Questions tagged [nodemcu]

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

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44 views

Connecting NodeMCU through internet [closed]

I have a NodeMCU and a website (free website domain provided by http://www.hpage.com) and I have to send and receive some data (suppose a 8bit number) from the website to the NodeMCU via internet. The ...
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1answer
255 views

NodeMCU Ping working on one but not another

Update 2: Have tested by pinging various devices on different subnets / vlans and did a pcap on the wifi AP I can see the icmp requests going through for each request except for ones on the 4.x subnet,...
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2answers
828 views

What is the voltage between Vin & GND?

I have NodeMCU ESP8266N Lolin V3, my 5V relay is powered from Vin of the NodeMCU. The NodeMCU is powered from 5V USB. My difficulty is when I measure voltage between Vin & GND, it is of 1.9V, but ...
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1answer
43 views

Power Arduino Mega ESP85266

Is it possible to Power a Arduino Mega 2560 and a NodeMCU V2 ESP8266 ESP-12E from a single 9V Block? What would be the best solution? Can i power the ESP8266 directly via the Arduino Mega 5V output? ...
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1answer
68 views

How to trigger NodeMCU sketch from Arduino Leonardo Micro Pro?

So this is probably a very simple question. I have my NodeMCU set up and working where it connects to wifi and sends a push notification. Currently it does that automatically when connected to power. ...
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2answers
321 views

NodeMCU burned, did I something fundamental wrong?

I have a NodeMCU where I connected a LED strip (WS2812b, which operates at 5V). NodeMCU is powered via USB 5V. The used power adapter can supply 2.5A max. I don't have a separate power supply for ...
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0answers
329 views

HTTP PUT method on NodeMCU/ESP8266

I've been trying to send a put request from my esp8266 for a while not but I can't figure out why it doesn't work and there are barely any posts about put requests online I keep getting errors around ...
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0answers
38 views

Can anyone explain this?

starting app without reboot espcomm_send_command: sending command header espcomm_send_command: sending command payload espcomm_send_command: receiving 2 bytes of data closing bootloader ...
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1answer
249 views

Error - invalid conversion from 'char' to 'const char*', Not able to connect on pubnub server using node mcu [duplicate]

I have node mcu with ESP8266 wifi module. When i am trying to upload an example code then its not working. This is the Error:- inline PubSubClient* PubNub::subscribe(const char* channel, int ...
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0answers
233 views

Nodemcu + GSM IOT-GA6

I've connected my NodeMCU to GSM module using GND, RX and TX. I use At Comand Tester. When I try to get sim status or something I get error for example: Unable to get Sim status. Only AT comand ...
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1answer
118 views

How to publish on Pubnub with node mcu?

I have node mcu and i am trying to use the example code on github and pubnub blog to send a msg as an experiment but can't figure how to do it. I used 2 example as the reference - https://github.com/...
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92 views

I want to connect my NodeMcu v3 to gsm

I have a problem with connecting my NodeMcu to gsm. I have bought GSM module but I have sim code on card which I can't and that is the problem because I've found some libraries but there are no ...
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1answer
327 views

How to find the MAC address using NodeMCU when connecting to WiFi?

I am new to using NodeMCU and IOT. I am testing the NodeMCU (ESP8266) so that I can connect with pubnub server. Have taken code from github but there is error saying 'mac was not declared in this ...
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2answers
1k views

Deep Sleep NodeMCU with Door Sensor

I have a very simple code of door sensor (magnetic) which gives results in 1 & 0 format. But I want to run the NodeMCU only when a door is open or close. Rest of time I want to keep it in deep ...
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1answer
218 views

5V 10A 4 channel relay to 2 lights15W light in series in 220V AC supply

I am trying to setup my first relay module with live environment. I have attached the relay module image below. Which I am using to control 4 devices in my switch board as follows: Fan (working ...
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1answer
145 views

The code is working fine with Arduino Uno but not with NodeMCU

I uploaded program MPU6050_DMP6_Multiple.ino (https://github.com/eadf/MPU6050_DMP6_Multiple/blob/master/MPU6050_DMP6_Multiple.ino) to Arduino Uno and it works fine. When I upload the very same code to ...
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1answer
253 views

Detect power interruption on NodeMCU

Im using a 5v 1A power supply and connected to VIN pin on the NodeMCU. I also use 18650 battery to keep NodeMCU running in case the power supply shuts off due to power interruption. I'm planning to ...
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0answers
65 views

