Hi, i have a question about Arduino Nano and bluetooth module HC-05. I have an Arduino nano, HC-05 and i cant get response from serial monitor. I have connection (screenshot) + code (screenshot) and when i turn the power and upload code from Arduino IDE and hold button on HC-05 to enter AT mode i get slowly blinking HC-05. But when i type "AT" into serial monitor it only blinks once RX diode on Arduino. So im begging for some tips. Thanks for helping!!! [image] [code]

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Hello @tuhacek I think you will find this relevant to the problem you are having: [image] Common ground and why you need one General Electronics A common mistake for people new to electronics is to have 2 circuits fed from different power supplies with signals passing between the circuits, but with the grounds not connected. This leads to questions asking why the project doesn't work. You don't have to spend long reading the questions on this forum to see this is asked often. Here I attempt to explain the problem and why it matters to connect the grounds. Note that in all of the schematics that follow I have used a battery as a power sup…

38400 is very optimistic for softwareserial on a small low-speed micro. Try 9600 bps Also, depending on what you’re trying to do, Serial.primt might work better.

Ignore the above, 38400 is required for AT mode with HC-05 I believe you have wired Rx/Rx. You need Tx to Rx Nano is capable of powering Bluetooth, why make things more difficult? It is good practice to use a 1k/2k voltage divider in Arduino Tx line. I'm sure the code is wrong. Check the Martyn Currey website for proper code and wiring.

[image] Nick_Pyner: It is good practice to use a 1k/2k voltage divider in Arduino Tx line. HC-05 module RX pin might use 3v3 logic level.

I think your wiring is incorrect. The TX pin of Arduino need to be connected to RX pin of HC-05, and vice versa. You can test the wiring by running simple code in Arduino HC-05 tutorial

Arduino nano+HC-05

Projects Programming

PerryBebbington March 7, 2024, 9:28pm 3

Hello @tuhacek

I think you will find this relevant to the problem you are having:

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