Load credentials and settings from config file

.gitignore

@@ -1,2 +1,3 @@
 .pio
 src/credentials.h
+data/config.json

data/example.json

@@ -0,0 +1,12 @@
+{
+  "ssid": "",
+  "psk": "",
+  "mqtt_host": "",
+  "mqtt_user": "",
+  "mqtt_password": "",
+  "mqtt_port": 1883,
+  "mqtt_topic": "",
+  "device_id": "",
+  "sleep_time": 30,
+  "connection_attempts": 60
+}

include/config.h

@@ -0,0 +1,24 @@
+#ifndef CONFIG_H_
+#define CONFIG_H_
+
+#include "FS.h"
+#include "LittleFS.h"
+
+struct Config {
+  const char *ssid;
+  const char *psk;
+  const char *mqtt_host;
+  const char *mqtt_user;
+  const char *mqtt_password;
+  int mqtt_port;
+  const char *topic;
+  const char *device_id;
+  long sleep_time;
+  int connection_attempts;
+};
+
+bool load_config_file(const char *file_path, struct Config &config);
+
+long minutes_to_microseconds(int minutes);
+
+#endif // CONFIG_H_

include/wlan.h

@@ -4,17 +4,19 @@
 #include <ESP8266WiFi.h>
 #include <PubSubClient.h>
 
-const int SLEEP_TIME = 900000000;
-const int WIFI_TIMEOUT = 10000;
-
-void initial_connection();
-void connect_wlan(const int max_retries);
-void connect_mqtt(PubSubClient &client, const char *device_id,
+void initial_connection(const char *ssid, const char *psk);
+void connect_wlan(const char *ssid, const char *psk, const int max_retries,
+                  const int sleep_time);
+void connect_mqtt(PubSubClient &client, const char *mqtt_host,
+                  const int mqtt_port, const char *mqtt_user,
+                  const char *mqtt_password, const char *device_id,
                   const char *topic);
 void disconnect_mqtt(PubSubClient &client, const char *topic);
 size_t construct_json(float *data, char *buffer, int buffer_size);
-void mqtt_transfer(PubSubClient &client, const char *device_id,
+void mqtt_transfer(PubSubClient &client, const char *mqtt_host,
+                   const int mqtt_port, const char *mqtt_user,
+                   const char *mqtt_password, const char *device_id,
                    const char *topic, float *data);
-void enter_deep_sleep(bool wifi_timeout);
+void enter_deep_sleep(bool wifi_timeout, int sleep_time);
 
 #endif /* WLAN_H */

platformio.ini

@@ -11,6 +11,7 @@
 [env:d1_mini]
 platform = espressif8266
 board = d1_mini
+board_build.filesystem = littlefs
 framework = arduino
 lib_deps =
   adafruit/DHT sensor library@^1.4.4

src/config.cpp

@@ -0,0 +1,29 @@
+#include "config.h"
+#include <ArduinoJson.h>
+
+bool load_config_file(const char *file_path, struct Config &config) {
+  if (!LittleFS.begin())
+    return false;
+  File config_file = LittleFS.open(file_path, "r");
+  if (!config_file)
+    return false;
+  StaticJsonDocument<512> json;
+  DeserializationError err = deserializeJson(json, config_file);
+  if (err)
+    return false;
+  config = {
+      .ssid = json["ssid"],
+      .psk = json["psk"],
+      .mqtt_host = json["mqtt_host"],
+      .mqtt_user = json["mqtt_user"],
+      .mqtt_password = json["mqtt_password"],
+      .mqtt_port = json["mqtt_port"],
+      .topic = json["mqtt_topic"],
+      .device_id = json["device_id"],
+      .sleep_time = minutes_to_microseconds(json["sleep_time"]),
+      .connection_attempts = json["connection_attempts"],
+  };
+  return true;
+}
+
+long minutes_to_microseconds(int minutes) { return (minutes * 6e7); }

src/main.cpp

@@ -1,3 +1,4 @@
+#include "config.h"
 #include "wlan.h"
 #include <Arduino.h>
 #include <DHT.h>
@@ -7,9 +8,8 @@
 DHT dht(DHTPIN, DHTTYPE);
 
 const int fc28_pin = A0;
-const int max_connection_attempts = 60;
-const char *topic = "homeostasis/room";
-const char *device_id = "homeostasis";
+const char *config_file_path = "/config.json";
+Config config;
 WiFiClient wifi_client;
 PubSubClient mqtt_client(wifi_client);
 
