Questions tagged [nodemcu]
For questions about NodeMCU, an open source IoT platform which includes firmware for running on the ESP8266.
32
questions
24
votes
3
answers
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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 ...
- 643
3
votes
2
answers
464
views
I2C protocol doesn't work properly
I am trying to make I2C Communication between NodeMCU and arduino Uno boards. However it is not working properly. It makes communication for once time when i uploaded code.
Master Device Code(NodeMCU ...
- 55
2
votes
2
answers
5k
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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, ...
- 362
1
vote
1
answer
257
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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'...
- 13
1
vote
1
answer
199
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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/...
- 133
1
vote
2
answers
6k
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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
...
- 362
-1
votes
1
answer
773
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>";
...
- 35
15
votes
4
answers
30k
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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 ...
- 375
6
votes
5
answers
76k
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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 ...
- 575
5
votes
2
answers
4k
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 ...
- 161
3
votes
1
answer
5k
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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 ...
- 149
3
votes
1
answer
2k
views
Why do ESP boards break out the SPI flash pins?
I have an ESP32 development board and a NodeMCU board here. Both breaking out the pins for the SPI flash of the ESP. These pins are mentioned in standard pinout descriptions as must/should not connect....
- 15.3k
2
votes
2
answers
24k
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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 ...
- 29
2
votes
1
answer
6k
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nodeMCU - Millis() - Simple Counter - How long is LED on?
PROGRESS, now I have this (WITH GREAT HELP):
void setup() {
Serial.begin(9600);
// initialize digital pin 13 as an output.
}
uint32_t timer_start = 0;
int timer_running = false;
void loop()
{
// ...
- 23
2
votes
1
answer
345
views
NodeMCU Power supply
I got a question about externally powering my NodeMCU V3. It has an onboard voltage regulator (3v3) which breaks out to 3 header pins. Now I want to power 3v3 from an external board. Can I supply 3v3 ...
- 49
1
vote
0
answers
827
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 ...
- 11
1
vote
1
answer
436
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 ...
- 215
1
vote
1
answer
10k
views
What is the use of reserved pins and SDD2, SDD3 pins of the NodeMCU?
How to use the reserved pins on the NODEMCU? What is their use? Also what is the use of SDD pins?
Thanks.
- 143
1
vote
2
answers
3k
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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 ...
- 113
1
vote
1
answer
846
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 ...
- 121
1
vote
3
answers
16k
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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 ...
1
vote
2
answers
28k
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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 ...
- 129
0
votes
2
answers
5k
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NodeMCU V3 + SD Card with Arduino IDE Not working
I am trying to connect CATALEX MicroSD Card adaptor to new NodeMCU V3 and PIN configuration are as below,
NodeMCU ---------> SD Card
GPIO13 (D7) ------> MOSI
GPIO12 (D6) ------> MISO
GPIO14 ...
- 3
0
votes
6
answers
13k
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 ...
- 129
0
votes
2
answers
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 ...
- 121
0
votes
1
answer
3k
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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 ...
- 185
0
votes
1
answer
861
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?
- 19
0
votes
1
answer
1k
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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: ...
- 362
0
votes
1
answer
9k
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 ...
- 111
-1
votes
2
answers
6k
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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 ...
- 11
-1
votes
4
answers
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 ...
- 177
-1
votes
1
answer
2k
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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 ...
