#include #include #include #define SERVO_PIN 11 #define SENSORHT 7 #define HEAT_RESISTOR 12 int LDR_PIN = A0; SimpleDHT22 sensorht; LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27, 16 column and 2 rows Servo myservo; // create servo object to control a servo // LDR Characteristics const float GAMMA = 0.7; const float RL10 = 50; // Function prototypes void printLCD(String name, int number = -1, int delayMS = 0, String text = "none"); void updateSensorData(); int getLux(); String getAirQuality(); String getWindDirection(); // Variables to avoid blocking the system unsigned long previousMillisDisplay = 0; unsigned long previousMillisTemperature = 0; unsigned long previousMillisLEDs = 0; const long displayInterval = 2000; // Screen change interval (in milliseconds) const long deltaTemperatureInterval = 500; //This is how fast the temperature will be changing when applying hot/cold to the batteries const long deltaLedIndicatorInterval = 1000; //This is how fast the LED indicator for temperature will be updated int currentDisplay = 0; byte lastTemperature = 0; byte lastHumidity = 0; int lastLux = 0; String lastAirQuality = ""; String lastWindDirection = ""; int lastPos = 0; // variable to store the servo position int currentBatteryTemp = 10; String batteryAction = "NONE"; //The action to the batteries can be HEAT, NONE, COOL int servoPos = 0; // The 74HC595 uses a type of serial connection called SPI (Serial Peripheral Interface) that requires three pins: int datapin = 2; int clockpin = 3; int latchpin = 4; // We'll also declare a global variable for the data we're // sending to the shift register: byte data = 0; /* Hysteresis diagram --> Level 0: Heat battery, Level 1: Do nothing, Level 2: Heat Battery * * * level * ^ * | * 4_| * | * | * | * 3_| * | * | * | * 2_|. . . . . . . . __________ * | | | * | v ^ * | | | * 1_|. . .___________|__| * | | | . . * | v ^ . . * | | | . . * 0_|_____|__|______________________________________| temperature in centigrades * | | | | * 5 10 45 50 * */ struct threshold { unsigned int low; unsigned int high; unsigned int level; }; // number os thresholds const int NB_THRESHOLDS = 2; // definition of the thresholds const struct threshold thresholds[NB_THRESHOLDS] = { {5, 10, 1}, // low, high, level {45, 50, 2} }; // Hysteresis function (inspiration from https://github.com/lille-boy/hysteresis/blob/master/hysteresis.c) unsigned int hysteresis(unsigned int input_temp) { static unsigned int current_level = 0; static unsigned int prev_temp = 0; if (input_temp >= prev_temp) { // Ascending - use high threshold for (int i = 0; i < NB_THRESHOLDS; i++) { if (input_temp >= thresholds[i].high && thresholds[i].level > current_level) { current_level = thresholds[i].level; } } } else { // Descending - use low threshold for (int i = NB_THRESHOLDS - 1; i >= 0; i--) { if (current_level == thresholds[i].level && input_temp <= thresholds[i].low) { current_level = thresholds[i].level - 1; break; } } } prev_temp = input_temp; return current_level; } void clearSerialMonitor() { for (int i = 0; i < 50; i++) { Serial.println(); } } void shiftWrite(int desiredPin, boolean desiredState){ // This function lets you make the shift register outputs // HIGH or LOW in exactly the same way that you use digitalWrite(). bitWrite(data,desiredPin,desiredState); //Change desired bit to 0 or 1 in "data" // Now we'll actually send that data to the shift register. // The shiftOut() function does all the hard work of // manipulating the data and clock pins to move the data // into the shift register: shiftOut(datapin, clockpin, MSBFIRST, data); //Send "data" to the shift register //Toggle the latchPin to make "data" appear at the outputs digitalWrite(latchpin, HIGH); digitalWrite(latchpin, LOW); } /* _____ ______ _______ _ _ _____ / ____| ____|__ __| | | | __ \ | (___ | |__ | | | | | | |__) | \___ \| __| | | | | | | ___/ ____) | |____ | | | |__| | | |_____/|______| |_| \____/|_| */ void setup() { //------- DHT22 setup ------- pinMode(SENSORHT, INPUT); Serial.println("DHT22 started!"); //------- LCD setup ---------- lcd.init(); // initialize the lcd lcd.backlight(); //------- LDR setup ------- pinMode(LDR_PIN, INPUT); //------- Servo for cooling ----- myservo.attach(SERVO_PIN); // attaches the servo on pin 9 to the servo object //built-in led pinMode(LED_BUILTIN, OUTPUT); //heat resistor led pinMode(HEAT_RESISTOR, OUTPUT); // initialize 74HC595 pins