HI all
so, the goal is i want the value of "waterlevel" is published to my MQTT Broker (installed on my main PC running Arch Linux), i've learned how to publish a topic to MQTT Server from my MCU from various resources onine, this time i used OpenAI's ChatGPT to generate a dummy value, and publish it to my MQTT Broker, and it works!, so nothing is wrong with my MQTT Broker. I applied it to my project code, it succesfully connected to the Wi-Fi, however my MQTT Broker (which is currently subscribed to the topic "topic") is not receiving any data...anybody knows what's wrong? 
Here is my Project code :
//Declaration of Library :
#include <ESP8266WiFi.h> //Wi-Fi Networking Library
#include <PubSubClient.h> //MQTT Publish & Subscribe Client
// Declaration of I/O :
//Sensors :
const int tank_sensor = A0;
const int soil_sensor = D0;
//Actuators :
const int buzzerPin = D1;
const int PumpPin = D3;
const char* ssid = "Rizki Rizka"; //Wi-Fi SSID
const char* password = "8520032522013"; //Wi-Fi Password
const char* mqtt_server = "192.168.100.79"; //IP Address of MQTT Broker
// Pure value from reading the sensors:
int waterlevel;
int soillevel;
// Status stored from reading the sensor value :
boolean LowWater = false;
boolean NeedWatering = false;
// MQTT & Wi-Fi Client name :
WiFiClient espClient;
PubSubClient client(espClient);
void connectwifi(){
WiFi.begin(ssid, password); //connect to wifi network
while (WiFi.status() != WL_CONNECTED) { //wait until ESP8266 connects to wifi network
delay(1000);
Serial.println("Connecting to WiFi...");
}
Serial.print("Connected to WiFi: ");
Serial.println(WiFi.SSID()); //print connected wifi network name
Serial.print("IP address: ");
Serial.println(WiFi.localIP()); //print IP address
if (WiFi.status() == WL_CONNECT_FAILED){
Serial.println("Connection Failed");
}else{
}
}
void setup() {
// Start a Serial Communication :
Serial.begin(115200);
// Declare Buzzer and Pump (Relay) as output :
pinMode(buzzerPin, OUTPUT);
pinMode(PumpPin, OUTPUT);
// Change the state value to HIGH because we use a Low Level Trigger Buzzer & Relay :
digitalWrite(buzzerPin, HIGH);
digitalWrite(PumpPin, HIGH);
//Call the Netowrk Function to connect to Wi-Fi :
connectwifi();
// Set the port of the MQTT Server :
client.setServer(mqtt_server, 1883);
}
void watchsensors() {
waterlevel = analogRead(tank_sensor);
soillevel = digitalRead(soil_sensor);
if (waterlevel <300){
LowWater = true;
}else{
LowWater = false;
}
}
void lowWaterlvl(){
static unsigned long previousMillis = 0; // Store the previous time
unsigned long currentMillis = millis(); // Get the current time
static int state = 0; // Store the current state
static int beepDuration = 150; // Store the beep duration
if (currentMillis - previousMillis >= beepDuration) { // If the beep duration has passed
previousMillis = currentMillis; // Update the previous time
switch (state) {
case 0:
digitalWrite(buzzerPin, LOW); // Turn the buzzer on
state = 1; // Go to the next state
break;
case 1:
digitalWrite(buzzerPin, HIGH); // Turn the buzzer off
state = 2; // Go to the next state
break;
case 2:
digitalWrite(buzzerPin, LOW); // Turn the buzzer on
state = 3; // Go to the next state
break;
case 3:
digitalWrite(buzzerPin, HIGH); // Turn the buzzer off
state = 4; // Go to the next state
break;
case 4:
// Do nothing
state = 5; // Go to the next state
break;
case 5:
state = 0; // Reset to the first state
break;
}
}
}
void printInfo(){
// Print The Water Level :
Serial.print("Water Level : ");
Serial.println(waterlevel);
delay(200);
// Print the Soil Level :
Serial.print("The soil is currently : ");
Serial.println("nyc");
}
void watertheplant(){
Serial.println("Not yet coded");
digitalWrite(PumpPin, LOW);
delay(1000);
digitalWrite(PumpPin, HIGH);
delay(1000);
}
void loop() {
watchsensors();
printInfo();
//Actions :
// Trigger Buzzer if water tank level is low :
if (LowWater == true){
lowWaterlvl();
}else{
digitalWrite(buzzerPin, HIGH);
// Trigger Pump if Soil is Dry :
//mqttt:
client.loop();
static unsigned long previousMillis = 0;
unsigned long currentMillis = millis();
if (currentMillis - previousMillis >= 1000) {
previousMillis = currentMillis;
client.publish("topic", String(waterlevel).c_str());
}
}
}
Please note that is wasn't done yet, so there are some function not yet realy used
And below is the code from ChatGPT as my reference :
#include <ESP8266WiFi.h>
#include <PubSubClient.h>
const char* ssid = "Rizki Rizka"; //replace with your wifi network name
const char* password = "8520032522013"; //replace with your wifi network password
const char* mqtt_server = "192.168.100.79"; //replace with your mqtt server IP or hostname
WiFiClient espClient;
PubSubClient client(espClient);
int waterlevel = 0;
void setup() {
Serial.begin(115200);
WiFi.begin(ssid, password); //connect to wifi network
while (WiFi.status() != WL_CONNECTED) {
delay(1000);
Serial.println("Connecting to WiFi...");
}
Serial.println("Connected to WiFi");
client.setServer(mqtt_server, 1883);
reconnect();
}
void loop() {
client.loop();
static unsigned long previousMillis = 0;
unsigned long currentMillis = millis();
if (currentMillis - previousMillis >= 1000) {
previousMillis = currentMillis;
// read the value of waterlevel from your sensor here
client.publish("topic", String(waterlevel).c_str()); //publish the waterlevel value
}
}
void reconnect() {
while (!client.connected()) {
if (client.connect("ESP8266Client")) {
Serial.println("Connected to MQTT server");
} else {
delay(1000);
}
}
}
This one works, however when i applied it to my project(the first code) it does not seems to publish anything....anyone knows what's wrong 
