diff --git a/firmware/firmware.ino b/firmware/firmware.ino
index 9f73bdb..9303017 100644
--- a/firmware/firmware.ino
+++ b/firmware/firmware.ino
@@ -18,7 +18,7 @@ String deviceName;
 
 const char broker[] = "192.168.69.106";
 int        port     = 1883;
-const char topic[]  = "iot/airmega/speed";
+String topic; // Changed from const char[]
 #define QOS_2 2
 
 void (* resetFunc) (void) = 0;
@@ -41,6 +41,11 @@ void setup() {
 	Serial.print("[SYSTEM] Generated device name: ");
 	Serial.println(deviceName);
 
+	// Construct the dynamic topic string
+	topic = "iot/purifier/" + deviceName + "/speed";
+	Serial.print("[SYSTEM] Using MQTT topic: ");
+	Serial.println(topic);
+
 	static int error_count = 0;
 
 	WiFi.hostname(deviceName.c_str());
@@ -113,7 +118,7 @@ void setup() {
 	Serial.print("[MQTT] Subscribing to topic: ");
 	Serial.println(topic);
 
-	mqttClient.subscribe(topic, QOS_2);
+	mqttClient.subscribe(topic.c_str(), QOS_2);
 
 	Serial.println("[MQTT] Waiting for messages.");
 }
@@ -136,7 +141,7 @@ void loop() {
 
 		Serial.print("[MQTT] Subscribing to topic: ");
 		Serial.println(topic);
-		mqttClient.subscribe(topic, QOS_2);
+		mqttClient.subscribe(topic.c_str(), QOS_2);
 	} else {
 		error_count = 0;
 		mqttClient.poll();
@@ -168,7 +173,11 @@ void onMqttMessage(int messageSize) {
 	Serial.println(message);
 
 	if (msgTopic != topic) {
-		Serial.println("[MQTT] Invalid topic, returning.");
+		Serial.print("[MQTT] Invalid topic '");
+		Serial.print(msgTopic);
+		Serial.print("', expected '");
+		Serial.print(topic);
+		Serial.println("'. Returning.");
 		return;
 	}