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Questions tagged [nodemcu]

For questions about NodeMCU, an open source IoT platform which includes firmware for running on the ESP8266.

567 questions
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Does the Node MCU v3 (LoLin) not have a builtin led?

Trying a simple led blinking program I could not get the builtin led on a LoLin Node MCU v3 working. The LED_BUILTIN constant is set to pin 16 / GPIO16 / D0. Reading several articles and QA I think that the Node MCU boards are supposed to have a the…
Jan H
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Vin & VU pins of NodeMCU V3

Can we use the vin pin of the lolin v3 nodeMCU as a 5V supply. If yes, i checked mine with a multimeter. At max, it gives a voltage of 2V. Is my pin blown out? Also, can use the VU pin as a 5V supply? Will using it cause any problems to my laptop's…
Yash Shah
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Why Smart Plugs don't require setting port forwarding on router and how to accomplish this with NodeMCU (ESP8266)

I have a NodeMCU (ESP8266) board that I use to control some devices over the internet. To be able to access it I have to enable port forwarding on my router and set the port manually like in the image below: But with Smart Plugs (that use a cloud…
Slaven Tojić
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3
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Use 5V pH sensor with 3.3V NodeMCU

I'm trying to use a pH probe with NodeMCU, the problem is that NodeMCU is 3.3V and the pH analog sensor requires 5V, at first I thought using the VIN pin but didn't work, then I used the VU pin from NodeMCU V3 (by Lolin) but it didn't give me the…
Javier Guerrero
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2
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esp2866 powered externally not working

I got a beginner level problem. I got two esp2866 nodeMCU, they both work with the usb cable and I can get the blink program to run though it. Running them with external power doesn't seem to work though. I expect the blink program to run when I…
bhenriksson
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1 answer

NodeMCU serial port - use with computer and device at the same time

I'm trying to understand how serial communication for ESP8266 in NodeMCU actually works. I found a quote saying that normal Serial is mapped to ports GPIO 1 (TX) and GPIO 3 (RX). They are even labeled on the board like this, so I believe this is…
kubal5003
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4 answers

ESP8266 NodeMCU first WS2812 LED lights up green

I'm trying to power some WS2812 LEDs from my ESP8266 ESP-12E NodeMCU board (circuit here). I'm simply trying to use the NeoPixel Strandtest which works perfectly on my Arduino UNO with the same LED strip, but when I change the #define pin 6 to…
MortenMoulder
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1
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Code uploading error on NodeMCU v3 "the selected serial port _ does not exist on your connected board"

when trying to upload code to NodeMCU v3, sometimes I get the error "the selected serial port _ does not exist on your connected board" and sometimes "timed out waiting for packet header". My attempts for this problem: No cable is connected to any…
Wraithdev2
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Is it possible to access GPIO9 and GPIO10 as DIO?

I have a nodemcu dev board with the esp12 chip. (Not the esp12e one). I have tried to make use of gpios 9 & 10 for digital output. On the board, they are marked as SD2 & SD3. I suppose they must be serial data pins by default. Ideally you can change…
deostroll
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How many output pins do NodeMCU have?

I am trying to build a Smarthome system with NodeMCU. NodeMCU would wire up with relays. How many replays can one NodeMCU control?
will free
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How to send NEO6M gps data to firebase?

I'm using nodemcu and neo6m gps module. I can't send data to firebase. As a library using tinygps++. Can anyone please help me how can i pass data to firebase. #include #include #include "TinyGPS++.h" #include…
Sayedur Rahman
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1 answer

How to power Nodemcu using 12 volt AC to DC adapter?

I am trying to make a small project using Nodemcu. My project is WiFi controlled LED, 2 LED's will blink at the same time. I have successfully uploaded the code and it works fine using USB connection. But I want to power the Nodemcu using 12 volts…
Vikranth N
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Problem with NodeMcu interrupt

I am Using Arduino IDE to program NODEMCU. I am expecting LED should remain ON for 4 sec. But it turns OFF in less than 2 sec. Please can anyone explain me why this happening? Also I noticed that if serial monitor is used, led ON timming changes…
Dattaraj
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NodeMCU current consumption in all modes

I am using NodeMCU for my project.I wanted to know how much current it takes in its all modes like sleep mode,deep sleep mode and also in its wifi modes like station and access point mode. Thanks in advance...
user59858
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NodeMCU 1.0 - Exception 9 `Fatal exception 9(LoadStoreAlignmentCause):`

I am getting this error in my code. Fatal exception 9(LoadStoreAlignmentCause): Using core version 2.4.2 Stack trace Decoding stack results 0x40213e9c: dns_gethostbyname at core/dns.c line 1472 0x40204c21: ESP8266WiFiGenericClass::hostByName(char…
tony gil
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