Garbage output/ not running at start up nodemcu

I have a nodemcu acting as a thermostat home office. The wall heating element is controlled with a solid state relay on D2. If i have it connected, I cannot program the board from the arduino ide. I ...
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0answers
241 views

NodeMCU with digital sound sensor - Can't find examples or good documentation

I'm very new to this world, and trying to hack one of my first projects have proven hard without solid documentation or examples to copy like I usually do. I've got a https://www.gearbest.com/...
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2answers
54 views

Help to delimit and read specific contents of incoming HTTP string

I am sending strings to an Esp8266 via web browser. The below code returns the following in serial monitor if I send in browser: Send from browser to esp8266 - http://192.168.1.220/s1s2s3s4s5d1 ...
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1answer
29 views

Why is this failing after 3 iterations?

I simply cannot figure this out, why is this failing after 3 iterations? Other than that, what better way is there to do this? Thanks! #define rotary_encoder_topic "/rotary/encoder" #define ...
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1answer
185 views

Can't extract basic data using ThingspeakHTTP

I don't know anything about HTML, but I want to extract the % probability of the Northern lights being visible from this webpage http://aurorawatch.ca/. I entered this into the URL field, and selected ...
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1answer
939 views

Taking String Input from NodeMCU Webpage and Printing it on Serial Monitor

I've started working with NodeMCU recently. I've very little knowledge about this device and how a website works. I'm trying to take a long string input from a website hosted by NodeMCU, store it on a ...
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1answer
121 views

Addressable RGB LED Strip

I am looking to create an addressable RGB LED strip circuit with my NodeMCU v3 Wi-Fi. I am looking at a strip of 150 RGB LEDs, 5 meters long, so 30 LED/m. But I am only going to use about 50 LEDs for ...
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1answer
70 views

Does NodeMCU have some protection against wrong connections that could kill a computer USB?

I know some computer USB could handle some bad connection (by blocking the port, which need to reboot the computer). But I wonder if a NodeMCU 8266 offers some protection.
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1answer
102 views

How to build a wireless pump controller using arduino and esps? [closed]

I want to have automatic control for my pump, wirelessly. A transmitter unit fitted in the water tank would sense the water level and transmit the data to a receiver unit attached to the pump ...
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1answer
175 views

Flashing an ATtiny85 with a NodeMCU?

I recently purchased a Digispark for some of my smaller electronics projects. After it initially being a great little board, I soon found myself unable to flash the board in the same way I had done ...
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1answer
357 views

FastLED: Can't address led individually

I'm unable to access the first led in my strip with this code: void loop() { leds[0] = CRGB::White; FastLED.show(); delay(100); leds[0] = CRGB::Black; FastLED.show(); delay(100); } Instead, it ...
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2answers
181 views

How to / is it possible to change Vendor Name in ESP8266-12E?

I am aware of that it is possible to change hostname for ESP8266 but I want to change vendor name also so that it lists my company/product name in routers/firewalls. Is it possible?
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1answer
320 views

GPRS Based OTA to the NODEMCU [closed]

I need the OTA firmware update. I have the only option in my hand GSM(GPRS SIM800), with the help of this is it possible OTA, plz help me for this how I Do OTA via GPRS, FYI, I completed OTA Via WIFI.
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3answers
2k views

Passive buzzer works with analogWrite(), but not with digitalWrite(). It also has constant static noise

I have a YL-44/MH-FMD passive piezo buzzer hooked up to an ESP8266/NodeMCU. It's connected like this: Buzzer ---> NodeMCU - GND ---> G - VCC ---> 3V - I/O ---> D2 This code makes a clear beep. ...
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1answer
145 views

Communicating with a 12V device?

