HC-05 BT module is unable to connect with moble device

Other Hardware Sensors
6

  1. Check that you have connected the HC05 Module with UNO as per following diagram. The voltage divider circuit is needed as the RX-pin of HC05 is not 5V tolerant.

  2. Is the Red-LED of the BT Module continuously blinking?

  3. Have you installed a Bluetooth Terminal (BTT) in your android based smart phone?

  4. Check that the smart phone has detected your BT Module. If SN is asked, enter 0000 or 1234; they usually work.

  5. Connect your BTT with the BT module. Check that the RED-LED is now blinking once a while.

  6. Upload the following sketch in the flash of your UNO.

#include <SoftwareSerial.h>
SoftwareSerial BTserial(2, 3); // SRX | STX
// Connect the HC-05 TX to Arduino pin 2(as SRX).
// Connect the HC-05 RX to Arduino pin 3 (as STX) through a voltage divider.

void setup()
{
 Serial.begin(9600);
 BTserial.begin(9600);
}

void loop()
{
 if (BTserial.available())
 {
   byte x = BTserial.read();
   Serial.write(x);
 }

 if (Serial.available())
 {
   byte y = Serial.read();
   BTserial.write(y);
 }
}
  1. Check the functionality of the communication link:
    BTT <----> BT <----> UNO <----> Serial Monitor