Connecting esp-01 to a wifi client

i have connected my esp-01 via a cp2012 usb to ttl module in order to connect the esp01 to wifi. i used the esp8266 wifi client example sketch to do this...and once i'm connected to the wifi, the AT commands wont respond back on serail monitor of the arduino ide.
please assist on how i can test AT Commands after connectnig my esp-01 to a wifi client.


means you have successfully uploaded an *.ino-Sketch to your ESP8266-01-module
the sketch replaced the AT-firmware.

Your sketch is the new firmware. That is the reason why the ESP-8266-01-module does not respond anymore to AT-commands. The AT-firmware got overwritten by your sketch.

Don't worry you are on the right path. This AT-firmware is a big nightmare to use.
It will be much easier to use C++-code (like the WiFiClient-example) instead of the AT-firmware.

Anyway post in detail all the steps you have done. with what you have described too short as

From your question I can conclude that you are a newcomer. This means it is much more important to describe all the steps you have done because you might have a misconception of how it works and what means what.

It will save you minimum hours of time to get the problem solved by investing 15 minutes = 0,25 hours to write a very detailed description of what you have done so far.

especcially answer the questions:
did you use the Arduino-IDE ?
did you load the WiFiClient.ino-sketch?
did you enter flash-mode?
did you get a message "Leaving... Hard resetting via RTS pin..." at the end of the upload-process?

best regards Stefan

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Hi Stefan,thank you for responding back to my post. yes i am a newcomer and still trying to navigate around ,but to answer your question ,i'm gonna break down all the steps i've taken.

so the aim of my project is : to connect raspberry pi pico and/with esp-01 in order to send alarm notification to a website server or even blynk if it is possible.

the 1st step i took was to connect the esp01 to wifi,and in doing so i used the cp2102 module and esp-01(not esp01s) ,connected the hardware ...then on the software side i opened arduino IDE, and opened the example sketch: esp8266 wifi:wifi client ..then uploaded and got the Leaving... Hard resetting via RTS pin..." at the end of the upload-process.

i opened the serial monitor and it showed that wifi is connected.(here is the results from serial monitor)
08:29:55.622 -> Connecting to GAVINC 4025
08:29:56.135 -> ...........
08:30:01.871 -> WiFi connected
08:30:01.871 -> IP address:
08:30:01.871 ->
08:30:01.871 -> connecting to
08:30:02.151 -> sending data to server
08:30:02.478 -> receiving from remote server
08:30:02.478 -> "We have no more right to consume happiness without producing it than to
08:30:02.478 -> consume wealth without producing it." George Bernard Shaw (1856-1950)

so after that ...that's when i wanted to test the AT Commands and they failed on arduino ide,i moved to micropython Thonny and ran a program that side(hardware:connecting the esp01 and raspberry pi pico) and there was confirmation on the shell that wifi is connected.
here is the program i used on thonny:
from machine import UART, Pin
from time import sleep

uart1 = UART(1, baudrate=115200, tx=Pin(4), rx=Pin(5))

while True:
rxData = bytes()
while uart1.any() > 0:
rxData +=

if len(rxData):
    print(rxData.decode('utf.8'), end='')

and the results to that was:
WiFi connected
IP address:
connecting to
connection failed
connecting to
sending data to server
receiving from remote server
"A wonderful fact to reflect upon, that every human creature is constituted
to be that profound secret and mystery to every other."
Charles Dickens (1812-70)
closing connection
connecting to
sending data to server
receiving from remote server
In Heaven an angel is nobody in particular." George Bernard Shaw (1856-1950)
closing connection

please assist anywhere in order to achieve my main aim/objective of my project..
you respond will be highly appreciated.

side note: im using the esp01 and not the in that case i had to add resistors for pull up and add the flash and reset button in order for the espo1 to function properly

kind regard


With uploading the WiFiClient-code you have overwritten the AT-firmware.
You can imagine this process like taking a windows computer formatting the harddisc completely and then install a pure Linux on this computer.
There is not a single bit or byte left from the windows-operating system.

The same thing happened through uploading the WiFiClient-sketch.
At-firmware erased and


by your WiFiClient-sketch.

as I have written don't worry. You are on the right track. Forget all about at-commands.
Communicating with the WiFi becomes much more comfortable by using the C++-command-Set provided by the Arduino-IDE. The C++-command-Set


all AT-commands and

the C++Command-Set offers MUCH MORE COMFORT

than the AT-commands ever would

If you can afford to buy a ESP32-nodeMCU module for around 10 dollars

This ESP32-module


  • microcontroller
  • WiFi
  • Bluettooth
  • RTC (real time clock)

all in one module as shown above

The raspberry pi pico has

  • more IO-pins
  • better ADC
  • no WiFi
  • no bluetooth

Anyway If you would like to go on with the raspberry pi pico and the ESP-01 you can code your own data-exchange between the Raspico and the ESP-01.

best regards Stefan

1 Like

Thank you, this was really helpful

can you please assist on how i can flash back the AT commands firmware back to the esp-01?

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