Questions tagged [nodemcu]

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

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58 views

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 ...
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280 views

HX711 with NodeMcu

I am trying to make a scale that measuring weight. In internet i did some researches so i got some questions. I have this module as a HX711 And square 3 wired loadcells( Red,White,Black Wired). My ...
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1answer
573 views

NodeMCU max draw

1) what is the max draw I can draw from NodeMCU V3 logic and 5v pins? 2) Also, I heard i draw with it more than 500mA, the PC USB port stops working. Is that information actual? Because USB 3 port has ...
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2answers
62 views

nodemcu GPIO6 clock

is there a way that i can declare gpio6 (CLK) as an input without getting a wdt reset? I'm somewhat new to circuitry, but my boss wants to use it(GPIO6) to talk with external devices. I have more ...
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1answer
154 views

MQTT with OLED realy :- display not coming properly

I am very new to Arduino/ESP and I am writing a code to activate 2 relays using MQTT. Also like to display status on OLED here is my code #include <ESP8266WiFi.h> #include <ESP8266WebServer....
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1answer
2k views

How to get current Date [closed]

How to get Current date, month and year. I have used RTC, NTPClient, but it didn't work. This gives default output of 1970. What can I do for fixing it. time_t now = time(nullptr); struct tm* newtime ...
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1answer
146 views

NodeMCU MQTT getting topic but not calling IF loop

I am very new to Arduino/ESP and I am writing a code to activate 2 relays using MQTT. My connection is successful and I am able to receive message/topic printed out on serial console. Here is my code: ...
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0answers
932 views

Nodemcu single server with 2 clients

I am trying to connect my nodemcu server with 2 nodemcu clients. One client is connected and it works perfectly. I am unable to configure what to do for the other client to be connected and share data ...
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3answers
129 views

How can one reset Arduino Nano from NodeMCU?

If one connects the RESET pin on an Arduino Nano to a digital pin on a NodeMCU, will the NodeMCU be able to reset the Nano by setting said pin to LOW?
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2answers
62 views

Do comments occupy space in compiled C++ sketch? Arduino / NodeMCU

I tend to leave old code around as comments until I am sure that my current version is stable. Just the way I like working. I am concerned that I may be unnecessarily bloating up my sketches. Do ...
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1answer
74 views

Communication between three NodeMCUs such that one in in AP mode, second one in AP+STA mode and the third NodeMCU in STA mode

I am able to establish a connection between first and second NodeMCU, but unable to do so for the third nodeMCU. I used the IP address to establish connection. Should I assign a different IP to each ...
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1answer
706 views

Nodemcu Server with multiple sensors

I am trying to connect my nodemcu client with nodemcu server, while my client is connected with two sensors (DHT11 and Soil Moisture) and it is workign perfectly, but on the server side I am unable to ...
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1answer
1k views

Soft wdt reset error on NodeMCU (ESP8266)

I am getting error on Serial monitor Soft WDT reset. I decoded the error code also and found the following stacktrace. I am using SIM808 module and DFRobot_sim808 as the library. 0x4010030d: millis ...
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0answers
129 views

How to make watchdog and automatically reset on esp8266

When my system is confronting at logical & hardwaretical problem, I want to make system know It has some problem and reset automatically because my esp8266(nodeMCU) is on the place where people ...
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0answers
43 views

Nodemcu POST Response “-1”

Nodemcu device is returning HTTP response -1 for a POST request on django rest api. I tried the below http request to Postman, and it works perfectly fine. http://localhost:8000/api/datalogs/?plant=...
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1answer
95 views

Communicate between 3 nodeMCU

How should I verify the communication between three node MCUs where one behaves as server and the other two as clients such that data of each node mcu is obtained on all three?
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0answers
73 views

NodeMCU v2 - Current when powering from VIN

I am working on a project and I want to directly power my NodeMCU from VIN. I have found lots of articles and questions talking about different voltages on the VIN pin of the NodeMCU, but almost none ...
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1answer
8k views

