ESP8266 Community Forum

Hello
I want to connect ESP to Arduino Nano, to send information via wifi fom arduino sensors. I want to use AT commands.

I've flashed the firmware - ESP8266_NONOS_SDK_V2.0.0_16_08_10. I have connected VCC and CH_PD to external 3.3V power supply, GND and GPIO15 -> GND, Tx -> Tx, Rx -> Rx with voltage divider to drop 5V -> ~3.3V.

I've plugged Arduino (with reset and ground connected) to computer and opened serial monitor. ESP gives me a message at baud 74880:

but it doesn't respond to any AT commands. Any help is appreciated

Can you "Talk" to the ESP directly (using a USB -> convertor) from within a program like PuTTY? Also: the ESP boots at 74880 Bd, but then switches over to 115200 Bd (or 9600 / 57600 with older firmware).

I'm using Arduino as a converter (reset and ground on arduino short-circuited, so it won't boot), I don't have any other converter. I've tried to talk using PuTTY, at 74880, 115200, 9600 and 57600 baud, nothing happens.

From your wiring arrangement, it looks like you have incorrectly tied Rx of the esp to Rx of the Arduino Nano and Tx of the esp to Tx of the Arduino Nano. I am also using an Arduino (Uno) to talk to an ESP8266-01. I have tied Tx on the Arduino thru the 5V to 3.3v resistor arrangement you have used to the Rx pin on the ESP8266. You can tie the Rx of the Arduino directly to Tx of the ESP8266 (without the dropping resistors) because the Tx sources the power for transmit to the Arduino and the Arduino will recognize the 3.3 volt high as a logic high. I have been using this communication configuration for two and a half years without any errors with data communication multiple times each day.
Note: You cannot talk to the Arduino via USB while you have the ESP8266 connected to the Tx and Rx lines of the Arduino. If you need both serial communication links active at the same time you will have to define two new pins on the Arduino as a software serial connection and use a software serial library to make the software serial port functional. Be sure to define baud rates on both serial ports and add code for reading/writing serial from one serial port to the other write/read on the software serial port.
If you want to see my wiring diagram you can look at the August 2017 Nuts and Volts magazine "Bi-Lingual Light and Appliance Control"