Send Email With ESP8266 and Arduino UNO





Introduction: Send Email With ESP8266 and Arduino UNO

How to get Adafruits "send_email_smtp.ino" to send email with ESP8266 and Arduino UNO.

And eliminating the problem with "no response from module" many have.

The module works on 3.3v logic according to documentation, but I had no issue with 5v rx and tx of arduino, play it at your own risk !!

Step 1: Firmware on the ESP8266

  • To get it working, must the firmware on the ESP8266 be version: ! (old firmware!)
  • USB-connect the Arduino UNO and upload the "BareMinimum"-sketch with Arduino IDE software, so nothing disturb the flasher software. (Find the BareMinimum in "File" > "Examples" > "01.Basics" > "BareMinimum")

  • Take note of what COM-port the Arduino UNO use. (See your COM in "Tools" > "Port:")
  • Close Arduino IDE after upload and unplug power/USB.
  • Wirring the ESP8266 to the Arduino UNO as pictures above shows.

  • Connect the Arduino UNO to USB again.

  • Download flasher-software and the firmware BIN-fil here :

  • Unzip the files into a folder, and run the flasher software (esp8266_flasher.exe)

  • Click on the "BIN"-button and find the BIN-fil (v0.9.2.4 AT Firmware-ESPFIX.bin) in the folder.

  • Check whether it is the correct COM port or change it to the correct port.

  • To start the upload/flashing, Click on the "Download"-button
  • If everything is runs, will the flasher software show you the status of flashing and the blue LED on the ESP8266 will blink very fast.

  • If: Failed to connect, just try unplug USB and replug the USB again and click on the "Download"-button again !
  • In the end at 99%, it will show some error but this is ok.

  • The ESP8266 has now firmware version: !!!

Step 2: Rewiring

  • Unplug power/USB.
  • Rewirring the ESP8266 to the Arduino UNO as pictures above shows. VERY IMPORTANT !!!
  • Download the "ESP8266 library" here :

  • Open the Arduino IDE software and import the library (click "Sketch" > "Include Library" > "Add ZIP. Library..." > find the -file and click "Open")
  • USB-connect the Arduino UNO again and upload the "send_email_smtp"-sketch with Arduino IDE software ("Files" > "Examples" > "Adafruit_ESP8266-master" > "send_email_smtp")

  • Now just see this YouTube video
  • And adjust the same things as he does. :-)



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Any one help? it always shows hard reset... no response from module. Why??

Some of the esp8266 boards can tolarate 5v logic level. I could tried about 20-25 pieces of esp8266 board . Some of them has got white rectangle drawing on the surface around the pinouts and they can tolarate 5volt. Others can not tolarate.In the first picture you can see these white rectangle on the esp8266. This esp8266 can tolarate 5v. But in the second picture we can not see that white rectange and probably that can not tolarate 5 volt.. 5 volt can not make them burn you can use them in the projects with 3 volt level..

I have followed all steps carefully as above. But after uploading program, when I open serial monitor it always shows :

Hard Reset...'
no response from module.

please help

1 reply

I also collected the same buggy code. Can someone fix it?

Arduino ide terminal writing : not module connetc.
Pls help & send my email to info


Rx (Arduino) - Tx (ESP)

Tx (Arduino) - Rx (ESP)

Hello, I have detected an error in the first image showing the pinned, you have to rotate the order of RX and TX so that there is communication between the ESP8266 module and the serial / USB port and can display data in the console of the IDE.

Greetings from Andalusia (Spain)

I keep getting this error. Any idea?? I changed HELO TO EHLO but nothing happened. :/

Στιγμιότυπο οθόνης (789).pngΣτιγμιότυπο οθόνης (792).png

In serial monitor I have "Hard reset...'

no response from module." Could someone help me please?

hi, may i know whether the connection of esp8266 to arduino mega is the same as the connection to arduino uno?

class Adafruit_ESP8266' has no member named 'cipSend'

plz help me to solve this problem?????


3 replies

hye, have you fix the error yet?

Have you tried changing HELO to EHLO? There are a number of causes of this error so we'd need to see more of your code.

Have you tried changing HELO to EHLO? There are a number of causes of this error so we'd need to see more of your code.

I wasted my 2 esp on this tut. Every time it falshes .ESP does not repond on AT. What should i do??

1 reply

Have you tried changing the baud rate in Serial Monitor? I had to test a bunch of different rates until 57,600 worked. Also, make sure you change the wiring back after flashing as described in directions.

Try changing HELO to EHLO. It worked for me.

Writing at 0x0007e400... (99 %)

Writing at 0x0007e800... (99 %)

Writing at 0x0007ec00... (99 %)


Failed to leave Flash mode

This is fine. My Module stopped responding after Update :D