problem: I can't get in AT command mode for HC-05

hi, i have a problem in accessing AT command mode for HC-05 Bluetooth
recently i found a code for to perform this task but when i send any thing there is no response
however the Bluetooth led blinking very slow 2 sec on 2 sec off


AUTHOR: Hazim Bitar (techbitar)
DATE: Aug 29, 2013
LICENSE: Public domain (use at your own risk)
CONTACT: techbitar at gmail dot com (


#include <SoftwareSerial.h>

SoftwareSerial BTSerial(10, 11); // RX | TX

void setup() 
  pinMode(9, OUTPUT);  // this pin will pull the HC-05 pin 34 (key pin) HIGH to switch module to AT mode
  digitalWrite(9, HIGH); 
  Serial.println("Enter AT commands:");
  BTSerial.begin(38400);  // HC-05 default speed in AT command more

void loop()

  // Keep reading from HC-05 and send to Arduino Serial Monitor
  if (BTSerial.available())

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

any help will be appreciated
thank you :slight_smile:

I used

You can try press and hold the button switch on the BT module before powering ON BT and the release the button... (Sorry for my English) :slight_smile:

Thank you very much it was very useful