/* ESP8266 environmental sensor project * * This firmware provides features to use the NodeMCU ESP12 unit as an environmental sensor. * Currently supported is the DHT22 temperature and humidity sensor. * The sensor is to be connected to pin D2 of the NodeMCU ESP12 breakout card pin. * * (C) 2019 Macrocell - Environmental sensing solutions * proudly presented by Macrocell - FPGA Innovators */ #include #include #include #include "DHT.h" #include "configuration.h" #define TOPIC_BASE "sensor/" SENSOR_ID "/" #define TOPIC_TEMP TOPIC_BASE "temperature" #define TOPIC_HMID TOPIC_BASE "humidity" #define TOPIC_HEAT TOPIC_BASE "heat_index" #define TOPIC_ABHU TOPIC_BASE "abs_humidity" #define DIFF_TEMP 0.3 // sensor has only 0.5°C accuracy, triggering on less is ludicrous #define DIFF_HMID 1.5 // humidity doesn't change that much anyways #define DIFF_HEAT 0.3 // this one's actually quite active #define DIFF_ABHU 0.2 // small changes mean quite something float hmid = 0; // humidity float hmid_r = 0; // humidity float abhu = 0; // absolute humidity float abhu_r = 0; // absolute humidity float temp = 0; // temperature float temp_r = 0; // temperature float heat = 0; // heat index float heat_r = 0; // heat index #define DHTPIN 4 // Digital pin connected to the DHT sensor #define DHTTYPE DHT22 // DHT 22 (AM2302), AM2321 DHT dht(DHTPIN, DHTTYPE); WiFiClient espClient; PubSubClient client(espClient); void setup() { Serial.begin(SERIAL_BAUDRATE); pinMode(LED_BUILTIN, OUTPUT); digitalWrite(LED_BUILTIN, LOW); setup_wifi(); client.setServer(MQTT_SERVER, MQTT_PORT); dht.begin(); } void setup_wifi() { delay(10); // Connect to a WiFi network Serial.println(); Serial.print("Connecting to "); Serial.println(WIFI_SSID); WiFi.begin(WIFI_SSID, WIFI_PW); WiFi.mode(WIFI_STA); // blink LED fast until WiFi is connected while (WiFi.status() != WL_CONNECTED) { delay(200); digitalWrite(LED_BUILTIN, HIGH); Serial.print("."); delay(200); digitalWrite(LED_BUILTIN, LOW); } // WiFi connected Serial.println(""); Serial.println("WiFi connected"); Serial.println("IP address: "); Serial.println(WiFi.localIP()); } void reconnect() { // Loop until reconnected while (!client.connected()) { Serial.print("Attempting MQTT connection..."); // Attempt to connect if (client.connect(MQTT_CLIENT, MQTT_USER, MQTT_PW)) { Serial.println("connected"); } else { Serial.print("failed, rc="); Serial.print(client.state()); Serial.println(" try again in 5 seconds"); digitalWrite(LED_BUILTIN, HIGH); // Wait 5 seconds before retrying delay(4000); digitalWrite(LED_BUILTIN, LOW); delay(1000); } } } bool checkVariation(float newValue, float prevValue, float maxDiff) { return !isnan(newValue) && (newValue < prevValue - maxDiff || newValue > prevValue + maxDiff); } bool checkPlausibility(float newValue, float prevValue, float maxDiff) { return (newValue < prevValue + (maxDiff * 10) || newValue > prevValue - (maxDiff * 10)); } long lastMsg = 0; long lastSent = 0; bool published = false; bool forcePublish = false; bool publish (String desc, char *topic, float val, float &lastVal, float diff, bool force){ bool ret = false; Serial.println("Sample " + desc + ": " + String(val).c_str()); if (checkVariation(val, lastVal, diff) or force) { Serial.println("Sufficient variation on " + desc + ": " + String(val).c_str()); if (checkPlausibility(val, lastVal, diff) or force) { Serial.println("Value published"); client.publish(topic, String(val).c_str(), true); ret = true; } else { Serial.print("** ERROR: Value out of bounds, not published. Last value :"); Serial.println(String(lastVal).c_str()); } lastVal = val; } return ret; } void loop() { if (!client.connected()) { reconnect(); } client.loop(); digitalWrite(LED_BUILTIN, HIGH); long now = millis(); if (now - lastMsg > OPERATION_PERIOD / 2) { if (OPERATION_BLINK_EN) {digitalWrite(LED_BUILTIN, LOW);} } if (now - lastMsg > OPERATION_PERIOD) { lastMsg = now; if (OPERATION_BLINK_EN) {digitalWrite(LED_BUILTIN, HIGH);} hmid = dht.readHumidity(); temp = dht.readTemperature(); if (!isnan(hmid) && !isnan(temp)){ abhu = (6.112 * ( pow(2.71828, ((17.67 * temp) / (temp + 243.5))) * hmid * 2.1674)) / (273.15 + temp); heat = dht.computeHeatIndex(temp, hmid, false); } published = false; if (lastSent > FORCE_PERIOD) { Serial.println(F("Forcing a publish of all values")); forcePublish = true; lastSent = 0; } published += publish("temperature", TOPIC_TEMP, temp, temp_r, DIFF_TEMP, forcePublish); published += publish("humidity", TOPIC_HMID, hmid, hmid_r, DIFF_HMID, forcePublish); published += publish("heat index", TOPIC_HEAT, heat, heat_r, DIFF_HEAT, forcePublish); published += publish("absolute humidity", TOPIC_ABHU, abhu, abhu_r, DIFF_ABHU, forcePublish); if (published == false) { lastSent = lastSent + 1; } else { lastSent = 0; } forcePublish = false; } }