Update README

.gitignore

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

README.org

@@ -1,20 +1,20 @@
 * 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 components:
+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:
 
-- DHT22 temperature and humidity sensor
+- DHT11 temperature and humidity
 - 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%
+#+ATTR_HTML: :width 50%
 [[./result.png]]
 
 ** Pinout of the board
 
-#+ATTR_HTML: :width 40%
+#+ATTR_HTML: :width 50%
 [[./pinout.png]]
 ** Dependencies
 - [[https://github.com/adafruit/DHT-sensor-library][Adafruit DHT sensor library]]
@@ -23,22 +23,4 @@ The sensor captures the data every 15 minutes and sends it to a MQTT broker and
 - [[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.
+The software uses the Arduino framework and the development environment of [[https://platformio.org/][PlatformIO]], which offers better tools that 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

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

flake.lock

@@ -1,23 +1,37 @@
 {
   "nodes": {
-    "nixpkgs": {
+    "flake-utils": {
       "locked": {
-        "lastModified": 1773046814,
+        "lastModified": 1676283394,
-        "narHash": "sha256-3CEw64UyzEk5QjfbcXNIl4TfmIpa2oY+duuo6aiawcU=",
+        "narHash": "sha256-XX2f9c3iySLCw54rJ/CZs+ZK6IQy7GXNY4nSOyu2QG4=",
-        "owner": "NixOS",
+        "owner": "numtide",
-        "repo": "nixpkgs",
+        "repo": "flake-utils",
-        "rev": "0c6c0dd2469abaa216599bb19bbf77a328af6564",
+        "rev": "3db36a8b464d0c4532ba1c7dda728f4576d6d073",
         "type": "github"
       },
       "original": {
-        "owner": "NixOS",
+        "owner": "numtide",
-        "ref": "nixos-unstable-small",
+        "repo": "flake-utils",
-        "repo": "nixpkgs",
         "type": "github"
       }
     },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1677229269,
+        "narHash": "sha256-awE2w6oi9rzQ8qj1lwKEDm6qIA0a239fiB+AyPjXR2w=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "7d0ed7f2e5aea07ab22ccb338d27fbe347ed2f11",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "type": "indirect"
+      }
+    },
     "root": {
       "inputs": {
+        "flake-utils": "flake-utils",
         "nixpkgs": "nixpkgs"
       }
     }

flake.nix

@@ -1,25 +1,14 @@
 {
-  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable-small";
+  description = "";
 
-  outputs =
+  inputs.flake-utils.url = "github:numtide/flake-utils";
-    { self, nixpkgs, ... }:
+
-    let
+  outputs = { self, nixpkgs, flake-utils }:
-      system = "x86_64-linux";
+    flake-utils.lib.eachDefaultSystem
-    in
+      (system:
+        let pkgs = nixpkgs.legacyPackages.${system}; in
         {
-      devShells."${system}".default =
+          devShell = import ./shell.nix { inherit pkgs; };
-        let
+        }
-          pkgs = import nixpkgs {
+      );
-            inherit system;
-          };
-        in
-        pkgs.mkShell {
-          packages = with pkgs; [
-            clang
-            platformio
-          ];
-
-          shellHook = "";
-        };
-    };
 }

include/config.h

@@ -1,24 +0,0 @@
-#ifndef CONFIG_H_
-#define CONFIG_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;
-    unsigned long sleep_time;
-} Config;
-
-void initialize_config(Config *config, JsonDocument json);
-
-bool load_config_file(const char *file_path, Config *config);
-
-long minutes_to_milliseconds(int minutes);
-
-#endif // CONFIG_H_

include/sensor.h

@@ -1,10 +0,0 @@
-#ifndef SENSOR_H_
-#define SENSOR_H_
-
-#include <DHT.h>
-
-void initialize_sensor(DHT &sensor);
-
-void read_values(DHT &sensor, float *data);
-
-#endif // SENSOR_H_

include/wlan.h

@@ -1,29 +1,20 @@
 #ifndef WLAN_H
 #define WLAN_H
 
-#include "config.h"
+#include <ESP8266WiFi.h>
-#include <AsyncMqttClient.h>
+#include <PubSubClient.h>
-#include <Ticker.h>
-#include <WiFi.h>
 
