ESP8285 Stuck on Wi-Fi Connect

Projects Networking, Protocols, and Devices
1

Hi everyone,

I'm working on a project using an Arduino Uno to control an ESP8285 module (running AT firmware) for MQTT.

I am completely stuck on the very first step: The ESP8285 will not connect to my Wi-Fi network.

The module is silent and times out after sending the connection command.

My Setup & Problem

• Module: ESP8285 with AT Firmware (controlled by Arduino Uno). Fails to connect.

• Command: AT+CWJAP="SIDD","Pass"

• Result: Returns Timeout (no OK or FAIL response).

• Communication: Hardware Serial (Pins 0/1) set to 9600 baud. Confirmed stable and reliable.

• Power: Dedicated external 3.3V supply used. Confirmed stable (ruled out the main cause).

doitwifi
doitwifi361×361 26.1 KB
`

// --- Global Configuration ---
// Using Hardware Serial (Pins 0 and 1) for ESP8285 communication (Most reliable)
#define ESP_SERIAL Serial 
#define DEBUG_SERIAL Serial 
const int LED_PIN = LED_BUILTIN; // Pin 13 on Arduino Uno for visual status

// Global flag to track connection status
bool isConnected = false; 

// Network Credentials (Check these CAREFULLY for typos and case-sensitivity)
const char* WIFI_SSID = "Mena";
const char* WIFI_PASSWORD = "12341234xwz";

// MQTT Broker Details (Your Mac/Mosquitto)
const char* MQTT_SERVER_IP = "192.168.1.5";
const int MQTT_PORT = 1883;
const char* MQTT_TOPIC = "esp/sensor/data";
const char* MQTT_CLIENT_ID = "ESP_Client_1";
const char* MQTT_USER_CFG_CMD = "AT+MQTTUSERCFG=0,1,\"ESP_Client_1\",\"\",\"\",0,0,\"\"";

// Sensor Data (Example values - replace with actual sensor reading logic)
float temperature = 25.10;
float humidity = 43.20;

// --- Function Prototypes ---
void sendATCommand(const char* command, int waitTime, const char* expectedResponse);
bool connectWiFi();
void configureAndConnectMQTT();
void publishSensorData();

// --- Setup ---
void setup() {
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW); // LED off initially

  // CRITICAL CHANGE: Using 9600 baud for stability with Arduino Uno and ESP8285
  DEBUG_SERIAL.begin(9600); 
  ESP_SERIAL.begin(9600);   
  DEBUG_SERIAL.println("--- Starting ESP8285 Setup for MQTT (Baud: 9600) ---");
  
  // Flash LED twice to confirm setup started
  digitalWrite(LED_PIN, HIGH); delay(100); digitalWrite(LED_PIN, LOW); delay(100);
  digitalWrite(LED_PIN, HIGH); delay(100); digitalWrite(LED_PIN, LOW); delay(500);

  // 1. Permanently set ESP8285 firmware to 9600 baud for reliable communication
  DEBUG_SERIAL.println("Setting ESP Baud Rate to 9600...");
  sendATCommand("AT+UART_CUR=9600,8,1,0,0", 500, "OK"); 

  // 2. Initial AT commands
  sendATCommand("AT", 200, "OK");
  sendATCommand("AT+RST", 2000, "ready");
  sendATCommand("AT+CWMODE=1", 200, "OK"); // Set to station mode

  // Attempt the Wi-Fi connection and set the global flag
  isConnected = connectWiFi();

  if (isConnected) {
    DEBUG_SERIAL.println("--- Wi-Fi Connected. Proceeding to MQTT ---");
    digitalWrite(LED_PIN, HIGH); // SUCCESS: LED ON SOLID
    configureAndConnectMQTT(); 
  } else {
    DEBUG_SERIAL.println("!!! FAILED TO CONNECT WI-FI. LED blinking error. !!!");
    // FAILURE: LED blinks fast, handled in loop()
  }
}

// --- Main Loop ---
void loop() {
  if (isConnected) {
    // If connected, LED is solid. Send data every 10 seconds.
    publishSensorData();
    digitalWrite(LED_PIN, HIGH); // Keep LED on
    delay(10000); 
    
  } else {
    // If not connected, blink the LED rapidly to show error state.
    digitalWrite(LED_PIN, HIGH); 
    delay(200);
    digitalWrite(LED_PIN, LOW);
    delay(200);

    // After blinking for a while, retry connection every 10 seconds
    static unsigned long lastRetry = 0;
    if (millis() - lastRetry > 10000) {
        DEBUG_SERIAL.println("!!! Connection failed in setup. Retrying Wi-Fi... !!!");
        isConnected = connectWiFi();
        if (isConnected) {
            digitalWrite(LED_PIN, HIGH); // SUCCESS: LED ON SOLID
            configureAndConnectMQTT();
        }
        lastRetry = millis();
    }
  }
}

