Connecting Arduino mega and ESP-01 to Blynk app

i have project that already work on Arduino mega
i just need to show some values on blynk app
i have Esp-01

and arduino mega

and my iPhone to test blynk app

can anyone replay with simple demo of sending data to blynk app
my TX0 & RX0 connected to nextion display so i need to connect the ESP-01 to TX1 & RX1

note: i didn’t do anything to ESP-01 and don’t know how to the connection is
thank you

This is probably a good starting point…


thank you pete
all clear in ( Connecting an Arduino Mega to an ESP-01 )
but the connection is not clear at all
is there Arduino to ESP-01 connection guide ?

Search the forum or do a Google search, you’ll find what you need.


found this connection on Arduino project hub

" ESP8266:____________ Arduino MEGA:

  • GND -------------------------- GND

  • GP2 -------------------------- Not connected

  • GP0 -------------------------- Not connected

  • RXD -------------------------- TX

  • TXD -------------------------- RX

  • CHPD ------------------------ 3.3V

  • RST -------------------------- Not connected

  • VCC -------------------------- 3.3V "

looks good mr.pete ?

Yes, other than the RXD/TXD connections as discussed earlier.


1 Like

i did like the topic you replayed to me

the code

#define BLYNK_TEMPLATE_ID "T**************U"
#define BLYNK_DEVICE_NAME "test"
#define BLYNK_AUTH_TOKEN "x********************************G"

// Send Blynk user messages to the hardware serial port…
#define BLYNK_PRINT Serial 

#include <ESP8266_Lib.h>
#include <BlynkSimpleShieldEsp8266.h>

char auth[] = BLYNK_AUTH_TOKEN;

char ssid[] = "Moh’s iPhone";
char pass[] = "****************";

// Define your ESP8266 baud rate:
#define ESP8266_BAUD 38400

// Tell the Blynk library to use the  Hardware Serial port 1 for WiFi..
ESP8266 wifi(&Serial1);

void setup()
  // Initialise the debug serial port

  // Initialise the Hardware serial1 port…

  Blynk.begin(auth, wifi, ssid, pass);

void loop()

still the device is offline in blynk website

serial monitor print this

19:37:44.195 → ___ __ __
19:37:44.195 → / _ )/ /_ _____ / /__
19:37:44.195 → / _ / / // / _ / '/
19:37:44.195 → /
//_, /////_
19:37:44.195 → /
__/ v1.0.1 on Arduino Mega
19:37:44.195 →
19:37:44.706 → [517] Connecting to Moh’s iPhone
19:37:45.685 → [1527] ESP is not responding

Which Mega pins are the ESP-01 connected to?

Are you sure that this is the correct baud rate?


ESP —> Mega

3.3v —> 3.3v

EN(CH_PD) —> 3.3v

RX —> TX1(18)

TX —> RX(19)


GPIO0, GPIO2 and RST not connected

Have you tried using an external power source ?

No but the ESP-01 is blinking Blue light
looks like the power is delivered


at 38400

at 115200

i copied the code for Connecting an Arduino Mega to an ESP-01 from

do i need to edit ?

Try this

#define ESP8266_BAUD 9600

Instead of

#define ESP8266_BAUD 38400

same thing

20:07:01.446 → [517] Connecting to Moh’s iPhone
20:07:02.474 → [1527] ESP is not responding

i’m looking online and found that ESP need to get flashed
i didn’t do anything to my ESP-01

just connected it to my arduino mega and uploaded the code

You seem to be getting confused between the serial baud rate that you’re using for debugging, and the baud rate that you’re using for communication with the ESP-01.

The ESP-01 needs to be running the factory AT firmware. If it’s a new ESP-01 out of the packet then it won’t need anything doing to it.

If you’ve previously uploaded a sketch to the ESP-01 then the AT firmware will have been overwritten and you’ll need to restore the AT firmware. All of this is explained in the tutorial I linked you to.


so what do i need to do for successful connection to blynk

Establish whether your ESP-01 is running the AT firmware, and what baud rate it’s using.
An FTDI adapter is the easiest way to do this.


don’t have it
is there a certain name for this process so i can search and determine what is firmware and the baud rate ?