AT-09 bluetooth module no response

I’m running dry here guys.

I have a AT-09 bluetooth module plus Arduino uno and I’m trying to take the famous OK answer. Nothing.
The closest i came was when I did AT-09 RX->RX(pin 0) ARDUINO and AT-09 TX-> TX(pin 1) Arduino,where i get for once an OK and then unrecognized chars.
I tried this sketch:

#include <SoftwareSerial.h>

//set ports
// state pin 
#define rx 3 // => HC05: rx my latest implementation was with those pins
#define tx 2 // => HC05: tx
// GND pin
// 5V pin
#define cmd 6 //EN pin

SoftwareSerial BTserial(rx, tx); // RX | TX of Arduino

char reading = ' ';

// BTconnected will = false when not connected and true when connected
boolean BTconnected = false;

void setup()
  // start serial communication with the serial monitor on the host computer
  // set input through EN pin
  pinMode(cmd, OUTPUT);
  digitalWrite(cmd, HIGH);

  //Serial turns on in 1 second. Be patient and wait.

  // wait until the HC-05 has made a connection
  while (!BTconnected)
    if (digitalRead(cmd) == HIGH) { BTconnected = true; };

  Serial.println("HC-05 is now connected");

  // Start serial communication with the bluetooth module
  // HC-05 default serial speed: 9600 or 38400
  Serial.println("Enter AT commands:");
  BTserial.begin(38400);  // HC-05 default speed in AT command mode

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

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

No luck so far,tried different baud rates and nothing.
The red led in AT-09 flashes as it should (1/ 2sec) and i can see it in my phone but nothing happens.
Any help?

Did you connect Rx to Rx or Rx to Tx?

The closest i came was when I did AT-09 RX->RX(pin 0) ARDUINO and AT-09 TX-> TX(pin 1) Arduino

No you didn’t, you were just kidding yourself. I have never heard of an AT-09 but, assuming that it will work like an HC-05 as you imply you may find



  1. If you want to send AT commands, this has nothing to do with the phone - just Arduino <> Bluetooth.

  2. You cannot talk to Android while in AT mode.

  3. While 38400 is the rate required for AT mode, if you want to talk to Android using that rate, you have to specifically configure Bluetooth accordingly, which I bet you have not done.

  4. You don’t need to configure anything in order to talk to Android.

I now understand that your AT-09 is a BLE device and NOT like an HC-05. Therefore, using code and procedures appropriate to HC-05 is not such a good idea. So in the above notes.

  1. The defult baud for both AT mode AND comms is 9600

BLE devices are in AT mode by default, any code to do with the EN pin is redundant, as indeed is the pin.

You might get some more information on the Martyn Currey website, referring to HM-10.