// --- Core Communication Functions ---

bool connectWiFi() {
  char command[64];
  sprintf(command, "AT+CWJAP=\"%s\",\"%s\"", WIFI_SSID, WIFI_PASSWORD); 
  
  DEBUG_SERIAL.print(">>> Command: ");
  DEBUG_SERIAL.println(command);
  ESP_SERIAL.println(command);
  
  // Set a 30-second timeout for robust connection 
  long startTime = millis();
  String response = "";
  
  while (millis() - startTime < 30000) { 
    if (ESP_SERIAL.available()) {
      char c = ESP_SERIAL.read();
      DEBUG_SERIAL.write(c);
      response += c;
      
      // Look for the success messages
      if (response.indexOf("WIFI GOT IP") >= 0) { // More specific success check
        return true;
      }
      // Look for the specific failure message
      if (response.indexOf("FAIL") >= 0 || response.indexOf("ERROR") >= 0) {
        return false;
      }
    }
  }
  DEBUG_SERIAL.println("\n[Wi-Fi Connection Timeout]");
  return false;
}

void configureAndConnectMQTT() {
  DEBUG_SERIAL.println("--- Configuring MQTT Client ---");

  // 1. Configure the Client (ID, No Auth)
  sendATCommand(MQTT_USER_CFG_CMD, 500, "OK"); 

  // 2. Connect to the Broker
  char connect_command[64];
  sprintf(connect_command, "AT+MQTTCONN=0,\"%s\",%d,0", MQTT_SERVER_IP, MQTT_PORT);
  DEBUG_SERIAL.print(">>> Command: ");
  DEBUG_SERIAL.println(connect_command);
  
  // Wait for +MQTTCONNECTED and OK
  sendATCommand(connect_command, 5000, "+MQTTCONNECTED"); 
  sendATCommand("", 500, "OK"); // Check for final OK
}

void publishSensorData() {
  char payload[32];
  sprintf(payload, "T:%.2f,H:%.2f", temperature, humidity);
  
  char publish_command[128];
  sprintf(publish_command, "AT+MQTTPUB=0,\"%s\",\"%s\",0,0", MQTT_TOPIC, payload);
  
  DEBUG_SERIAL.print("Attempting to send: ");
  DEBUG_SERIAL.println(payload);
  
  DEBUG_SERIAL.print(">>> Command: ");
  DEBUG_SERIAL.println(publish_command);
  sendATCommand(publish_command, 1000, "+MQTTPUB:OK");

  DEBUG_SERIAL.println("--- Data Send Attempt Complete ---");
}

void sendATCommand(const char* command, int waitTime, const char* expectedResponse) {
  if (strlen(command) > 0) {
      ESP_SERIAL.println(command);
  }
  
  long startTime = millis();
  String response = "";
  
  while (millis() - startTime < waitTime) {
    if (ESP_SERIAL.available()) {
      char c = ESP_SERIAL.read();
      DEBUG_SERIAL.write(c); 
      response += c;
    }
    
    if (expectedResponse != NULL && response.indexOf(expectedResponse) >= 0) {
      break;
    }
    if (response.indexOf("ERROR") >= 0 || response.indexOf("FAIL") >= 0) {
      DEBUG_SERIAL.println("\n[AT ERROR Detected]");
      break; 
    }
  }
}
`
2

Just checking that it responds correctly to most other commands ?

Using an UNO to control an ESP is a bit like buying a Ford Mustang and putting a Horse in front to pull it (rather than putting the horse in a trailer and let the Mustang do the pulling) but it can be done.

#define ESP_SERIAL Serial 
#define DEBUG_SERIAL Serial

You should not use the same port for both, that will result in double messages to the ESP.

void sendATCommand(const char* command, int waitTime, const char* expectedResponse) {
  if (strlen(command) > 0) {
      ESP_SERIAL.println(command);
  }

And you should always explicitly add the 2 terminating characters "\r\n" after every AT-command or the ESP won't recognize the command at all.
So rather something like

ESP_SERIAL.print(command);
ESP_SERIAL.print("\r\n");
3

Or
ESPSERIAL.println(command);
?

4

Nope ! Println() does not send both NL & CR

5

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image1480×675 61.3 KB

6

I stand corrected. Are you sure the order in which they are sent is correct ?
I thought it only sent a NEWLINE (and no CR)

7 
void setup() 
{
  Serial.begin(19200);
}

void loop() 
{
  Serial.println("Hi Deva_R");
  delay(2000);
}

image
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