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Questions tagged [nodemcu]

For questions about the NodeMCU open-source Internet of Things (IoT) platform. Use in conjunction with the "iot" tag.

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ESP8266 NodeMCU SD Card Not Initializing

I have tried numerous tutorials, Arduino examples and I cant get an SD to initialize. There is a card inserted that is formatted with exFAT and there is one file test.txt. Particularly https://www....
Jason Crosby's user avatar
-1 votes
1 answer
57 views

Why do my motors run slowly and then stop when powered by two 9V batteries in parallel through an L298n motor driver with a NodeMCU ESP8266? [closed]

I am currently working on a project that involves controlling four dual-shaft DC geared motors (the yellow ones.) I am controlling them with an L298N motor driver through a NodeMCU ESP-8266. I have ...
arun's user avatar
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1 vote
0 answers
56 views

ledcWriteTone leaking to other pin?

I've recently written a program that involves two blinking LEDs. I have these LEDs wired straight from the pins into GND. One is set to blink on and off on one second intervals, and the other is fed a ...
Colby Johnson's user avatar
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0 answers
53 views

Voltage/current issue in a circuit

I am working on a project where I have a 3.7 V battery connected to a SIM module. The battery has a maximum voltage of 4.2V and a cutoff voltage of 2.65 V. A NodeMCU is also connected to the circuit ...
Solo's user avatar
  • 45
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0 answers
36 views

NodeMCU v0.9 - ESP8266-12 MicroPython Unable to access REPL (Python prompt)

I have a NodeMCU v0.9 which I have successfully flashed MicroPython on. I can't access the REPL using any of the methods listed on micropython docs - (picocom, thonny...).. I'm able to access the ...
Sadiq Salau's user avatar
1 vote
0 answers
128 views

Power issues with Nodemcu and Sim800L

I am building a project and i am facing weird anomalies while implementing it. Keep in mind in a student a fairly new to this. So the problem is that i have a usb- charging module connected with a ...
Solo's user avatar
  • 45
0 votes
1 answer
130 views

NODE MCU/ESP8266 interrupts issue

I am using esp8266 to calculate the rpm using hall 3144 sensor, and while doing so there is an issue arises in code. ...
Ryu's user avatar
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0 votes
1 answer
185 views

Voltage regulation for NodeMcu

I am trying to develop a custom PCB with the esp12-E module. For development and testing, I am using the nodemcu development board ESP8266 V3. I am powering the nodemcu via a 3.7V battery with a ...
Solo's user avatar
  • 45
2 votes
3 answers
63 views

Cutoff Voltage of Battery and Minimum input voltage needed by Voltage Regulator

I am working on a project for school and I'm having trouble identifying some variables. I am fairly new to electronics and need some guidance. I am trying to power a nodemcu via a Li-po battery rated ...
Solo's user avatar
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0 answers
55 views

Issues with Nodemcu, LoRa Module (Lora-02), and Bluetooth Module (Hc-05) for SMS Communication

I am currently working on a project that involves using an node mcu, a LoRa module (Lora-02), and a Bluetooth module (HC-05) to enable the transmission of free SMS between two mobile devices when ...
ElectronicGuy's user avatar
1 vote
3 answers
366 views

How to connect WS2812B strips to all show same animation?

I have a 3 meter WS2812B strip that I want to connect to a NodeMCU in a very specific way. I want to cut the strip down to six 20 cm segments but I don't want the animations to "snake" from ...
John Anderson's user avatar
0 votes
1 answer
111 views

As in the picture when I connect the gnd of hlw8012 to the gnd of esp8266 I get electric shock .what should I do now

I'm working on a project based on Iot so I was using hlw8012 for power monitoring and after connecting the IC module to the esp8266 whenever I touch the Esp module I get electric shock . What should I ...
Tony's user avatar
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0 votes
0 answers
189 views

NodeMCU / ESP8266 died

I created the attached circuit. It's about as simple as it gets, 4 buttons (2 low since GPIO pins are pulled up, and 2 high or low depending on whether they're pressed), a stepper motor controller, ...
Matthew Shaile's user avatar
0 votes
1 answer
209 views

How to protect a relay from power surge?

simulate this circuit – Schematic created using CircuitLab I am trying to control an LED bulb using a solid-state relay, the problem is, the bulb is flickering from time to time, if it is turned ...
Ahmed_4EGA's user avatar
0 votes
2 answers
265 views

Controlling LEDs with MOSFETs

I am working on a hobby project in which I am controlling two rows of LEDs. Each row has 5 LEDs in series. I want to achieve the logic drawn in this table: Can anyone suggest any MOSFET logic to ...
ROBERT's user avatar
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0 answers
823 views

Why am I getting 255 for all NPK values?

