Perform the MQTT connection during the setup

include/config.h

@@ -20,6 +20,6 @@ void initialize_config(Config *config, JsonDocument json);
 
 bool load_config_file(const char *file_path, Config *config);
 
-long minutes_to_microseconds(int minutes);
+long minutes_to_milliseconds(int minutes);
 
 #endif // CONFIG_H_

include/sensor.h

@@ -0,0 +1,14 @@
+#ifndef SENSOR_H_
+#define SENSOR_H_
+
+#include <SensirionI2cScd4x.h>
+
+void handle_error(int code, char *msg);
+
+void initialize_sensor(SensirionI2cScd4x &sensor, int error_code,
+                       char *error_msg);
+
+void read_values(SensirionI2cScd4x &sensor, float *data, int error_code,
+                 char *error_msg);
+
+#endif // SENSOR_H_

src/config.cpp

@@ -10,7 +10,7 @@ void initialize_config(Config *config, JsonDocument json) {
     config->topic = strdup(json["mqtt_topic"]);
     config->device_id = strdup(json["device_id"]);
     config->mqtt_port = json["mqtt_port"];
-    config->sleep_time = minutes_to_microseconds(json["sleep_time"]);
+    config->sleep_time = minutes_to_milliseconds(json["sleep_time"]);
     config->connection_attempts = json["connection_attempts"];
 }
 
@@ -28,4 +28,4 @@ bool load_config_file(const char *file_path, Config *config) {
     return true;
 }
 
-long minutes_to_microseconds(int minutes) { return (minutes * 6e7); }
+long minutes_to_milliseconds(int minutes) { return (minutes * 6e4); }

src/main.cpp

@@ -1,63 +1,36 @@
+#include "config.h"
+#include "sensor.h"
 #include "wlan.h"
 #include <Arduino.h>
 #include <ESP8266WiFi.h>
 #include <PubSubClient.h>
-#include <SensirionI2cScd4x.h>
+#include <stdlib.h>
-#include <Wire.h>
 
-SensirionI2cScd4x sensor;
-
-int error;
-static char errorMessage[64];
-
-const char *config_file_path = "/config.json";
-long inactivity_delay;
-Config *config;
 WiFiClient wifi_client;
 PubSubClient mqtt_client(wifi_client);
+SensirionI2cScd4x sensor;
 
-int check_error(int error) {
+int error_code;
-    if (error) {
+char error_msg[64];
-        Serial.println("Error while initializing sensor");
+const char *config_file_path = "/config.json";
-        errorToString(error, errorMessage, sizeof errorMessage);
+Config *config;
-        return 1;
-    }
-    return 0;
-}
 
 void setup() {
     Serial.begin(9600);
-    Wire.begin();
+    config = (Config *)malloc(sizeof(Config));
-    sensor.begin(Wire, SCD41_I2C_ADDR_62);
+
-    error = sensor.wakeUp();
+    if (!load_config_file(config_file_path, config))
-    error = sensor.stopPeriodicMeasurement();
+        Serial.println("ERROR: The config file could not be loaded");
-    error = sensor.reinit();
+
-    error = sensor.startPeriodicMeasurement();
+    connect_wlan(config);
-    inactivity_delay = 60000;
+    connect_mqtt(mqtt_client, config);
+    initialize_sensor(sensor, error_code, error_msg);
 }
 
 void loop() {
-    uint16_t co2_concentration = 0.0;
+    float data[3];
-    float temperature = 0.0;
-    float humidity = 0.0;
-    bool data_available = false;
 
-    error = sensor.getDataReadyStatus(data_available);
+    read_values(sensor, data, error_code, error_msg);
-    error = sensor.readMeasurement(co2_concentration, temperature, humidity);
+    mqtt_transfer(mqtt_client, config, data);
-
+    delay(config->sleep_time);
-    if (data_available) {
-        Serial.print("CO2 concentration [ppm]: ");
-        Serial.print(co2_concentration);
-        Serial.println();
-        Serial.print("Temperature [°C]: ");
-        Serial.print(temperature);
-        Serial.println();
-        Serial.print("Relative Humidity [RH]: ");
-        Serial.print(humidity);
-        Serial.println();
-    } else {
-        Serial.println(".");
-    }
-
-    delay(inactivity_delay);
 }

src/sensor.cpp

@@ -0,0 +1,49 @@
+#include "sensor.h"
+#include <Wire.h>
+
+// TODO Trigger a reset when an error occurs
+void handle_error(int code, char *msg) {
+    if (code) {
+        errorToString(code, msg, sizeof msg);
+        exit(1);
+    }
+}
+
+void initialize_sensor(SensirionI2cScd4x &sensor, int error_code,
+                       char *error_msg) {
+    Wire.begin();
+    sensor.begin(Wire, SCD41_I2C_ADDR_62);
+    Serial.println("Starting sensor initialization");
+
+    error_code = sensor.wakeUp();
+    handle_error(error_code, error_msg);
+    error_code = sensor.stopPeriodicMeasurement();
+    handle_error(error_code, error_msg);
+    error_code = sensor.reinit();
+    handle_error(error_code, error_msg);
+    error_code = sensor.startPeriodicMeasurement();
+    handle_error(error_code, error_msg);
+
+    Serial.println("The sensor was initialized properly");
+};
+
+void read_values(SensirionI2cScd4x &sensor, float *data, int error_code,
+                 char *error_msg) {
+    bool data_available = false;
+    short unsigned int co2_concentration = 0.0;
+
+    error_code = sensor.getDataReadyStatus(data_available);
+    handle_error(error_code, error_msg);
+
+    while (!data_available) {
+        delay(100);
+        error_code = sensor.getDataReadyStatus(data_available);
+        handle_error(error_code, error_msg);
+    }
+
+    Serial.println("Data fetched from the sensor");
+
+    error_code = sensor.readMeasurement(co2_concentration, data[1], data[2]);
+    data[0] = co2_concentration;
+    handle_error(error_code, error_msg);
+}

src/wlan.cpp

@@ -17,16 +17,25 @@ void connect_wlan(Config *config) {
         delay(1000);
         Serial.print(".");
     }
+    Serial.println("");
     Serial.println("WiFi connected");
 }
 
 void connect_mqtt(PubSubClient &client, Config *config) {
-    if (!client.connected())
+    bool connection;
     client.setServer(config->mqtt_host, config->mqtt_port);
-    if (client.connect(config->device_id, config->mqtt_user,
+
-                       config->mqtt_password)) {
+    while (!client.connected()) {
+        connection = client.connect(config->device_id, config->mqtt_user,
+                                    config->mqtt_password);
+        if (connection) {
             Serial.println("MQTT connected");
             client.subscribe(config->topic);
+        } else {
+            Serial.println("MQTT failed to connect");
+            Serial.println(client.state());
+            delay(5000);
+        }
     }
 }
 
@@ -38,15 +47,15 @@ void disconnect_mqtt(PubSubClient &client, const char *topic) {
 
 size_t construct_json(float *data, char *buffer, int buffer_size) {
     JsonDocument json;
-    json["temperature"] = data[0];
+    json["co2_concentration"] = data[0];
-    json["humidity"] = data[1];
+    json["temperature"] = data[1];
+    json["humidity"] = data[2];
     size_t payload_size = serializeJson(json, buffer, buffer_size);
     return payload_size;
 }
 
 void mqtt_transfer(PubSubClient &client, Config *config, float *data) {
     char buffer[100];
-    connect_mqtt(client, config);
     size_t payload_size = construct_json(data, buffer, 100);
     client.publish(config->topic, buffer, payload_size);
     Serial.println("Data transferred successfully");