@@ -20,7 +20,10 @@ bool check_valid_value(float value) {
 void setup() {
   Serial.begin(9600);
   dht.begin();
-  connect_wlan(max_connection_attempts);
+  if (!load_config_file(config_file_path, config))
+    Serial.println("ERROR: The config file could not be loaded");
+  connect_wlan(config.ssid, config.psk, config.connection_attempts,
+               config.sleep_time);
 }
 
 void loop() {
@@ -30,8 +33,11 @@ void loop() {
   int soil_percentage = map(analog_val, 0, 1023, 0, 100);
   float data[3] = {temperature, humidity, static_cast<float>(soil_percentage)};
   if (check_valid_value(temperature) && check_valid_value(humidity)) {
-    mqtt_transfer(mqtt_client, device_id, topic, data);
+    mqtt_transfer(mqtt_client, config.mqtt_host, config.mqtt_port,
+                  config.mqtt_user, config.mqtt_password, config.device_id,
+                  config.topic, data);
   }
-  disconnect_mqtt(mqtt_client, topic);
-  enter_deep_sleep(false);
+  disconnect_mqtt(mqtt_client, config.topic);
+  enter_deep_sleep(false, config.sleep_time);
+  delay(60000);
 }

src/wlan.cpp

@@ -1,21 +1,21 @@
 #include "wlan.h"
-#include "credentials.h"
 #include <ArduinoJson.h>
 
-void initial_connection() {
-  WiFi.begin(SSID, PSK);
+void initial_connection(const char *ssid, const char *psk) {
+  WiFi.begin(ssid, psk);
   WiFi.persistent(true);
   WiFi.setAutoConnect(true);
   WiFi.setAutoReconnect(true);
 }
 
-void connect_wlan(const int max_retries) {
-  if (WiFi.SSID() != SSID)
-    initial_connection();
+void connect_wlan(const char *ssid, const char *psk, const int max_retries,
+                  const int sleep_time) {
+  if (WiFi.SSID() != ssid)
+    initial_connection(ssid, psk);
   int retries = 0;
   while (WiFi.status() != WL_CONNECTED) {
     if (retries == max_retries)
-      enter_deep_sleep(true);
+      enter_deep_sleep(true, sleep_time);
     retries++;
     delay(1000);
     Serial.print(".");
@@ -23,11 +23,13 @@ void connect_wlan(const int max_retries) {
   Serial.println("WiFi connected");
 }
 
-void connect_mqtt(PubSubClient &client, const char *device_id,
+void connect_mqtt(PubSubClient &client, const char *mqtt_host,
+                  const int mqtt_port, const char *mqtt_user,
+                  const char *mqtt_password, const char *device_id,
                   const char *topic) {
   if (!client.connected())
-    client.setServer(MQTT_HOST, MQTT_PORT);
-  if (client.connect(device_id, MQTT_USER, MQTT_PASSWORD)) {
+    client.setServer(mqtt_host, mqtt_port);
+  if (client.connect(device_id, mqtt_user, mqtt_password)) {
     Serial.println("MQTT connected");
     client.subscribe(topic);
   }
@@ -48,18 +50,21 @@ size_t construct_json(float *data, char *buffer, int buffer_size) {
   return payload_size;
 }
 
-void mqtt_transfer(PubSubClient &client, const char *device_id,
+void mqtt_transfer(PubSubClient &client, const char *mqtt_host,
+                   const int mqtt_port, const char *mqtt_user,
+                   const char *mqtt_password, const char *device_id,
                    const char *topic, float *data) {
   char buffer[100];
-  connect_mqtt(client, device_id, topic);
+  connect_mqtt(client, mqtt_host, mqtt_port, mqtt_user, mqtt_password,
+               device_id, topic);
   size_t payload_size = construct_json(data, buffer, 100);
   client.publish(topic, buffer, payload_size);
   Serial.println("Data transferred successfully");
 }
 
-void enter_deep_sleep(bool wifi_timeout) {
+void enter_deep_sleep(bool wifi_timeout, int sleep_time) {
   Serial.println("Entering deep sleep");
   if (wifi_timeout)
     WiFi.disconnect();
-  ESP.deepSleep(SLEEP_TIME, WAKE_RF_DEFAULT);
+  ESP.deepSleep(sleep_time, WAKE_RF_DEFAULT);
 }