Can't connect hc-05 module

Projects Programming
1

This is my first time using hc-05 module and i tried a lot of diffrent codes, I found on the internet, but still can't solve this. I'm using Arduino Uno.
My connections are:
VCC -> 3.3V
GND -> GND
TXD -> RX(0)
RXD -> TX(1)

Module blinks properly (2 sec interval), now i'm using this code:

#include <SoftwareSerial.h>

SoftwareSerial mySerial(1,0); // RX, TX

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

void loop()
{
  while (mySerial.available())
    Serial.write(mySerial.read());

  while(Serial.available())
     mySerial.write(Serial.read());
}

I selected both NL & CR, tried to change baud, but nothing happened. After sending 'AT', 'AT+NAME?' it returns nothing.
Thank you in advance for your help.

2

Welcome to the forum

You started a topic in the Uncategorised category of the forum when its description explicitly tells you not to

Your topic has been moved to a relevant category. Please be careful in future when deciding where to start new topics

3

Will your module run on 3.3V?
Do you have a voltage divider between the Uno TX and HC-05 RX?
Don't use software serial on pins 0,1. Use 2 and 3

4 
SoftwareSerial mySerial(1,0); // RX, TX

You cannot use SoftwareSerial on pins 0 and 1 because they are used by the hardware Serial interface

Use two other pins of your choice

5

Thank you for your answer. I changed ports and switched 3.3V to 5V. But now it is returning strange symbols.

Screenshot (40)
Screenshot (40)2558×560 24.7 KB

6

Set the monitor baud rate to 9600

8

did you send a command and wait for a response?

9

I don't know what waiting time is normal. I uploaded sketch, opened serial monitor, sent 'AT'. I'm waiting 7 minutes now, but there is still nothing.

10

What have you got the Line Ending set to in the Serial monitor ?

Please post your sketch as it is now and describe which pin of the Uno is connected to which pin of the HC-05

11

You need to connect the enable/key pin to 5V to go into AT mode.
So connect the enable/key pin to say pin 4, set pin 4 mode to output and digitalWrite pin 4 HIGH.
Do you have the voltage divider on the TX pin?

12

My sketch is now:

#include <SoftwareSerial.h>

SoftwareSerial mySerial(6,5); // RX, TX

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

void loop()
{
  while (mySerial.available())
    Serial.write(mySerial.read());

  while(Serial.available())
     mySerial.write(Serial.read());
}

Connections:
VCC -> 5V
GND -> GND
TXD -> 5
RXD -> 6
Monitor: both NL & CR, baud 9600

13

Where should I add digitalWrite?
Yes, I have voltage divider.

14

Voltage divider:

image
image882×488 5.28 KB

15

You have TX/RX backwards

TXD -> 6
RXD ->5

16

Try this code

#include <SoftwareSerial.h>

SoftwareSerial mySerial(6, 5); // RX, TX

void setup()
{
  Serial.begin(9600); // Set serial monitor to 9600
  //mySerial.begin(9600); // For Data Mode
  mySerial.begin(34800); // For AT mode

  pinMode (7, OUTPUT); // Connect to HC-05 Enable/KEY pin
  // digitalWrite (7, LOW); // Now in Data mode
  digitalWrite (7, HIGH); // Now in AT mode
}

void loop()
{
  mySerial.print ("AT"); // Send AT
  delay (1);

  if (mySerial.available() > 0) {
    // read the incoming char:
    char incomingByte = mySerial.read();

    // print what was received (should be "OK")
    Serial.print(incomingByte);
  }
}
17

You can take a look at Controlling led using HC-05 bluetooth module

18

Well, nothing changed. I will try use USB-UART TLL. Maybe this will help. Thank you all.

19

I'm trying to connect my HC-05. I tried to use Arduino Uno, but nothing worked. I decided to use USB-UART TTL with CoolTerm. My module is blinking every 2 sec (in AT mode), I tried different braudrates, but after sending 'AT' module retured nothing.
I really don't know what to do.
My connections are:
GND->GND
5V+->VCC
RXD->TXD
TXD->RXD
Thank you for your help.

22

Threads merged.

23

I found a problem.

IMG_1505
IMG_1505960×720 190 KB

My new module is under. You can see some differences. I solved it after adding a wire.
IMG_1504
IMG_15041920×1440 395 KB

Well… Now it is working.