+ show startup and Wi-Fi status on the OLED

+ fetch data immediately after connecting
+ empty display and a shorter retry interval for failed requests
~ poll normally every 10 seconds and use the configured local endpoint
~ keep previous readings visible and mark them as outdated on failure
~ set the font before drawing status text and tidy serial messages
- generic failure screen and placeholder network settings

awair_data_grabber/awair_data_grabber.ino

@@ -13,12 +13,13 @@
 #define OLED_SCL 14
 #define OLED_SDA 12
 
-#define UPDATE_INTERVAL_MS 1000
+#define UPDATE_INTERVAL_MS 10000
+#define SHORT_UPDATE_INTERVAL_MS (UPDATE_INTERVAL_MS / 10)
 
-#define SERVER_URL "http://awair-server/air-data/latest"
+#define SERVER_URL "http://[IP_ADDRESS]/air-data/latest"
 
-#define SSID "-"
-#define PASSWD "-"
+#define SSID "[SSID]"
+#define PASSWD "[PASS]"
 
 WiFiClient client;
 HTTPClient http;
@@ -80,13 +81,21 @@ class Panel{
       panel.begin();
     }
 
-    void show_failed(void){
-      panel.clearBuffer();
+    void show_outdated(void){
       panel.setFont(u8g2_font_ncenB08_tr);
-      panel.drawStr(0, 10, "Something failed");
+      panel.drawStr(71, 9, "(outdated)");
       panel.sendBuffer();
     }
 
+    void print_header(const char* msg){
+      panel.clearBuffer();
+      panel.setFont(u8g2_font_ncenB08_tr);
+      panel.drawStr(0, 9, msg);
+      panel.sendBuffer();
+    }
+
+    void print_empty_data(){ update({}); }
+
     void update(const AwairData& data){
       char buffer[16];
 
@@ -175,15 +184,31 @@ AwairData data;
 
 void setup() {
   Serial.begin(115200);
-  
+
   panel.begin();
+  panel.print_header("Starting...");
 
   http.setTimeout(3000);
 
-  WiFi.begin(SSID, PASSWD);
-  while(WiFi.status() != WL_CONNECTED) delay(100);
+  Serial.println("\nConnecting to WiFi...");
+  panel.print_header("Connecting to WiFi...");
 
-  Serial.println("Connected!");
+  WiFi.begin(SSID, PASSWD);
+  while(WiFi.status() != WL_CONNECTED){
+    delay(100);
+    Serial.print(".");
+  }
+
+  Serial.println("\nConnected!");
+  panel.print_header("Connected to WiFi!");
+
+  if(request_data(&data) != 0){ panel.print_empty_data(); }
+  else{
+    Serial.println("Got new data -> Updating...");
+    panel.update(data);
+    data.reset_updated();
+  }
+  delay(SHORT_UPDATE_INTERVAL_MS);
 }
 
 void loop() {
@@ -195,18 +220,23 @@ void loop() {
   start = current;
   */
 
+  size_t update_interval = UPDATE_INTERVAL_MS;
+
   if(WiFi.status() != WL_CONNECTED){ delay(100); return; }
 
   Serial.println("Requesting data...");
-  if(request_data(&data) != 0){ panel.show_failed(); }
-
-  if(data.has_updated()){
+  if(request_data(&data) != 0){
+    panel.show_outdated();
+    update_interval = SHORT_UPDATE_INTERVAL_MS;
+  }
+  else if(data.has_updated()){
     Serial.println("Got new data -> Updating...");
     panel.update(data);
     data.reset_updated();
   }
-  else Serial.println("Got data but nothing new!");
+  else Serial.println("No new data!");
 
-  Serial.println("---------- ---------- ----------\n");
-  delay(UPDATE_INTERVAL_MS); // simple delay is enough <- no state machine
+  Serial.println("\n---------- ---------- ----------\n");
+  
+  delay(update_interval); // simple delay is enough <- no state machine
 }