Lets start ...

firmware/config.h

@@ -0,0 +1,13 @@
+#define DEBUG
+
+#define WIFI_PASSWORD "xxx"
+#define WIFI_SSID "xxx"
+
+#define SENSOR_TEMPERATURE 0
+#define SENSOR_HUMIDITY    1
+#define SENSOR_LIGHT       2
+
+#define UPDATE_INTERVAL 4
+#define STATUS_LED BUILTIN_LED
+
+

firmware/firmware.ino

@@ -1,9 +1,59 @@
-void setup() {
-  // put your setup code here, to run once:
 
+#include <ESP8266WiFi.h>
+#include "config.h"
+
+/**
+ * Whishlist:
+ * - Push sensor values to influxdb
+ * - Webserver for /metrics endpoint (Prometheus)
+ * - Show current sensor values over simple webpage
+ * - Push sensor values to various 3rd party services
+ * 
+ * - Auto-Reconnect for WIFI
+ * - Buffer sensor values if there is no WIFI connection
+ * - Configure weather station over http webinterface
+ * - If there are now WiFi credentials, open up an access point to configure it
+ */
+
+float currentSensorData[3] = {0.0, 0.0, 0.0};
+
+void connectToWiFi() {
+}
+bool checkWiFiConnection() {
+  return true;
+}
+
+void setup() {
+  #ifdef DEBUG
+    Serial.begin(115200);
+  #endif
+  
+  pinMode(STATUS_LED, OUTPUT);
+  connectToWiFi();
 }
 
 void loop() {
-  // put your main code here, to run repeatedly:
+  digitalWrite(STATUS_LED, LOW);
 
+  while (!checkWiFiConnection()) {
+    connectToWiFi();
+    delay(5000);
+  }
+  
+  currentSensorData[SENSOR_TEMPERATURE] = fetchTemperature();
+  currentSensorData[SENSOR_HUMIDITY] = fetchHumidity();
+  currentSensorData[SENSOR_LIGHT] = fetchLight();
+
+  #ifdef DEBUG
+    Serial.println("");
+    Serial.println("Current readings:");
+    Serial.println("Temperature: " + String(currentSensorData[SENSOR_TEMPERATURE]));
+    Serial.println("Humidity: " + String(currentSensorData[SENSOR_HUMIDITY]));
+    Serial.println("Light: " + String(currentSensorData[SENSOR_LIGHT]));
+  #endif
+
+  pushToInfluxDB(currentSensorData);
+  
+  
+  delay(UPDATE_INTERVAL*1000);
 }

firmware/influxdb.ino

@@ -0,0 +1,4 @@
+void pushToInfluxDB(float sensorValues[]) {
+  
+}
+

firmware/sensors.ino

@@ -0,0 +1,13 @@
+
+float fetchTemperature() {
+  return 22.5;
+}
+
+float fetchHumidity() {
+  return 60.0;
+}
+
+float fetchLight() {
+  return 2000.4;
+}
+