Transmit/Receive data Nodemcu(V3) + Bluetooth Module HC-05

Question

I am trying to communicate with the HC-05 Bluetooth module for quite long time now, but with no success.

I am using the Nodemcu(V3) ESP8266 module.

I connect the HC-05 to Nodemcu in following sequence:

HC-05             Nodemcu
-----             -----------
RX       -->      Pin 1 (Tx)
TX       -->      Pin 3 (RX)
Vcc      -->      +3.3V
GND      -->      GND 

For starters, i want to check if my Nodemcu is communicating properly with my HC-05 module.

I have written the following code to read the response of AT commands:

#include <SoftwareSerial.h>
SoftwareSerial BTserial(3, 1); // RX | TX
char Bluetooth_Name = ' ';

void setup() 
{
    // Arduino IDE serial monitor
    Serial.begin(115200);

    // HC-05 default serial speed for AT mode is 38400
    BTserial.begin(38400);  

    // Wait for hardware to initialize
    delay(1000);

    // Print debug string
}

void loop()
{

   // Keep reading from HC-05 and send to Arduino Serial Monitor
   if (BTserial.available())
   {
      reading = BTserial.read();
      Serial.println(reading);
   }

   // Keep reading from Arduino Serial Monitor and send to HC-05
   if (Serial.available())
   {
      reading = Serial.read();
      BTserial.write(reading);
   }
}

However, i do not get response for any AT command at all. The serial monitor just shows blank.

Thanks in advance

EDIT:- I connected the "EN" pin on the HC-05 to Vcc. Now, the led on the HC-05 blinks slowly, which means that the HC-05 is configured in command mode. However, i am still not able to receive the response for any AT commands. I have also selected "Both NL & CR" in the serial monitor, configured the baud rate correctly and double-checked the hardware connections.

Everything seems to be correct except that i don't get response for the AT commands.

Please help!!!

Answer 1

I had the exact same problem and got it to work doing these changes:

I had to add this under my library include statements

#ifndef D5
#if defined(ESP8266)
#define D5 (14)
#define D6 (12)
#define D7 (13)
#define D8 (15)
#define TX (1)
#endif
#endif

and changed

SoftwareSerial BTserial(3, 1); // RX, TX

to

SoftwareSerial BTserial(D5,D6);

I used D5 and D6 on my esp8266 instead of D1 and D3 but shouldn't matter

Answer 2

I changed the line

SoftwareSerial BTserial(3, 1); // RX, TX

to

SoftwareSerial BTserial(D4, D3); // RX, TX

And got it to work!