Update README

.gitignore

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

README.org

@@ -1,13 +1,44 @@
 * Homeostasis
 
-Temperature, air humidity and soil humidity sensor that communicates via MQTT. The project is implemented using a Wemos D1 mini board with the following addons:
+Temperature, air humidity and soil humidity sensor that communicates via MQTT. The project is implemented using a Wemos D1 mini board with the following components:
 
-- DHT11 temperature and humidity
+- DHT22 temperature and humidity sensor
 - FC-28 soil hygrometer sensor
 - Battery shield
 - 3.7V 1000mAh Lithium battery
 
+The sensor captures the data every 15 minutes and sends it to a MQTT broker and then enters deep sleep, it is important to save power as the device runs off a battery.
+
+#+ATTR_HTML: :width 60%
+[[./result.png]]
+
 ** Pinout of the board
 
-#+ATTR_HTML: :width 50%
+#+ATTR_HTML: :width 40%
 [[./pinout.png]]
+** Dependencies
+- [[https://github.com/adafruit/DHT-sensor-library][Adafruit DHT sensor library]]
+- [[https://github.com/adafruit/Adafruit_Sensor][Adafruit Unified Sensor Driver]]
+- [[https://github.com/knolleary/pubsubclient][PubSubClient]]
+- [[https://github.com/bblanchon/ArduinoJson][ArduinoJSON]]
+** Deployment
+
+The software uses the Arduino framework and the development environment of [[https://platformio.org/][PlatformIO]], which offers better tools than the Arduino IDE.
+
+1. Upload the configuration file to the board:
+
+#+begin_src shell
+pio run -t uploadfs
+#+end_src
+
+2. Compile the project
+
+#+begin_src shell
+pio run -t compile
+#+end_src
+
+3. Upload firmware
+
+#+begin_src shell
+pio run -t upload
+#+end_src

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 +1,27 @@
+#ifndef CONFIG_H_
+#define CONFIG_H_
+
+#include "FS.h"
+#include "LittleFS.h"
+#include <ArduinoJson.h>
+
+typedef struct {
+  const char *ssid;
+  const char *psk;
+  const char *mqtt_host;
+  const char *mqtt_user;
+  const char *mqtt_password;
+  const char *topic;
+  const char *device_id;
+  int mqtt_port;
+  long sleep_time;
+  int connection_attempts;
+} Config;
+
+void initialize_config(Config *config, StaticJsonDocument<512> json);
+
+bool load_config_file(const char *file_path, Config *config);
+
+long minutes_to_microseconds(int minutes);
+
+#endif // CONFIG_H_

include/wlan.h

@@ -0,0 +1,16 @@
+#ifndef WLAN_H
+#define WLAN_H
+
+#include "config.h"
+#include <ESP8266WiFi.h>
+#include <PubSubClient.h>
+
+void initial_connection(const char *ssid, const char *psk);
+void connect_wlan(Config *config);
+void connect_mqtt(PubSubClient &client, Config *config);
+void disconnect_mqtt(PubSubClient &client, const char *topic);
+size_t construct_json(float *data, char *buffer, int buffer_size);
+void mqtt_transfer(PubSubClient &client, Config *config, float *data);
+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 +1,30 @@
+#include "config.h"
+
+void initialize_config(Config *config, StaticJsonDocument<512> json) {
+  config->ssid = strdup(json["ssid"]);
+  config->psk = strdup(json["psk"]);
+  config->mqtt_host = strdup(json["mqtt_host"]);
+  config->mqtt_user = strdup(json["mqtt_user"]);
+  config->mqtt_password = strdup(json["mqtt_password"]);
+  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->connection_attempts = json["connection_attempts"];
+}
+
+bool load_config_file(const char *file_path, 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;
+  initialize_config(config, json);
+  return true;
+}
+
+long minutes_to_microseconds(int minutes) { return (minutes * 6e7); }

src/main.cpp

@@ -1,15 +1,15 @@
+#include "config.h"
 #include "wlan.h"
 #include <Arduino.h>
 #include <DHT.h>
 
-#define DHTTYPE DHT11
+#define DHTTYPE DHT22
 #define DHTPIN 4
 DHT dht(DHTPIN, DHTTYPE);
 
 const int fc28_pin = A0;
-const int max_connection_attempts = 60;
+const char *config_file_path = "/config.json";
-const char *topic = "homeostasis/room";
+Config *config;
-const char *device_id = "homeostasis";
 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);
+  config = (Config *)malloc(sizeof(Config));
+  if (!load_config_file(config_file_path, config))
+    Serial.println("ERROR: The config file could not be loaded");
+  connect_wlan(config);
 }
 
 void loop() {
@@ -30,8 +33,9 @@ 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, data);
   }
-  disconnect_mqtt(mqtt_client, topic);
+  disconnect_mqtt(mqtt_client, config->topic);
-  enter_deep_sleep(false);
+  free(config);
+  enter_deep_sleep(false, config->sleep_time);
 }

src/wlan.cpp

@@ -1,21 +1,20 @@
 #include "wlan.h"
-#include "credentials.h"
 #include <ArduinoJson.h>
 
-void initial_connection() {
+void initial_connection(const char *ssid, const char *psk) {
-  WiFi.begin(SSID, PSK);
+  WiFi.begin(ssid, psk);
   WiFi.persistent(true);
   WiFi.setAutoConnect(true);
   WiFi.setAutoReconnect(true);
 }
 
-void connect_wlan(const int max_retries) {
+void connect_wlan(Config *config) {
-  if (WiFi.SSID() != SSID)
+  if (WiFi.SSID() != config->ssid)
-    initial_connection();
+    initial_connection(config->ssid, config->psk);
   int retries = 0;
   while (WiFi.status() != WL_CONNECTED) {
-    if (retries == max_retries)
+    if (retries == config->connection_attempts)
-      enter_deep_sleep(true);
+      enter_deep_sleep(true, config->sleep_time);
     retries++;
     delay(1000);
     Serial.print(".");
@@ -23,13 +22,13 @@ 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, Config *config) {
-                  const char *topic) {
   if (!client.connected())
-    client.setServer(MQTT_HOST, MQTT_PORT);
+    client.setServer(config->mqtt_host, config->mqtt_port);
-  if (client.connect(device_id, MQTT_USER, MQTT_PASSWORD)) {
+  if (client.connect(config->device_id, config->mqtt_user,
+                     config->mqtt_password)) {
     Serial.println("MQTT connected");
-    client.subscribe(topic);
+    client.subscribe(config->topic);
   }
 }
 
@@ -48,18 +47,17 @@ 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, Config *config, float *data) {
-                   const char *topic, float *data) {
   char buffer[100];
-  connect_mqtt(client, device_id, topic);
+  connect_mqtt(client, config);
   size_t payload_size = construct_json(data, buffer, 100);
-  client.publish(topic, buffer, payload_size);
+  client.publish(config->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);
 }

src/wlan.h

@@ -1,20 +0,0 @@
-#ifndef WLAN_H
-#define WLAN_H
-
-#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,
-                  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,
-                   const char *topic, float *data);
-void enter_deep_sleep(bool wifi_timeout);
-
-#endif /* WLAN_H */