I want to connect two HC-05 modules, one master and one slave. So to that I need to access 'AT Commands'.

Theoretically, I just needed to upload an empty code, and then connect the module to the arduino in command mode (I use a Nano) TX and RX pins and then go to the Serial Monitor at 38400 baudrate and sent the AT commands. In the past this worked for me, but now this ain't working anymore.

So I went for some code online and aparently AT commands started working. I configured master and slave, and binded the address of the slave to the master.

I connected the modules to an input voltage and I was expecting a connection between them but they are not pairing. On youtube videos they say to connect with two different arduinos, but doesnt make any sense to me because they should connect by themselves just for being ON.

I don't know what to do, I need these working for a project and I'm just wasting time searching on the internet, because nothing works for me. I just didnt tried using them with 2 arduinos with code on them, but I dont think thats the issue AND IF IT IS, please tell me what's the correlation.

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  • 1
    Are you sure about that the modules should connect automatically on startup? Honestly I wouldn't think that to be the case. Also: What exactly are you trying to do if you don't use 2 Arduinos with your two HC-05 modules?
    – chrisl
    Jun 22 at 11:08
  • @chrisl I saw man videos on youtube and after they configure the modules they just put them both in data mode and they pair by themselves, I dont really know why they put them alingside 2 arduinos. I'm using an arduino and an STM32, but as I said, they should connect by themselves
    – Bikke21
    Jun 22 at 21:09


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