macrocell_office_iot/espsens/espsens.ino

177 lines
5.5 KiB
C++

/* 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 <ESP8266WiFi.h>
#include <Wire.h>
#include <PubSubClient.h>
#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_ABHU TOPIC_BASE "abs_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 1.5 // humidity doesn't change that much anyways
#define DIFF_ABHU 0.2 // small changes mean quite something
#define DIFF_HEAT 0.3 // this one's actually quite active
struct Sensor {
String desc; // sensor description
char* topic; // sensor topic
float diff; // value difference for an update
float value; // current values
float lastValue; // value at last update
int lastUpdate; // number of samples since last update
};
Sensor temp = {"temperature (°C)", TOPIC_TEMP, DIFF_TEMP, 0.0, 0.0, -1}; // temperature
Sensor hmid = {"humidity (%)", TOPIC_HMID, DIFF_HMID, 0.0, 0.0, -1}; // humidity
Sensor abhu = {"absolute humidity (gr/m³)", TOPIC_ABHU, DIFF_ABHU, 0.0, 0.0, -1}; // absolute humidity
Sensor heat = {"heat index (°C)", TOPIC_HEAT, DIFF_HEAT, 0.0, 0.0, -1}; // 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;
void publish (Sensor &sensor){
bool force = false;
Serial.println("Sample " + sensor.desc + ": " + String(sensor.value).c_str());
// check if first sample, set lastValue and return
if (sensor.lastUpdate == -1){
sensor.lastValue = sensor.value;
return;
}
// force an update if the number of samples without update is exceeded
Serial.println(" * Forcing publication if sensor value is plausible");
force = sensor.lastUpdate >= FORCE_PERIOD;
// update the sample counter, will be reset if sample is published
sensor.lastUpdate += 1;
// check if there was sufficient variation on the signal and if the value is plausible
if (checkVariation(sensor.value, sensor.lastValue, sensor.diff) or force) {
Serial.println(" Sufficient variation on " + sensor.desc + ": " + String(sensor.value).c_str());
if (checkPlausibility(sensor.value, sensor.lastValue, sensor.diff)) {
Serial.println(" Value published");
client.publish(sensor.topic, String(sensor.value).c_str(), true);
sensor.lastUpdate = 0;
} else {
Serial.print(" ** ERROR: Value out of bounds, not published. Last value :");
Serial.println(String(sensor.lastValue).c_str());
}
sensor.lastValue = sensor.value;
}
}
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.value = dht.readHumidity();
temp.value = dht.readTemperature();
if (!isnan(hmid.value) && !isnan(temp.value)){
abhu.value = (6.112 * ( pow(2.71828, ((17.67 * temp.value) / (temp.value + 243.5))) * hmid.value * 2.1674)) / (273.15 + temp.value);
heat.value = dht.computeHeatIndex(temp.value, hmid.value, false);
}
publish(temp);
publish(hmid);
publish(heat);
publish(abhu);
}
}