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1

i have arduino and bluetooth shield , i want to enter to AT command mode

my connection
arduino > bluetooth shield
rx > tx
tx > rx
pinMode 9 > pinMode 9
5v > 5v
gnd > gnd

and i uploaded the code, why serial monitor replying me that symbols T.T i cant enter AT mode ,its been 3months i think, i cant still go to AT command mode :o

#include <SoftwareSerial.h>

SoftwareSerial BTSerial(0, 1); // 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.begin(9600);
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())
Serial.write(BTSerial.read());

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

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2

Is your serial monitor set up for 9600 baud rate? Usually there is a mismatch between baud rates if the monitor is spitting out gibberish.

3

You set the software serial to the Hardware serial pins...

4

Gippopotam:
You set the software serial to the Hardware serial pins...

You also cross-posted!

5

PaulS:
You also cross-posted!

explain it

6

I think PaulS was referring to the OP, this was also in Programming earlier.

7

PaulS:
You also cross-posted!

Gippopotam:
You set the software serial to the Hardware serial pins...

my serial monitor was set up to 9600 baud rate
can you pls explain what do you mean by i set the software serial to the hardware serial pins??

8

rmtc:
my serial monitor was set up to 9600 baud rate
can you pls explain what do you mean by i set the software serial to the hardware serial pins??

SoftwareSerial BTSerial(0, 1); // RX | TX
0,1 - this is Hardware serial

9

Gippopotam:

SoftwareSerial BTSerial(0, 1); // RX | TX
0,1 - this is Hardware serial

but the only rx , tx is 0 , 1 where should i connect rx tx cause on my arduino its only 0,1 :frowning:

10

but the only rx , tx is 0 , 1 where should i connect rx tx cause on my arduino its only 0,1

Those pins are used by the HardwareSerial class. Serial is an instance of that class. If you are going to use those pins, you are NOT going to use SoftwareSerial.

SoftwareSerial CAN be used on ANY other two pins, as long as those pins support pin change interrupts (on a Uno, all pins do). You must make sure that the device you want to be reading from/writing to is connected to the pins you are reading from/writing to.

11

Try connecting the Arduino reset pin to ground. Then, open the Serial Monitor and enter "AT+BAUD". If you get gibberish, change the baud rate.