How i can send my data from nodemcu to arduino via serial?

[StefanL38]

@tanishqc

it did not work for me nothing showned in serial monitor

@tanishqc

You have to provide detailed information if somebody shall be able to help you
In this case detailed information means

both actual used complete sketches
The nodeMCU-sketch and the Arduino-sketch

a hand-drawn schematic how you have things wired together

without this informations all is guessing in the fog

[horace]

here is a photo you can see the link between the UNO pin 2 and NodeMCU pin D4

the Node MCU serial monitor displays

ESP8266 HardwareSerial transmit test port 1 pin TXD1 17
test 1 from NodeMCU
test 2 abcdefgh
test3 1234567890

and the UNO serial monior displays

SoftwareSerial test
test 1 from NodeMCU
test 2 abcdefgh
test3 1234567890

in both programs the Serial output is at 115200 baud - make sure your serial monitors are set to 115200baud

[StefanL38]

@horace your circuitry is missing a connection between ground of the nodeMCU and the ground of the Arduino.

It might be that there is a connection because the USB-cable has ground.
But you should always wire the ground of microcontrollers directly

[horace]

you are correct - it is called being lazy!

[StefanL38]

I still have the question if you have a not yet connected IO-pin on the nodeMCU

And YES of course there is a free IO-pin. exactly that one that you are using for the serial connection.

So if the buzzer is really the only thing that the arduino shall make buzzing and nothing else you can use exactly this io-pin for the buzzer

It might be that a transistor is needed to drive the buzzer if the buzzer draws more than 2 mA. But you don't need the arduino

[tanishqc]

but is there a way to make buzzer buzz from arduino side?

[StefanL38]

setup software serial with 9600 baud on nodeMCU
define software serial with 9600 baud on arduino
connect nodeMCU and Arduino with datapin
and with ground!

steps to get there

nodeMCU software serial at DuckDuckGo

[tanishqc]

i did not get it could please help me in detailed explanation so that i can understand

[tanishqc]

I tried but i only get printed 'Software Serial Test' on Serial Monitor of Arduino.

[tanishqc]

Let it Be i m closing this question now because i get it what to do and it worked now so i dont need your help so byee if you want to know what i did for transfering just do message me.

[Pufuldin]

Upload the sketch and send messages using the Serial Monitor. Open the Serial Monitor by clicking the Monitor icon (see Recipe 4.1) and type a digit in the text box at the top of the Serial Monitor window. Clicking the Send button will send the character typed into the text box; you should see the blink rate change.