-static AsyncMqttClient mqtt_client;
+const int SLEEP_TIME = 900000000;
-static Ticker mqtt_connection_timer, wlan_connection_timer;
+const int WIFI_TIMEOUT = 10000;
-extern Config *config;
-
-void initialize_wlan();
-
-void initialize_mqtt();
-
-void connect_wlan();
-
-void connect_mqtt();
-
-void wlan_connection_handler(WiFiEvent_t event);
-
-void on_mqtt_disconnection(AsyncMqttClientDisconnectReason reason);
 
+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,
-void mqtt_transfer(float *data);
+                   const char *topic, float *data);
+void enter_deep_sleep(bool wifi_timeout);
 
 #endif /* WLAN_H */

platformio.ini

@@ -9,13 +9,11 @@
 ; https://docs.platformio.org/page/projectconf.html
 
 [env:d1_mini]
-platform = espressif32
+platform = espressif8266
-board = wemos_d1_mini32
+board = d1_mini
-board_build.filesystem = littlefs
 framework = arduino
-monitor_filters = esp32_exception_decoder
 lib_deps =
   adafruit/DHT sensor library@^1.4.4
   adafruit/Adafruit Unified Sensor@^1.1.9
-  marvinroger/AsyncMqttClient@^0.9.0
+  knolleary/PubSubClient@^2.8
-  bblanchon/ArduinoJson@^7.4.1
+  bblanchon/ArduinoJson@^6.21.1

shell.nix

@@ -0,0 +1,5 @@
+{ pkgs ? import <nixpkgs> { } }:
+
+with pkgs;
+
+mkShell { buildInputs = [ platformio clang ]; }

src/config.cpp

@@ -1,30 +0,0 @@
-#include "config.h"
-#include "LittleFS.h"
-
-void initialize_config(Config *config, JsonDocument 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_milliseconds(json["sleep_time"]);
-}
-
-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;
-    JsonDocument json;
-    DeserializationError err = deserializeJson(json, config_file);
-    if (err)
-        return false;
-    initialize_config(config, json);
-    return true;
-}
-
-long minutes_to_milliseconds(int minutes) { return (minutes * 6e4); }

src/main.cpp

@@ -1,36 +1,37 @@
-#include "config.h"
-#include "sensor.h"
 #include "wlan.h"
 #include <Arduino.h>
 #include <DHT.h>
 
-DHT dht(4, DHT22);
+#define DHTTYPE DHT11
+#define DHTPIN 4
+DHT dht(DHTPIN, DHTTYPE);
 
-const char *config_file_path = "/config.json";
+const int fc28_pin = A0;
-Config *config;
+const int max_connection_attempts = 60;
+const char *topic = "homeostasis/room";
+const char *device_id = "homeostasis";
+WiFiClient wifi_client;
+PubSubClient mqtt_client(wifi_client);
 
-float data[2];
+bool check_valid_value(float value) {
-unsigned long previous_millis = 0;
+  return (!isnan(value) && value >= 0 && value <= 100);
+}
 
 void setup() {
   Serial.begin(9600);
-    config = (Config *)malloc(sizeof(Config));
+  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");
-
-    initialize_wlan();
-    initialize_mqtt();
-    connect_wlan();
-    initialize_sensor(dht);
 }
 
 void loop() {
-    unsigned long current_millis = millis();
+  float temperature = dht.readTemperature();
-
+  float humidity = dht.readHumidity();
-    if (current_millis - previous_millis >= config->sleep_time) {
+  int analog_val = analogRead(fc28_pin);
-        previous_millis = current_millis;
+  int soil_percentage = map(analog_val, 0, 1023, 0, 100);
-        read_values(dht, data);
+  float data[3] = {temperature, humidity, static_cast<float>(soil_percentage)};
-        mqtt_transfer(data);
+  if (check_valid_value(temperature) && check_valid_value(humidity)) {
+    mqtt_transfer(mqtt_client, device_id, topic, data);
   }
+  disconnect_mqtt(mqtt_client, topic);
+  enter_deep_sleep(false);
 }

src/sensor.cpp

@@ -1,13 +0,0 @@
-#include "sensor.h"
-
-void initialize_sensor(DHT &sensor) { sensor.begin(); }
-
-void read_values(DHT &sensor, float *data) {
-    float temperature = sensor.readTemperature();
-    float humidity = sensor.readHumidity();
-
-    Serial.println("Data fetched from the sensor");
-
-    data[0] = temperature;
-    data[1] = humidity;
-}

src/wlan.cpp

@@ -1,57 +1,65 @@
 #include "wlan.h"
+#include "credentials.h"
+#include <ArduinoJson.h>
 
