

box-shadow: 0 2px 4px rgba(0,0,0,0.1);

}

.level-table table {

width: 100%;

border-collapse: collapse;

}

.level-table th, .level-table td {

padding: 8px 12px;

text-align: center;

border-bottom: 1px solid #eee;

}

.level-table th {

background-color: #34495e;

color: white;

}

.current-level {

background-color: #f39c12 !important;

color: white !important;

font-weight: bold;

}

.completed-level {

background-color: #27ae60 !important;

color: white !important;

}

</style>

</head>

<body>

<h1>Dryer Control System with Intelligent Fan Management</h1>

</div>

<div class="status-title">Fan Status</div>

<div id="fanStatus" class="fan-status">Loading...</div>

</div>

<div class="status-title">Current Dew Point</div>

<div id="dewPoint" class="status-value">Loading...</div>

</div>

<div class="status-title">Total Drying Time</div>

<div id="totalTime" class="status-value">Loading...</div>

</div>

<div class="status-title">Fan Cycles Completed</div>

<div id="cyclesCompleted" class="status-value">Loading...</div>

</div>

<div class="status-title">Since Last Discharge</div>

<div id="sinceLastTime" class="status-value">Loading...</div>

</div>

<div class="status-title">Room Starting Dew Point</div>

<div id="initialDewPoint" class="status-value">Loading...</div>

</div>

<div class="status-title">Last Fan Trigger Details</div>

<div id="lastTriggerInfo" class="status-value" style="font-size: 1em; line-height: 1.4;">Loading...</div>

</div>

</div>

<h3>Fan Control Levels</h3>

<table>

<thead>

<tr>

<th>Level</th>

<th>Minutes</th>

<th>Trigger Dew Point (deg C)</th>

</tr>

</thead>

</tbody>

</table>

</div>

const tempCtx = document.getElementById('tempChart').getContext('2d');

const humCtx = document.getElementById('humChart').getContext('2d');

const dewCtx = document.getElementById('dewChart').getContext('2d');

const tempData = { labels: [], datasets: [{ label: 'Temperature (deg C)', borderColor: 'red', data: [], fill: false }] };

const humData = { labels: [], datasets: [{ label: 'Humidity (%)', borderColor: 'blue', data: [], fill: false }] };

const dewData = { labels: [], datasets: [{ label: 'Dew Point (deg C)', borderColor: 'green', data: [], fill: false }] };

const commonOptions = {

responsive: true,

plugins: {

tooltip: {

callbacks: {

label: function(context) {

return context.dataset.label + ': ' + Number(context.raw).toFixed(1);

}

scales: {

y: {

ticks: {

callback: function(value) {

return Number(value).toFixed(1);

}

};

const tempChart = new Chart(tempCtx, { type: 'line', data: tempData, options: commonOptions });

const humChart = new Chart(humCtx, { type: 'line', data: humData, options: commonOptions });

const dewChart = new Chart(dewCtx, { type: 'line', data: dewData, options: commonOptions });

function fetchData() {

fetch('/data')

.then(response => response.json())

.then(data => {

const now = new Date().toLocaleTimeString();

[tempData, humData, dewData].forEach(d => d.labels.push(now));

tempData.datasets[0].data.push(parseFloat(data.temperature));

humData.datasets[0].data.push(parseFloat(data.humidity));

dewData.datasets[0].data.push(parseFloat(data.dewpoint));

// Update fan status information

const fanStatus = document.getElementById('fanStatus');

const fanText = data.fanRunning === 'true' ? 'RUNNING (2 min cycle)' :

data.fanState === 'true' ? 'ON' : 'OFF';

fanStatus.textContent = fanText;

fanStatus.className = `fan-status ${data.fanState === 'true' ? 'fan-on' : 'fan-off'}`;

document.getElementById('dewPoint').textContent = parseFloat(data.dewpoint).toFixed(1) + ' deg C';

document.getElementById('totalTime').textContent = data.totalHours + 'h ' + data.totalMinutes + 'm';

document.getElementById('cyclesCompleted').textContent = data.fanDischargeCount;

document.getElementById('sinceLastTime').textContent = data.sinceLastDischarge + ' min';

// Update initial dew point - always show the value once it's captured

document.getElementById('initialDewPoint').textContent = parseFloat(data.initialDewPoint).toFixed(1) + ' deg C';

// Update last trigger info

const lastTriggerInfo = document.getElementById('lastTriggerInfo');

if (data.lastTriggeredLevel > 0) {

lastTriggerInfo.innerHTML = `

<strong>Level ${data.lastTriggeredLevel}</strong><br>

Temperature: ${parseFloat(data.lastTriggerTemperature).toFixed(1)} deg C<br>

Humidity: ${parseFloat(data.lastTriggerHumidity).toFixed(1)}%<br>

Dew Point: ${parseFloat(data.lastTriggerDewPoint).toFixed(1)} deg C

} else {

lastTriggerInfo.textContent = 'No Fan Discharge';

}

tempChart.update();

humChart.update();

dewChart.update();

});

}

setInterval(fetchData, 2000);

</script>

</body>

</html>

)rawliteral";

server.send(200, "text/html", html);

}

void handleData() {

server.send(200, "application/json", getDataJson());

}

void setup() {

Serial.begin(9600);

Serial.println("Starting dryer control system...");

Wire.begin(4, 5); // SDA=D2 (GPIO4), SCL=D1 (GPIO5)

// Initialize fan relay pin

pinMode(FAN_RELAY_PIN, OUTPUT);

digitalWrite(FAN_RELAY_PIN, LOW); // Start with fan OFF

Serial.println("Fan relay initialized");

// Initialize timing

dryingStartTime = millis();

delay(200);

if (!bme.begin(0x76)) {

Serial.println("Could not find a valid BME280 sensor, check wiring!");

while (1) delay(1000);

}

Serial.println("BME280 sensor initialized successfully!");

Serial.println("Dryer control system started - taking initial reading...");

Serial.println("Fan Level Table:");

for (int i = 0; i < NUM_LEVELS; i++) {

Serial.print("Level ");

Serial.print(i + 1);

Serial.print(": ");

Serial.print(fanLevels[i].minutes);

Serial.print(" min -> ");

Serial.print(fanLevels[i].dewPoint, 1);

Serial.println(" deg C");

}

WiFi.begin(ssid, password);

Serial.print("Connecting to WiFi");

while (WiFi.status() != WL_CONNECTED) {

delay(500);

Serial.print(".");

}

Serial.println();

Serial.println("WiFi connected");

Serial.print("IP Address: ");

Serial.println(WiFi.localIP());

server.on("/", handleRoot);

server.on("/data", handleData);

server.begin();

Serial.println("Web server started");

Serial.println("=== System ready - entering main loop ===");

}

void loop() {

// Read sensor data

temperature = bme.readTemperature();

humidity = bme.readHumidity();

dewPoint = calculateDewPoint(temperature, humidity);

// Control fan based on sophisticated timing and dew point logic

controlFan();

// Handle web requests

server.handleClient();

// Small delay to prevent overwhelming the system

delay(1000);

}