/* HocLapTrinhRobot G2 08 - Canh bao moi truong bang LED va buzzer Board: ESP32-S3 DevKit Hardware: SHT31 I2C, LDR voltage divider, MQ-135 analog, LED, active buzzer */ #include enum OverallState { STATE_NORMAL, STATE_WATCH, STATE_ALERT }; const int PIN_I2C_SDA = 8; const int PIN_I2C_SCL = 9; const int PIN_LDR = 4; const int PIN_MQ135 = 6; const int PIN_LED = 2; const int PIN_BUZZER = 15; const uint8_t SHT31_ADDR = 0x44; const unsigned long SAMPLE_INTERVAL_MS = 1000; const unsigned long MQ_WARMUP_MS = 60000; const unsigned long ACK_MUTE_MS = 15000; const float EMA_ALPHA = 0.18f; const float TEMP_WATCH = 32.0f; const float TEMP_ALERT_ON = 34.0f; const float TEMP_ALERT_OFF = 33.0f; const float HUM_WATCH = 78.0f; const float HUM_ALERT_ON = 85.0f; const float HUM_ALERT_OFF = 80.0f; const float LIGHT_WATCH = 25.0f; const float LIGHT_ALERT_ON = 15.0f; const float LIGHT_ALERT_OFF = 20.0f; const float AIR_WATCH = 45.0f; const float AIR_ALERT_ON = 60.0f; const float AIR_ALERT_OFF = 50.0f; int gasBaselineRaw = 1800; bool filtersReady = false; unsigned long lastSampleMs = 0; unsigned long mutedUntilMs = 0; float tempFiltered = 0.0f; float humFiltered = 0.0f; float lightFiltered = 0.0f; float airFiltered = 0.0f; bool tempAlert = false; bool humAlert = false; bool lightAlert = false; bool airAlert = false; OverallState currentState = STATE_NORMAL; uint8_t crc8(const uint8_t *data, int len) { uint8_t crc = 0xFF; for (int i = 0; i < len; i++) { crc ^= data[i]; for (int bit = 0; bit < 8; bit++) { crc = (crc & 0x80) ? (crc << 1) ^ 0x31 : (crc << 1); } } return crc; } bool readSht31(float &temperatureC, float &humidityPercent) { Wire.beginTransmission(SHT31_ADDR); Wire.write(0x24); Wire.write(0x00); if (Wire.endTransmission() != 0) return false; delay(20); if (Wire.requestFrom((int)SHT31_ADDR, 6) != 6) return false; uint8_t data[6]; for (int i = 0; i < 6; i++) data[i] = Wire.read(); if (crc8(data, 2) != data[2] || crc8(data + 3, 2) != data[5]) return false; uint16_t rawTemp = ((uint16_t)data[0] << 8) | data[1]; uint16_t rawHum = ((uint16_t)data[3] << 8) | data[4]; temperatureC = -45.0f + 175.0f * ((float)rawTemp / 65535.0f); humidityPercent = 100.0f * ((float)rawHum / 65535.0f); return true; } int readAnalogAverage(int pin, int sampleCount) { long total = 0; for (int i = 0; i < sampleCount; i++) { total += analogRead(pin); delay(2); } return total / sampleCount; } float constrainFloat(float value, float low, float high) { if (value < low) return low; if (value > high) return high; return value; } float lightPercentFromRaw(int raw) { return constrainFloat((raw / 4095.0f) * 100.0f, 0.0f, 100.0f); } float airScoreFromRaw(int raw) { return constrainFloat((raw - gasBaselineRaw) / 12.0f, 0.0f, 100.0f); } float updateEma(float previous, float sample, bool initialized) { if (!initialized) return sample; return previous + EMA_ALPHA * (sample - previous); } bool updateHighLatch(bool active, float value, float onLevel, float offLevel) { if (!active && value > onLevel) return true; if (active && value < offLevel) return false; return active; } bool updateLowLatch(bool active, float value, float onLevel, float offLevel) { if (!active && value < onLevel) return true; if (active && value > offLevel) return false; return active; } void updateAlertLatches() { bool gasReady = millis() >= MQ_WARMUP_MS; tempAlert = updateHighLatch(tempAlert, tempFiltered, TEMP_ALERT_ON, TEMP_ALERT_OFF); humAlert = updateHighLatch(humAlert, humFiltered, HUM_ALERT_ON, HUM_ALERT_OFF); lightAlert = updateLowLatch(lightAlert, lightFiltered, LIGHT_ALERT_ON, LIGHT_ALERT_OFF); if (gasReady) { airAlert = updateHighLatch(airAlert, airFiltered, AIR_ALERT_ON, AIR_ALERT_OFF); } else { airAlert = false; } } OverallState chooseOverallState() { if (tempAlert || humAlert || lightAlert || airAlert) { return STATE_ALERT; } bool gasReady = millis() >= MQ_WARMUP_MS; bool watch = tempFiltered > TEMP_WATCH || humFiltered > HUM_WATCH || lightFiltered < LIGHT_WATCH || (gasReady && airFiltered > AIR_WATCH); return watch ? STATE_WATCH : STATE_NORMAL; } const char *stateName(OverallState state) { if (state == STATE_ALERT) return "ALERT"; if (state == STATE_WATCH) return "WATCH"; return "NORMAL"; } String buildCauseText() { String causes = ""; if (tempAlert) causes += "TEMP|"; if (humAlert) causes += "HUM|"; if (lightAlert) causes += "LIGHT|"; if (airAlert) causes += "AIR|"; if (causes.length() == 0) { if (currentState == STATE_WATCH) return "WATCH_LIMIT"; return "NONE"; } causes.remove(causes.length() - 1); return causes; } void updateLed() { if (currentState == STATE_ALERT) { digitalWrite(PIN_LED, HIGH); } else if (currentState == STATE_WATCH) { digitalWrite(PIN_LED, ((millis() / 600) % 2 == 0) ? HIGH : LOW); } else { digitalWrite(PIN_LED, LOW); } } void updateBuzzer() { bool muted = millis() < mutedUntilMs; bool beepOn = currentState == STATE_ALERT && !muted && (millis() % 900 < 120); digitalWrite(PIN_BUZZER, beepOn ? HIGH : LOW); } void calibrateGasBaseline() { gasBaselineRaw = readAnalogAverage(PIN_MQ135, 40); airAlert = false; Serial.print("baseline_gas_raw="); Serial.println(gasBaselineRaw); } void handleSerialCommand() { if (!Serial.available()) return; String command = Serial.readStringUntil('\n'); command.trim(); command.toUpperCase(); if (command == "BASELINE GAS") { calibrateGasBaseline(); } else if (command == "RESET FILTER") { filtersReady = false; tempAlert = false; humAlert = false; lightAlert = false; airAlert = false; Serial.println("filters_reset=OK"); } else if (command == "ACK") { mutedUntilMs = millis() + ACK_MUTE_MS; Serial.println("ack=OK buzzer_muted_ms=15000"); } else if (command == "STATUS") { Serial.print("status baseline="); Serial.print(gasBaselineRaw); Serial.print(" state="); Serial.print(stateName(currentState)); Serial.print(" muted="); Serial.println(millis() < mutedUntilMs ? "YES" : "NO"); } else if (command.length() > 0) { Serial.println("commands: BASELINE GAS | RESET FILTER | ACK | STATUS"); } } void setup() { Serial.begin(115200); delay(400); pinMode(PIN_LED, OUTPUT); pinMode(PIN_BUZZER, OUTPUT); digitalWrite(PIN_LED, LOW); digitalWrite(PIN_BUZZER, LOW); analogReadResolution(12); Wire.begin(PIN_I2C_SDA, PIN_I2C_SCL); Serial.println("G2 08 LED buzzer alert ready"); Serial.println("commands: BASELINE GAS | RESET FILTER | ACK | STATUS"); } void loop() { handleSerialCommand(); updateLed(); updateBuzzer(); unsigned long now = millis(); if (now - lastSampleMs < SAMPLE_INTERVAL_MS) { return; } lastSampleMs = now; float tempRaw = tempFiltered; float humRaw = humFiltered; bool shtOk = readSht31(tempRaw, humRaw); if (!shtOk && !filtersReady) { tempRaw = 0.0f; humRaw = 0.0f; } int ldrRaw = readAnalogAverage(PIN_LDR, 12); int mqRaw = readAnalogAverage(PIN_MQ135, 12); float lightRaw = lightPercentFromRaw(ldrRaw); float airRaw = airScoreFromRaw(mqRaw); tempFiltered = updateEma(tempFiltered, tempRaw, filtersReady); humFiltered = updateEma(humFiltered, humRaw, filtersReady); lightFiltered = updateEma(lightFiltered, lightRaw, filtersReady); airFiltered = updateEma(airFiltered, airRaw, filtersReady); filtersReady = true; updateAlertLatches(); currentState = chooseOverallState(); updateLed(); updateBuzzer(); Serial.print("t_ms="); Serial.print(now); Serial.print(" sht="); Serial.print(shtOk ? "OK" : "ERR"); Serial.print(" state="); Serial.print(stateName(currentState)); Serial.print(" causes="); Serial.print(buildCauseText()); Serial.print(" temp="); Serial.print(tempFiltered, 1); Serial.print(" hum="); Serial.print(humFiltered, 1); Serial.print(" light="); Serial.print(lightFiltered, 1); Serial.print(" air="); Serial.print(airFiltered, 1); Serial.print(" muted="); Serial.println(millis() < mutedUntilMs ? "YES" : "NO"); }

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