-void initialize_wlan() { WiFi.onEvent(wlan_connection_handler); }
+void initial_connection() {
-
+  WiFi.begin(SSID, PSK);
-void initialize_mqtt() {
+  WiFi.persistent(true);
-    mqtt_client.onDisconnect(on_mqtt_disconnection);
+  WiFi.setAutoConnect(true);
-    mqtt_client.setServer(config->mqtt_host, config->mqtt_port);
+  WiFi.setAutoReconnect(true);
-    mqtt_client.setCredentials(config->mqtt_user, config->mqtt_password);
-    Serial.println("MQTT initialization complete");
 }
 
-void connect_wlan() { WiFi.begin(config->ssid, config->psk); }
+void connect_wlan(const int max_retries) {
-
+  if (WiFi.SSID() != SSID)
-void connect_mqtt() {
+    initial_connection();
-    Serial.println("Connecting to MQTT");
+  int retries = 0;
-    mqtt_client.connect();
+  while (WiFi.status() != WL_CONNECTED) {
-}
+    if (retries == max_retries)
-
+      enter_deep_sleep(true);
-void wlan_connection_handler(WiFiEvent_t event) {
+    retries++;
-    Serial.printf("[WiFi-event] event: %d\n", event);
+    delay(1000);
-    switch (event) {
+    Serial.print(".");
-    case SYSTEM_EVENT_STA_GOT_IP:
+  }
   Serial.println("WiFi connected");
-        connect_mqtt();
+}
-        break;
+
-    case SYSTEM_EVENT_STA_DISCONNECTED:
+void connect_mqtt(PubSubClient &client, const char *device_id,
-        Serial.println("WiFi disconnected");
+                  const char *topic) {
-        mqtt_connection_timer.detach();
+  if (!client.connected())
-        wlan_connection_timer.once(2, connect_wlan);
+    client.setServer(MQTT_HOST, MQTT_PORT);
-        break;
+  if (client.connect(device_id, MQTT_USER, MQTT_PASSWORD)) {
+    Serial.println("MQTT connected");
+    client.subscribe(topic);
   }
 }
 
-void on_mqtt_disconnection(AsyncMqttClientDisconnectReason reason) {
+void disconnect_mqtt(PubSubClient &client, const char *topic) {
-    Serial.println("MQTT disconnected");
+  Serial.println("Disconnecting MQTT");
-
+  client.unsubscribe(topic);
-    if (WiFi.isConnected()) {
+  client.disconnect();
-        mqtt_connection_timer.once(2, connect_mqtt);
-    }
 }
 
 size_t construct_json(float *data, char *buffer, int buffer_size) {
-    JsonDocument json;
+  StaticJsonDocument<100> json;
   json["temperature"] = data[0];
   json["humidity"] = data[1];
+  json["soil_humidity"] = data[2];
   size_t payload_size = serializeJson(json, buffer, buffer_size);
   return payload_size;
 }
 
-void mqtt_transfer(float *data) {
+void mqtt_transfer(PubSubClient &client, const char *device_id,
+                   const char *topic, float *data) {
   char buffer[100];
+  connect_mqtt(client, device_id, topic);
   size_t payload_size = construct_json(data, buffer, 100);
-    uint16_t response =
+  client.publish(topic, buffer, payload_size);
-        mqtt_client.publish(config->topic, 2, true, buffer, payload_size);
-    if (response)
   Serial.println("Data transferred successfully");
 }
+
+void enter_deep_sleep(bool wifi_timeout) {
+  Serial.println("Entering deep sleep");
+  if (wifi_timeout)
+    WiFi.disconnect();
+  ESP.deepSleep(SLEEP_TIME, WAKE_RF_DEFAULT);
+}