Has anyone tried the GT-38 wireless module?

Thread Starter

srFelipes

Joined Jul 3, 2020
7
Hi, I recently bought some GT-38 modules, they are supposedly an HC-12 replacement and work in the same fashion (https://www.electrodragon.com/w/GT-38). I tried to change the baudrate with no luck and I can't get them to do anything. I tried sending the command AT while the SET pin is tied to ground but I get no response. The only thing that gets an answer from the module is when I send the command AT+RB and its ERROR. Has somebody used this module or know what causes this?

Thanks in advance!
 

Thread Starter

srFelipes

Joined Jul 3, 2020
7
Hi Eric, thanks for your answer. Yes I saw it and tried that, with an arduino and an usb to serial TTL as shown in the site and that's how i got the ERROR message. I tried with 9600 baudrate, I'll try 1200 and see if it works, Thanks!

EDIT: Tried the 1200 baudrate and it does not solve the problem, the only bauradte in which y get the answer is 9600 and its ERROR :(
 

Peterlang20

Joined Jun 15, 2021
1
Hi, I recently bought some GT-38 modules, they are supposedly an HC-12 replacement and work in the same fashion (https://www.electrodragon.com/w/GT-38). I tried to change the baudrate with no luck and I can't get them to do anything. I tried sending the command AT while the SET pin is tied to ground but I get no response. The only thing that gets an answer from the module is when I send the command AT+RB and its ERROR. Has somebody used this module or know what causes this?

Thanks in advance!
Just be careful where you buy the modules from Much like the HC-12 there are clones about which do not have the current firmware installed or even hacked firmware. Like the HC-12 , clones do not have the original manufactures Tran mark symbol screen printed on the back. Photos attached show clone in first photo and Original in second
 

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calinux

Joined Feb 17, 2022
2
Hi,
I'm facing exactly the same problem with the new GT-38 modules. I also bought them as a replacement for my existing boards which are using HC-12. I have tried now 2 modules and both have exactly the same issue - they will answer with "ERROR" to any of my AT commands.
I have tried 2 different USB to UART adaptors, I have tried out from Arduino but same problem.
The communication between 2 modules (using their default settings with BAUD 9600) seems to work.
Since the received message for my AT command can be decoded as "ERROR" string, is definitely not a BAUD rate issue.
 

calinux

Joined Feb 17, 2022
2
Hi,
I'm facing exactly the same problem with the new GT-38 modules. I also bought them as a replacement for my existing boards which are using HC-12. I have tried now 2 modules and both have exactly the same issue - they will answer with "ERROR" to any of my AT commands.
I have tried 2 different USB to UART adaptors, I have tried out from Arduino but same problem.
The communication between 2 modules (using their default settings with BAUD 9600) seems to work.
Since the received message for my AT command can be decoded as "ERROR" string, is definitely not a BAUD rate issue.
I have found the issue. After a lot of testing, it looked like some the module was somehow partially parsed "AT+R*" commands because only for such commands it was returning "ERROR" but for random text it did not return anything. So I have started to add "\0" (0 byte which means string end) to the AT command, tried with \n at the end of command then tried with \r\n (carriage return +new line) at the end of AT message and BINGO. Got the response. So for all who are lucky to reach this forum, you must send the AT command like "AT+RX\r\n" and you will get the response.
 
I have found the issue. After a lot of testing, it looked like some the module was somehow partially parsed "AT+R*" commands because only for such commands it was returning "ERROR" but for random text it did not return anything. So I have started to add "\0" (0 byte which means string end) to the AT command, tried with \n at the end of command then tried with \r\n (carriage return +new line) at the end of AT message and BINGO. Got the response. So for all who are lucky to reach this forum, you must send the AT command like "AT+RX\r\n" and you will get the response.
You are correct. Also if testing the GT-38 modules with Arduino, in the 'Serial Monitor', set to "carriage return". Then it will recognize your AT commands.
 
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