AT commends doesn't work hc-05

Projects General Guidance
1

I connected my Hc-05 to my arduino uno but i dont get respond to any of the AT commends.
I also made sure im in the programing mode so i held the button on the hc-05 when powering on and it blinks at interval of 2 seconds.
Also in serial monitor im 9600 baud rate and using Both NL&CL.

I conncted like that:
vcc-5v
gnd-gnd
txd-d2
rxd-d3
The code:

#include <SoftwareSerial.h>
SoftwareSerial Bluetooth(2,3);

char c=' ';
void setup() 
{
  Serial.begin(9600);
  Serial.println("ready");
  Bluetooth.begin(38400);
}

void loop() 
{
  if(Bluetooth.available())
  {
    c=Bluetooth.read();
    Serial.println(c);
  }
  if(Serial.available())
  {
    c=Serial.read();
    Bluetooth.write(c);
  }
}

Also I know that my hc-05 works because I use it for other things but I want to change the name and mostly access to the AT commends.
Thanks.

2

(deleted) your say your MCU works in other sketches

3

? I dont understand

4

@dzh121 Installation and Troubleshooting is for Problems with the Arduino IDE itself NOT your project. It says so in the description of the section.

Therefore I have moved your post here. Please be more careful where you post in future.

You may want to read this before you proceed:-
how to get the best out of this forum

5

You are totally right didn't notice on what category it was thanks you for your time

6

Checking the manual/datasheet would likely tell what the reason is.

A small schematics of how the setup is powered could be of help.

7

Look at this page. It helped me to get my HC05 modules into AT mode.
http://www.martyncurrey.com/arduino-with-hc-05-bluetooth-module-at-mode/

ON my modules, connecting the EN pin to 3.3V and then powering with 5V put them into AT mode and I could change any parameter that I desired. Make sure you use 3.3V to the EN pin, NOT 5V.

8

Did try it, and it worked (last time i tried with the EN it didnt now it did work) Thanks i will notfiy you if there is any problem.

9

If you still have trouble:

Post a schematic of your connections. Hand drawn, photographed and posted is fine. Include all pin names/numbers, components, their part numbers and/or values and power supplies.

Post photos of your wiring. Sometimes we see things that you have missed.

When you press the button an then power the module or connect 3.3V to the EN pin and power the module what pattern does the LED on the module flash?

10

You can look above your message it. does kinda work(I do get a reply now), when i try to do AT+NAME=TEST- I get ERROR:(0)

11

There are some bogus modules out there. I have seen this lately where someone can't get a module to work so they order new ones from a more reputable vendor then those work fine.

What do you get with "AT+VERSION?"?

12

I get for every commend ERROR:(0)

13

See post #9, please.

14

yeah im working on it just a minute

15

My fritzing app is not working. I will draw the schematic

16

WhatsApp Image 2022-08-07 at 12.42.06 AM
WhatsApp Image 2022-08-07 at 12.42.06 AM900×1600 48.5 KB

If the schem is not good. You can wait couple of minute while i fix my frtizing

17

Your drawing shows what is needed to see. I always use a voltage divider between the Uno TX and HC05 RX as the HC05 inputs are not supposed to be 5V tolerant. I don't know if that will make a difference since I have never done without. Have you tried with the divider?

image
image800×546 92.3 KB

18

I see you conncted 3.3v to the one of the pin above, why is that is that like the en or diffrent? do i need to do it?
Also i dont have 2k ressistor but i do have 1.8k wil it be fine with the 1.8?

19

I used that diagram to show the voltage divider.

That diagram is from the Martyn Currie tutorial that I linked earlier. In the tutorial he explains why that wire instead of the EN pin. My modules (8 so far) all work using 3.3V to the EN pin so I have not had to resort to soldering that extra wire.

There seem to be different levels of access in the AT mode depending on the modules that you have and the method to put the module into AT mode. A thorough examination of the tutorial may help you.

20

It realy weird that even the most basic at commend doesnt work(AT). I realy dont kno what to do anymore to be honest