HC-05 AT+PSWD doesn't save

Projects Networking, Protocols, and Devices
1

Hi, I need to change and save HC-05 password. I can update the all "AT COMMAND" to HC-05 in arduino serial monitor. Every command is saved but except the AT+PSWD.
AT+PSWD=0000 command seems works and gives OK. But When I power off and on to arduino, password is changing to default password (1234) . Other result is ok (name, cmode, bind, class, role, uart e.g)
P.s. HC-05 version is = VERSION:4.0-20190815

2

@yavuzyildizhan , your tooic has been moved to a more suitable location on the forum. Installation and Troubleshooting is not for problems with (nor for advise on) your project.

3

What procedure do you use to putt the HC05 into AT mode?

5

groundFungus, blue led blink slowly at every 2 seconds and AT+ NAME, CMODE, ROLE, CLASS, BIND, PSWD is seems OK.
AT+PSWD=0000 and AT+PSWD="0000" gives OK and AT+PSWD? gives is AT+PSWD="0000"
But, when I restart the arduino, password goes to 1234 default pass. All other results are ok and saved.

hc-05
hc-051240×955 186 KB 

#include <SoftwareSerial.h>
SoftwareSerial Bluetooth(9,10);

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

void loop() 
{
  if(Bluetooth.available())
  {
    c=Bluetooth.read();
    Serial.write(c);
  }
  if(Serial.available())
  {
    c=Serial.read();
    Bluetooth.write(c);
  }
}
6

You did not answer this question.

Reading this write up by Martyn Currey there is a full and partial AT mode depending on pin 34.

If you were not in full mode, try that and see if the password change is saved.

7

Everything is fine now. Many thanks **@cattledog and @groundFungus **

1- I followed the procedures on this site
2- Before restart the Arduino, while in AT mode, I connected to bluetooth with AT+INQ and AT+LINK commands. Now AT+PSWD is saved and connecting to slave device with no problem.
3- Change to TX pin D10 to D9 and restart arduino. And take out the 3.3v from EN and Pin34 of course...

8

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.

10

I had the same problem on my HC-05 - VERSION:4.0-20190815

I could change the password using AT+PSWD=4321
and then view the new password AT+PSWD?
But after power cycling the module, the password was back at 1234

The solution I found was to

  1. connect up to arduino as illustrated above, using the voltage divider and 3.3V connected to EN
  2. change the password AT+PSWD=4321
  3. connect to the bluetooth module using a Windows laptop - connecting to the device using the new password saves it properly
    The module doesn't need to come out of AT mode to do this, just leave EN connected to 3.3V
  4. and now power cycle - the module still has the new password.