feat: add NIC specific part of MAC address as suffix to SSID (#15)

Co-authored-by: Alexander Bessman <[email protected]>

Author: marcnause

docs/esptool.md

@@ -88,4 +88,4 @@ You should see something like this:
     Leaving...
     Hard resetting via RTS pin...
 
-Now pull the ESP-01's GPIO_0 pin high and reset it. If the new firmware was flashed successfully, it will start broadcasting an SSID called "PSLab".
+Now pull the ESP-01's GPIO_0 pin high and reset it. If the new firmware was flashed successfully, it will start broadcasting an SSID starting with "PSLab_" followed by the last three octets of the MAC address of the ESP-01 (e.g. "PSLab_0DCE2F").

src/ESP01Firmware/ESP01Firmware.ino

@@ -13,7 +13,7 @@ void setup() {
 
   WiFi.setSleepMode(WIFI_NONE_SLEEP);
 
-  WiFi.softAP(ssid, password);
+  WiFi.softAP(ssid + get_suffix(), password);
 
   server.begin();
 }
@@ -35,4 +35,17 @@ void loop() {
     }
     client.stop();
   }
-}
+}
+
+/**
+ * @brief Return a suffix based on the NIC specific part of the MAC address
+ *
+ * @return The final three octets of the MAC address, prefixed with underscore
+ */
+String get_suffix() {
+  // Remove vendor ID
+  String mac = WiFi.macAddress().substring(9, 17);
+  // Remove colons
+  mac.replace(":", "");
+  return "_" + mac;
+}