WebSocketsServer.h: No such file or directory

I'm trying use the NodeMCU WebSocket. I downloaded the required libraries from: https://github.com/Links2004/arduinoWebSockets and pasted them in my Arduino libraries folder. I uploaded my code but ...
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1answer
398 views

External power supply to 4 channel 5 volt relay

i am from india. I have a question. can i power up a 5 volt 4 channel relay module with a 5 volt 0.7-0.8 mAh wall type charger, which is basically use for charge the simple mobiles. If yes, then how i ...
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0answers
351 views

DHT11 sensor reporting all null values

I am using a DHT11 sensor attached to a NodeMCU ESP8266 to have a web server reporting the local humidity and temperature values. I don't have a resistor attached in the circuit, the DHT11 is directly ...
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1answer
84 views

Running out of GPIO & looking for suggestions

I'm working on a project using a NodeMCU and am quickly running out of GPIO pins. I'm trying to decide which way to go to complete it. Right now, I have the MCU connected to a MAX31856 PT100 ...
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1answer
160 views

SD Card store struct: force big-endian / little-endian?

Following MAJENKO's tutorial on sd card file optimization and data integrity, can I force the SDCard to read and write in either big-endian or little-endian? I need this in order to maintain backup ...
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0answers
54 views

Can I use an RF Receiver to any pin on an Arduino?

I have a project that uses a nodemcu and it includes an rf receiver, I created the pcb board already etc etc... so I've already chosen D7 (GPI013) before reading on connecting the rf receiver and ...
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0answers
2k views

Wemos D1 won't work with MH-Z19B (CO2 sensor)

I would like to connect a CO2 sensor to the Wemos D1. I would like it to work via UART (RX, TX) and not the PWM pin. I've encountered numerous libraries on Github, but I can't seem to get it working. ...
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0answers
281 views

Why am I getting an 'invalid conversion' error on compile?

I have one of these NodeMCU ESP8266 OLED Arduino Wifi Modules which I am trying to load with SpaceHuhn's deauther software from Github I am trying to compile the source code using Arduino IDE with ...
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0answers
39 views

About split string

Sorry my English is poor. I use nodemcu to get a json data. By this String alldata = client.readString(); But it turn this: HTTP/1.1 200 OK Server: nginx Date: Sat, 10 Aug 2019 04:53:16 GMT ...
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0answers
65 views

Node mcu does not connect

im trying to connect to my wifi with mit Nodemcu, i recently got a new router and since then i can't connect anymore. I use simple example sketches from esp library but it will not connect. Instead i ...
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1answer
171 views

I2C master/slave maximum requestEvent message size

Using a NodeMCU master and an Arduino slave (Wire.h on both sides), is there a maximum message size (32 bytes?) for the answer that the slave sends from requestEvent()? If so, is there any solution ...
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1answer
372 views

Programming ESP32 MCUs for production

Before committing to learning about the ESP32 and how to program it, I would like to know if the ESP can be programme the same way for production as it can on évaluation boards (with the Arduino IDE). ...
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1answer
693 views

ESP8266 spend 10mA, even though It is in the deep sleep mode

I am using Nodemcu ESP8266. I want to know how much my ESP board consume the battery during sleep mode. as the Mannual said it spend about micro-ampere, but my multi meter said it spend 10 mili-ampere,...
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0answers
50 views

AT Commands with NodeMCU

I have an NodeMCU with an ESP8266 32Mbit, I am trying to flash the AT Firmware as described in Non-OS AT Instruction Set with NONOS-SDK-3.0 but I dont get any responses. I have the MCU connected by ...
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2k views

input from push button

I have connected three push buttons to node mcu which are working properly, but display of output on COM port is very slow. It works properly when two buttons are connected, but not when three are ...
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1answer
678 views

How to send UDP data packet between two access point?

