HC-05 Working solution

Projects Networking, Protocols, and Devices
1

After many trials and failures I have my HC-05 working on arduino.
I am using a MEGA board so serial2 is used but SoftwareSerial can also be used.
VCC-5 >> VCC
GND >> GND
TX >> RX
RX >> TX

char c = "";

void setup() {
  Serial.begin(9600);
  Serial.println("Enter AT command.");
  Serial2.begin(9600); // What ever you like

}
void loop() {
  if (Serial2.available()) {
    c = Serial2.read();
    Serial.print(c);
  }

  if (Serial.available()) {
    Serial2.write(Serial.read());
  }
}

In your serial monitor set speed to 9600 baud and both NL and CR.
Be sure your HC-05 is in AT mode (led flashing every few seconds)
Seems like every BT module is different during AT but this one worked for me

2

Not that different, and there is nothing to suggest it really is working for you - and quite a lot to suggest it isn't. For starters, if you really want to work in AT mode, Bluetooth needs to run at 38400 baud, and there is nothing "//what ever you like" about it. What you are doing rather suggests you are using an HC-06.

3

Nick, I stand corrected. I tried a different module and had to adjust Serial2.begin(38400); The new one I am using has 6 pins and a button. When first attached led was flashing fast. To put it into AT mode, I removed power, held the button down and reapplied VCC. At that point I saw a SLOW flash of LED (AT mode). Question.. AT+HELP on module #1 gave me a list of all AT commands. AT+HELP on module #2 returned ERROR:(0). A few other AT commands ie. AT+BAUD also return ERROR:(0).. AT+UART returns: 9600,0,0. thoughts?

4

Adequate evidence of it being an HC-05.....
I can only assume that different results are because modules #1, #2 are different versions. There are two levels of programmability and the commands returning an error may require 3.3v on pin34. The Martyn Currey website might have something on this.
I assume the 9600 response is in fact kosher as that is the setting for comms mode, and you haven't altered it.

5

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