I am using a NodeMCU ESP8266 WiFi board for collecting N - P - K sensor data. I am using RS485 as interface. This is the code: ...
Steve54's user avatar
0 votes
1 answer
79 views

NodeMCU/ESP8266 with 2 relays doesn't work

I have the schematics below in which one of the relays work fine but the other doesn't, from design perspective they are the same! The relay at the bottom is the one that is not working: And this is ...
Ayman's user avatar
  • 3
0 votes
0 answers
343 views

Modbus RTU on ESP8266 to control VFD

Hoping to get some help on setting up a NodeMCU (esp8266) with this 1 arduino library to control a Variable Frequency Drive (VFD). I'm afraid to say that I almost need help from square one, as I'm ...
Christian Carlsson's user avatar
3 votes
2 answers
713 views

Where is the flash memory on the NodeMCU ESP8266 v3?

In the NodeMCU v3 specs it says it has 4Mb flash memory. In the ESP-12EX datasheet it says the MCU has no rom, but can boot from an SPI external memory. However, I don't see any flash memory chip on ...
hl037_'s user avatar
  • 133
0 votes
1 answer
596 views

Why does the DS18B20 temperature sensor require a stronger pull-up resistor when Node MCU is powered through the Vin pin?

I have a DS18B20 temperature sensor connected to a Node MCU (ESP-12 / ESP8266) like shown below, where μP is the MCU (any GPIO gives the same result) and Vpu = VDD = 3.3 V, coming from the 3.3 V pin ...
guiweb's user avatar
  • 121
2 votes
1 answer
52 views

Will L7806 work with NodeMCU?

I have a NodeMCU LUA Lolin V3 with an ESP8266 -12E. I want to know if I can use an L7806CV votage regulator with it through the VIN pin? The NodeMCU has an AMS1117 3.3 voltage regulator.
abdusalam7474's user avatar
1 vote
1 answer
286 views

How to control my DOL starter buttons (ON and OFF) with NodeMCU of my 1.5 hp motor (motor starter/panel) to control it remotely?

I have been working on an IoT project at home. I have three different tanks with different volumes of water in them. I want to have the levels displayed on my dashboard using a Raspberry Pi. I need to ...
Satyam's user avatar
  • 111
1 vote
1 answer
856 views

Powering ESP32S Node MCU through Vin vs USB

I am having a situation with my ESP32S Node MCU that I can't figure out. I uploaded a sketch to my MCU that will blink the blue LED connected to GPIO 2 every x number of seconds. Here is the sketch <...
random_coder_101's user avatar
1 vote
0 answers
53 views

Driving LED light chain that needs voltage switching

I have some LED party lights with a defect controller. If you power it "+/-", only the odd ones are illuminating, on "-/+" only the even ones. Now I want to drive them using a ...
eltomato's user avatar
0 votes
1 answer
123 views

NodeMCU v3 with TIP120 and DC booster

I have already been through plenty of topics to try to integrate three TIP120s with a DC booster in order to operate two solenoids valves (non-latching NC ones). I think I am getting close but there ...
wr0ng.name's user avatar
0 votes
0 answers
121 views

How can I test WS2812B 5 m 60 LEDs/m with NodeMCU?

I bought this WS2812B 5 m 60 LEDs/m. I want to know if it works properly. I have a NodeMCU 1.0 and I recently bought a 5 V, 10 A adaptor for these but the damn thing still only lights up the first LED ...
Akash Talware's user avatar
0 votes
0 answers
998 views

How to use an MPU 6050 (or any I2C) on different pins on an NodeMCU?

My idea was to have multiple MPU 6050 (6-DOF accelerometer) sensors connected and read by an NodeMCU. I had tested a single accelerometer on the D1, D2 pins and it ...
Iconstrife's user avatar
0 votes
1 answer
277 views

Does running the ESP8266 or any other MCU below the minimum voltage cause damage?