pinMode(datapin, OUTPUT); pinMode(clockpin, OUTPUT); pinMode(latchpin, OUTPUT); Serial.begin(9600); } /* _ ____ ____ _____ | | / __ \ / __ \| __ \ | | | | | | | | | |__) | | | | | | | | | | ___/ | |___| |__| | |__| | | |______\____/ \____/|_| */ void loop() { unsigned long currentMillis = millis(); // Update sensors continuously updateSensorData(); // Update the display in a non-blocking way if (currentMillis - previousMillisDisplay >= displayInterval || batteryAction != "NONE") { previousMillisDisplay = currentMillis; if(batteryAction == "NONE"){ switch(currentDisplay) { case 0: printLCD("Temperature (*C):", (int)lastTemperature); break; case 1: printLCD("Humidity (%):", (int)lastHumidity); break; case 2: printLCD("Luxes:", lastLux); break; case 3: printLCD("Air quality: ", -1, 0, lastAirQuality); break; case 4: printLCD("Wind Direction: ", -1, 0, lastWindDirection); break; } }else{ printLCD("Battery Action!: ", -1, 0, batteryAction); } currentDisplay = (currentDisplay + 1) % 5; // Show the next param in the screen } if (currentMillis - previousMillisLEDs >= deltaLedIndicatorInterval) { previousMillisLEDs = currentMillis; updateLedIndicator(); } // This part of the code is the one in charge of managing the actions of the hysteresis if(currentMillis - previousMillisTemperature >= deltaTemperatureInterval){ previousMillisTemperature = currentMillis; if(currentBatteryTemp != (int)lastTemperature && abs(currentBatteryTemp - (int)lastTemperature) > 0.5){ unsigned int currentLevel = hysteresis((int)currentBatteryTemp); if(currentLevel == 1){ // the battery does not need action batteryAction = "NONE"; myservo.write(-90); digitalWrite(HEAT_RESISTOR, LOW); if(currentBatteryTemp - (int)lastTemperature < 0){ currentBatteryTemp += 1; }else{ currentBatteryTemp -= 1; } } if(currentLevel == 2){ // the battery needs cooling batteryAction = "COOL"; myservo.write(90); currentBatteryTemp -= 1; } if(currentLevel == 0){ // the battery needs heat batteryAction = "HEAT"; digitalWrite(HEAT_RESISTOR, HIGH); currentBatteryTemp += 1; } // emulating a clear log to read better clearSerialMonitor(); Serial.println("----------------------------------------------------------"); Serial.println("Ambient Temperature: " + String((int)lastTemperature)); Serial.println("Battery Current Temperature: " + String(currentBatteryTemp)); Serial.println("Current Action: " + batteryAction); Serial.println("----------------------------------------------------------"); } } //day/night indicator (led ON when night) (lastLux > 50) ? digitalWrite(LED_BUILTIN, LOW) : digitalWrite(LED_BUILTIN, HIGH); } void updateSensorData() { //------- DHT22 data reading ---------- byte temperature = 0; byte humidity = 0; byte data[40] = {0}; if(!sensorht.read(SENSORHT, &temperature, &humidity, data)) { lastTemperature = temperature; lastHumidity = humidity; } // Update other sensors lastLux = getLux(); lastAirQuality = getAirQuality(); lastWindDirection = getWindDirection(); } // printLCD without delay void printLCD(String name, int number = -1, int delayMS = 0, String text = "none"){ lcd.clear(); lcd.setCursor(0, 0); lcd.print(name); lcd.setCursor(2, 1); if(number != -1) lcd.print(number); else lcd.print(text); } int getLux(){ int analogValue = analogRead(A0); float voltage = analogValue / 1024. * 5; float resistance = 2000 * voltage / (1 - voltage / 5); float lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA)); return lux; } String getAirQuality(){ int analogValue = analogRead(A1); if(analogValue > 515) return "Good!"; else return "Bad :("; } String getWindDirection(){ int y = analogRead(A2); int x = analogRead(A3); const int DEADZONE = 100; int centerX = 512; int centerY = 512; if (abs(x - centerX) < DEADZONE && abs(y - centerY) < DEADZONE) { return "no wind"; } if (abs(x - centerX) > abs(y - centerY)) { if (x > centerX + DEADZONE) return "West"; if (x < centerX - DEADZONE) return "East"; } else { if (y > centerY + DEADZONE) return "North"; if (y < centerY - DEADZONE) return "South"; } return "wind error"; } void updateLedIndicator(){ // constrain the value before mapping int constrainedLux = constrain(lastLux, 0, 10000); // map to 0-8 because we have 8 leds int ledsToTurnOn = map(constrainedLux, 0, 10000, 0, 9); // avois getting out of range ledsToTurnOn = constrain(ledsToTurnOn, 0, 8); // Turn on the necessary LEDs for (int i = 0; i < ledsToTurnOn; i++) { shiftWrite(i, HIGH); } // Turn off the rest for (int i = ledsToTurnOn; i < 8; i++) { shiftWrite(i, LOW); } }