I'd like to connect a 12V access control device to the Arduino, but I lack the understanding. How can the signals from and to the device be done when they have different voltages? I am afraid ...
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2answers
191 views

NodeMCU ESP8266 12E loses code after power is reconnected

I have uploaded a simple code to control a 8 channel relay by turning individual relays on and off When I upload the code it works properly, the code works properly and the relays turn on and off in ...
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1answer
5k views

How to connect NodeMCU to NRF24L01

I need to connect NodeMCU and NRF24L01. where I'm receiving data from another NRF24L01 Transmission. I managed to connect to a WiFi network but the data receiving is not taking place as expected. Here ...
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0answers
18 views

controll intigers from webserver on nodeMCU esp8266

I would like to controll neopixel leds from over wifi with my nodeMCU but i dont know how to controll values over wifi, through a web interface would be perferable over url, but that also works. usinf ...
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1answer
201 views

Unable to get output on Arduino serial communication with ESP8266 and M6E RFID reader

I am unable to get the output on NODEMCU serial. NODEMCU is connected with Arduino Uno, and Uno is connected with M6E Nano RFID reader. Currently I am unable to understand that am i doing any mistake. ...
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2answers
555 views

How can I update a sketch to a NodeMCU “over the air” with the Arduino IDE?

I’m trying to use a sketch from this repository which uses MQTT to send a notification to Home-Assistant that acts a “presence sensor”. When the NodeMCU comes into range of the specified SSID, the ...
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1answer
480 views

How to convert byte array into a single variable

In this code i am taking the TID data(20bytes of 160bits) in the form of array according documentation and and its working correctly and getting the output of RFID tags. Now I just need your guidance ...
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2answers
3k views

NodeMCU does not connect to wifi

I'm trying to connect my nodeMCU to my WiFi network but it keeps printing ........ which means is not connecting to the network. Here is my code used to connect to WiFi. Any reason why it isn't ...
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1answer
282 views

ESP8266 Peer to Peer with AP and STA - Cache AP Clients, Flush Their Requests?

I'm fairly inexperienced with Arduino and entirely new to networking, so bear with me. I've programmed a couple of NodeMCU devices to communicate the use of an instrument via activation of an LED. I ...
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1answer
61 views

How to know which event fired first?

I want to automate the chicken coop of my grandmother. To do so, I want to use Arduinos and NodeMCUs, respectively. I want to check if all chickens are in the coop at night and then close a little ...
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1answer
617 views

NODEMCU 1.0 HX711 Load cell reading weird text

Hi Guys! i have a problem with the reading with my NODEMCU where i tried this code on an arduino UNO it is working perfectly fine but until i tried to switch it to NODEMCU 1.0 which have a wifi ...
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1answer
81 views

Serial monitor doesn't work with piezo buzzer

So I can't see the distance of the proximity sensor anymore as soon as I type the code for the piezo buzzer. I've tried many things but it doesn't work.. Can anybody help me fixing this? int trigPin =...
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1answer
191 views

How can I connect nodemcu with laptop wifi

Question is odd, but I want to know that how I connect nodmcu with a laptop wifi without using any router. Is it possible if yes then how?
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1answer
396 views

How to connect Sparkfun M6E Nano UHF Rfid reader and ESP8266 NodeMCU 0.1

I am using an ESP8266 NodeMCU v0.1 and Sparkfun M6E Nano UHF Rfid reader. How to connect NodeMCU to M6E Nano UHF Rfid reader?
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2answers
1k views

Circuit diagram for ACS712 and ZMPT101B with ESP8266 using ADS1115

This is probably a cry for help for a circuit diagram which involves connecting ESP8266 with ADS1115 with ACS712 and ZMPT101B(voltage sensor). Since both of them uses analog pins, and using a diode ...
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3answers
839 views

How to integrate nRF24L01 to esp8266 nodeMCU? [closed]

I can't seem to integrate an nRF module to my nodeMCU. I just want to verify my code but an error message keeps popping up Below is the sketch: #include <SPI_Class.h> #include <nRF24L01.h&...
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1answer
661 views

Bridging the wifi networks on nodemcu: how to set the esp8266 as wifi extender, simplest case

It seems to me that humidity is getting high in one room in the basement in my house. To monitor the situation temporarily, I would like to build a very small wifi-mesh network to exchange these ...
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1answer
54 views

Accessing raspberrypi.local from Nodemcu

Currently I am trying to access a rest API from NodeMCU. The API is hosted on my local LAN on a Raspberry pi 3 b. The Raspberry pi is accessible on LAN using the raspberrypi.local domain address. But ...
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1answer
338 views

ESP8266 too many argument to function

My project uses ESP8226 to allow: 1) user to set an alarm. 2) after 20 sec of the alarm ringing, it will notify to phone via blynk app using motion sensor. 3) after 40 sec it will turn off ...