Questions tagged [nodemcu]

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

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17
votes
3answers
93k views

NodeMCU - Vin pin as 5V output?

I know that Vin can be used to power the board but have also been reading that it can be used as a 5V output. Is it possible to assign Vin as an output as I would any other GPIO? If I want to power ...
2
votes
4answers
18k views

EEPROM put and get not working on ESP8266 (NodeMCU)

The Arduino documentation provides two examples to store data in the EEPROM. https://www.arduino.cc/en/Reference/EEPROMPut stores data in the EEPROM and the EEPROMGet example reads the data back and ...
2
votes
1answer
499 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 ...
1
vote
1answer
57 views

NodeMcu 1.0 resets automatically after sometime

I want to show some digits in a 3x3 p10 red led pannel where the number will come from the cloud and the number keeps updating. For this I have used esp8266 based Nodemcu. I have used WiFi Manager ...
1
vote
1answer
184 views

NodeMCU not responding AT after blink app

I've just bought NodeMCU LoLin ESP8266, I tried to send AT commands (after spending days on ESP8266-01) and everything was okay. Than I've uploaded the Blink example to the board, after that moment it'...
1
vote
1answer
158 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/...
0
votes
2answers
2k 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, ...
-1
votes
1answer
615 views

NodeMCU and expected ';' before wrong ' " '

I am creating a home weather station but the Arduino IDE shows "expected ';' before 'viewport'". It detects wrong quotation marks. My code: String message2 = "<!DOCTYPE html>"; ...
4
votes
5answers
66k views

How to make a 5-volt relay work with NodeMCU?

I have hooked up 2 channel 5-volt relays with NodeMCU v1.0 as shown in the fritzing below. Relay are powered with a different power source than NodeMCU. As of now, I am powering the NodeMCU from my ...
12
votes
3answers
38k views

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 ...
15
votes
4answers
26k views

ESP8266, Arduino IDE vs Lua?

I'm planning to buy an ESP8266. Do I really need to learn Lua to play with it? I have seen some people using it with the standard Arduino IDE. Do you need a custom firmware to use the Arduino IDE ...
1
vote
2answers
23k views

NodeMCU power consumption measurement and DeepSleep

I'm working on a project using a nodeMCU using a ICR14500(3.7V and 700mAh) battery and I'm experienced some issues when I try to estimate the total current consumption. Firstly I experienced some ...
0
votes
1answer
560 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?
2
votes
1answer
108 views

NodeMCU wiring for Serial1?

I'm trying to get telemetry data to be sent out Serial1 on the NodeMCU board. I read that TX is (by default) mapped to pin D4. Ultimately, there will be a Raspberry that will be listening for ...
2
votes
1answer
4k views

NodeMCU does not boot up when GPIO pin is high

I have a NodeMCU board connected to a door and there is a micro switch that makes one GPIO pin (GPIO15 - D8 in this specific case) go high when the door opens. My problem is if I lose power while the ...
1
vote
0answers
485 views

Can someone help me to change this code to u8g2

I would like to change this clock to u8g2. It works fine with the esp8266 and oled 128x64. I would start by including the u8g2 library with #include and all display. with u8g2. replace. What else ...
1
vote
3answers
15k views

Communication via IP adress with Arduino IDE and ESP8266

I have two Arduino boards and two ESP8266 modules with the NodeMCU firmware, and I want to make this: One Aruino will be connected to one module and a vibration sensor, and when this sensor detects ...
0
votes
1answer
2k views

MQTT not working on ESP8266 (Nodemcu 0.9)

I'm trying to use NodeMCU on my ESP8266 (NodeMCU 0.9) but the board keep crashing and I don't understand why. I tested the mqtt broker using command line and it works perfectly, so I can suppose that ...
0
votes
6answers
12k views

NodeMCU powered with battery and use WiFi

I'm running a project with a nodeMCU DevKit and my project runs smooth if I run it connected through the usb wire to the computer. I need to run my project using battery and I tried with a ICR14500 ...
0
votes
0answers
79 views

ESP8266 NODEMCU V3 web server with MAX7219 and DS3231 RTC

I am using ESP8266 NodeMCU with MAX7219 and a DS3231 teal time clock. I want to display the time and some text. The display is made of 4 FC16 modules which are made of 4 8x8 MAX7219 led matrix modules ...
0
votes
2answers
1k views

Sensors go crazy on external power

For few days, I am trying to figure out, why my sensors do not work on external power. I bought NodeMCU along with couple different sensors etc. I was happily working with them, connecting them one by ...
0
votes
1answer
2k 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, ...
0
votes
1answer
2k 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 ...
0
votes
1answer
713 views

YL-38 output to NodeMCU v1.0 analog input

Using a YL-38 and NodeMCU v1.0 I am trying to achieve what the first link is doing, take a soil moisture reading. I've done this on an arduino, but the conversion from an arduino nano to a nodemcu is ...
-1
votes
1answer
7k views

How to fix 12V RGB LED Strip connection to NodeMCU?

I am trying to hook 12V RGB Led Strip (LTROP SMD 5050 RGB LED Light Strip) to a NodeMCU unit. I know there are many different tutorials on this and I am very new to wiring and electric circuits. I ...
-1
votes
1answer
182 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 ...
-1
votes
5answers
3k views

No Response to AT commands

I'm unable to communicate with my nodemcu ESP8266 module using the AT commands. The module does not return 'ready' on the serial monitor and entering AT commands has no effect at all. I am able to ...
-1
votes
2answers
5k views

Serial Monitor not properly interpreting data from my NodeMCU V3

I've just received several LoLin NodeMCUs from a 'cheap Chinese ebay vendor'. They're working well except for the fact that I'm getting garbage in the Arduino IDE Serial monitor. I am able to: Load ...