I am new to arduino programming and nodeMcu boards.I have two ESP8266 bards as access points and one board get some data form WiFi stations and resend that data to other access point. but the problem ...
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1answer
352 views

NodeMCU: Wiegand not working for one device, while working for another

I'm using a NodeMCU, and a working code for reading Wiegand data, with this library. I managed to successfully read the Wiegand signal from this device. However, I also have this new AR-721H device, ...
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2answers
636 views

Lipo Battery level display using nodemcu

I'm designing a connected collar for pets for a project, for this I am using a nodemcu on ESP8266 powered by a Lipo battery I'm guessing around 1000mAh of capacity is enough for a respectable autonomy ...
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0answers
35 views

How to re-send UDP data packet to a esp8266 board? [duplicate]

I have several connected esp8266 boards. Lower level client boards connect to middle level esp8266 board and middle level board connects to the top level Esp8266 board (AP).When a client sends UDP ...
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1answer
450 views

NodeMCU Exception 28 - intermitent problem

I am SOMETIMES getting exception 28 when running a web upload (over a very unstable rural internet CPE link - wifi is fine, but feed goes on and off): Decoding stack results 0x40213b8c: ...
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2answers
373 views

Reset NodeMCU master from Arduino slave

I designed a PWS (personal weather station) which will be placed in a difficult to access location. In case of the master crashing and not requesting from the slave for a certain amount of time (stay ...
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2answers
3k views

Arduino slave with 2 masters sharing the same I2C Bus?

Consider a scenario where two (or more) master devices (the NodeMCU's, in this case) share an I2C bus with one (or more) slave device(s), like thus: Would this be a feasible setup? In other words, ...
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1answer
106 views

NodeMCU what is my esp3286 core version

How do I find out what my esp3286 core version using Arduino IDE?
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1answer
3k views

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 ...
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1answer
127 views

NodeMCU backup sketch

Is it possible to extract a backup of the sketch uploaded to a NodeMCU (as I know that it is possible to backup the firmware). If so, using which tools?
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0answers
649 views

error compiling for board node MCU 1.0

Arduino: 1.8.9 (Windows 10), Board: "NodeMCU 1.0 (ESP-12E Module), 80 MHz, Serial, 115200, 4M (3M SPIFFS)" In file included from C:\Users\Priyaranjan Tiwari\Documents\Arduino\007mcu_php\007mcu_php....
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1answer
435 views

ESP - Nodemcu amica - attachInterrupt crash program

I get new boards from the shop but they are little different from the previous version. I got software what works ok on Nodemcu lolin v3 now I get Nodemcu Amica what is almost same board but if I got ...
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1answer
3k views

NodeMCU keeps disconnecting

I have made a home automation system consisting of a NodeMCU, 4 channel relay board running on Blynk and IFTTT. At the moment I'm only controlling a string of fairy lights and two LED strips from it, ...
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1answer
819 views

How to acheive fast and reliable communication between NodeMCUs?

I have two NodeMCU which have to send data to a server (also a NodeMCU). I want to acheive speed of atleast 10Hz because the sensor sends it at that rate. I have tried websockets and couldn't get ...
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0answers
30 views

Same software on single ESP-12f slower than on NodeMCU

I have programmed a small software to control an LED strip using an esp. I've written a web app which sends a request to the esp which then applies the color. So far everything works, but I've got a ...
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1answer
540 views

Arduino IDE doesn't pick up serial ports

I am fairly new to Arduinos and I recently bought a nodeMCU Amica esp2866 for this tutorial. I have my board connected to my MacBook Air (10.14.5 with Mojave) and only the "/dev/cu.Bluetooth-Incoming-...
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1answer
299 views

http.POST is not sending data to local web page

I am using a nodeMCU to send data to my local web page developed using Spring boot but when I run the code I don't get an error the esp8266 connects to WiFi but I don't get anything on my spring boot ...
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2answers
7k views

Multiple libraries were found for “WiFiClient.h” using nodemcu

I am trying to send HTTP requests from nodemcu so I started by uploading the esp8266 library but when I run the following code #include <ESP8266HTTPClient.h> #include <ESP8266WiFi.h> ...

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