/* 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 DIFF_TEMP 0.3 // sensor has only 0.5°C accuracy, triggering on less is ludicrous #define DIFF_HMID 2.5 // humidity doesn't change that much anyways #define DIFF_HEAT 0.2 // this one's actually quite active #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 checkBound(float newValue, float prevValue, float maxDiff) { return !isnan(newValue) && (newValue < prevValue - maxDiff || newValue > prevValue + maxDiff); } long lastMsg = 0; float t_r = 0.0; float h_r = 0.0; float hi_r = 0.0; long lastSent = 0; bool published = false; bool forcePublish = false; bool publish (String desc, char *topic, float val, float &val_r, int diff, bool force){ if (checkBound(val, val_r, 0.3) or force) { val_r = val; Serial.print("New " + desc + ": "); Serial.println(String(val).c_str()); client.publish(topic, String(val).c_str(), true); return true; } else { return false; } } 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);} float h = dht.readHumidity(); float t = dht.readTemperature(); if (isnan(h) || isnan(t)) { Serial.println(F("Failed to read from DHT sensor!")); return; } float hi = dht.computeHeatIndex(t, h, false); Serial.print(F("Humidity: ")); Serial.print(h); Serial.print(F("% Temperature: ")); Serial.print(t); Serial.print(F("°C Heat index: ")); Serial.print(hi); Serial.println(F("°C ")); published = false; if (lastSent > FORCE_PERIOD) { Serial.println(F("Forcing a publish of all values")); forcePublish = true; lastSent = 0; } published += publish("temperature", TOPIC_TEMP, t, t_r, DIFF_TEMP, forcePublish); published += publish("humidity", TOPIC_HMID, h, h_r, DIFF_HMID, forcePublish); published += publish("heat index", TOPIC_HEAT, hi, hi_r, DIFF_HEAT, forcePublish); if (published == false) { lastSent = lastSent + 1; } else { lastSent = 0; } forcePublish = false; } }