Updated/fixed unique MQTT Client ID generation

Author: epiller

src/ATT_ESP8266.h

@@ -150,10 +150,9 @@ void Device::debugPort(Stream &debugSerial, bool verbose) {
 
 // Generate Unique MQTT ID
 void Device::generateRandomID() {
-    String chipId = "arduino-";
-    chipId += ESP.getChipId();
+    sprintf(mqttId, "%s%i", "arduino-", ESP.getChipId());
     debugVerbose("Unique MQTT ID of Device:", ' ');
-    debugVerbose(randValue);
+    debugVerbose(mqttId);
 }
 
 // Initialization of everything. Run in setup(), only after defining everything else.

src/ATT_MKR1010.h

@@ -201,14 +201,13 @@ void Device::debugPort(Stream &debugSerial, bool verbose) {
 
 }
 
-// Generate Random MQTT ID - If two same IDs are on one broker, the connection drops
+// Generate Unique MQTT ID
 void Device::generateRandomID() {
-    randomSeed(analogRead(0));
-    long randValue = random(2147483647);
-    snprintf(mqttId, sizeof mqttId, "%s%dl", "arduino-", randValue);
-    debugVerbose("Generated Unique ID for this Device:", ' ');
-    debugVerbose("arduino", '-');
-    debugVerbose(randValue);
+    byte mac[6];
+    WiFi.macAddress(mac);
+    sprintf(mqttId, "arduino-%2X%2X%2X%2X", mac[3], mac[2], mac[1], mac[0]);
+    debugVerbose("Unique MQTT ID of Device:", ' ');
+    debugVerbose(mqttId);
 }
 
 // Initialization of everything. Run in setup(), only after defining everything else.