Hi , I have recently bought an HC-05 module for a small project. I am a beginner in Arduino but I had already used an HC-05 for a school project and everything was working fine.
My project implies for now to just put the module in slave mode.
I use an Elegoo uno R3.
The issue is when I put the HC-05 in AT mode (slow blinking led) I can send the "AT" command and get "OK" in return but for every other command I get nothing back and no modification are made ( I tried to change the name of the module with "AT+NAME=HC" but it remained "HC-05" on my phone).
And my second problem is that I use a baud rate of 9600 for the serial communication PC-Arduino and 38400 for Arduino-HC like it is chosen in all the documentation I found but when I do so I get a random response for my only AT command working "AT" : sometimes nothing happen , sometimes it respond with an OK.
But when I use 38400 for the PC-Arduino serial (unlike in the documentation) I get a response everytime.
I'm feeling lonely because I didn't find someone with the same problem so I hope you will have the answer !
appa27:
My project implies for now to just put the module in slave mode.
For starters, you don't need to "put it into slave mode" and never did. The HC-05 will work as a slave as it comes out of the box. Otherwise, what you are doing implies you know what you are doing, although it would SEEM that you have inadvertently changed PC<>Arduino comms to 38400 as well - which isn't actually a problem. In view of that, I think you are wasting your time getting a USB<>TTL board, and I don't think Martyn Currey will tell you to do that.
Since you are currently set up for AT mode, I suggest you try to check the version, as I believe you might have a fake. There are a lot of them about, and that is a place where you will not feel lonely....
Next, and actually more importantly, I suggest you try a simple "hello" with a phone terminal as slave - i.e. no AT stuff. That is all you need at the moment, and you may find it is just fine. Indeed, you may find you never actually need to use AT commands - which may be what the supplier was hoping.
You might find the following background notes useful.
if only because there is a little bit about fakes in there highlit in yellow. In fact, just about all I know about fakes. As I understand it, all fake HC-05s only show themselves as fakes when in AT mode, but the symptoms vary. There may be some updates on the Martyn Currey website.
Thank you for both of your answers, I could get my project to work without having to configurate the module. I won't try the USB TTL method since it work so if someone has the same problem as me he will have to try. I hope my module is a fake, that would give a clear answer even if we don't know how to bypass this difficulty.
Good. You might never need AT, and I believe your average fake is not entirely useless in AT mode anyway. What IS entirely useless is a TTL /USB adapter. There is no magic bullet to be found there, and you only need one if you don't have an Arduino.