I'm powering an ESP8266 MCU from a 2.5V voltage source that occasionally drops to 2V when a motor runs (runs for about 5 seconds twice a day). The battery is low. Incidentally, the MCU is powering a ...
Nick Bolton's user avatar
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1 vote
2 answers
173 views

Why is this NodeMCU acting like this?

I am experimenting with a NodeMCU. I want to use a push button to give input to the microcontroller. My setup is as follows: simulate this circuit – Schematic created using CircuitLab The ...
UmH's user avatar
  • 111
0 votes
0 answers
98 views

BME280 sensor locks ESP8266 and prevents booting

I have an AZDelivery Node MCU ESP8266 linked via SPI to a Adafruit BME280 Temperature, Humidity and Pressure Sensor that when the data connections are made it prevents the ESP from booting and ...
Byte Insight's user avatar
0 votes
1 answer
59 views

NodeMCU RF522 connection not working

I have a NodeMCU which is connected to a RF522 sensor and a LCD display. I did the connection as follows D4-SDA D5-SCK D7-MOSI D6-MISO GND-GND RST-D3 3V-3.3V LCD-I2C is connected nodeMCU as: GND-GND ...
OISHIK SENGUPTA's user avatar
0 votes
1 answer
29 views

NodeMCU 12E power requirement

On the back of the NodeMCU, it is: Vin +5V Recommended +10V MAX. I can see that it has an AMS1117 voltage regulator. Its datasheet says we can use [4.5V to 15V] ...
kdm6389's user avatar
  • 107
0 votes
1 answer
143 views

Can't connect to a NodeMCU ESP8266

I have a bunch of NodeMCU ESP8266 boards (bought three from here: https://www.amazon.ca/gp/product/B07HF44GBT/), but for the life of me I can't figure out how to actually use them. When I plug them in ...
IronWaffleMan's user avatar
1 vote
0 answers
647 views

ESP32 2 SPI connnection ethernet shield and usb host

Is it possible to have two SPI connection for ESP32 for ESP32 below link for the product https://www.amazon.co.uk/AZDelivery-NodeMCU-CP2102-Development-Parent/dp/B07ZZFXRTY for ethernet shield ...
Rizkis Walker's user avatar
0 votes
2 answers
268 views

Is it important to which GND I connect my relay (OR gate on signals from two different controllers with separate VINs)

I have a power supply (let's say 5V battery) and a NodeMCU (micro-controller) attached to it. I want to turn on the power supply for this NodeMCU #1 by signal from another micro-controller (from ...
PolGraphic's user avatar
0 votes
0 answers
187 views

NodeMcu (ESP8266) pinout problem

I am trying to use a nodeMcu in a project that involves: a microSD card reader (SPI), two devices that communicate with nodeMcu via software serial, a switch and 2 leds. Currently the microSD is ...
patsy2k's user avatar
  • 101
0 votes
1 answer
77 views

Limited WiFi with NodeMCU

I am using the following code to connect with the WiFi router: ...
usman shah's user avatar
1 vote
1 answer
189 views

Connecting optocouplers to pins D3 or D4

I am trying to create a fairly standard setup: controlling 4 channel relay with NodeMCU. I decided to use optocouplers to make connections and generally have everything working now. However I learned ...
michal's user avatar
  • 111
1 vote
2 answers
208 views

Nodemcu: How to extend sensor wires?

I am using a Water flow sensor connected to v2 nodemcu. However, this sensor needs to be placed at a distance of 40 feets from nodemcu, on the 3rd floor of my apartment roof (I stay on 1st floor). The ...
jerrymouse's user avatar
1 vote
1 answer
175 views

how to detect water level using NodeMCU in overhead tank?

I am making a simple water level alarm connected to my V2 NodeMCU. Using the principle of water conductivity. Two wires with stripped ends are dipped into the tank. As soon as the water level reaches ...
jerrymouse's user avatar
1 vote
1 answer
734 views

Providing power to NodeMCU (ESP8266) from the 5 V output of an Arduino

Is it possible to power a NodeMCU from the 5 V output of an Arduino UNO board? I was trying to use the Vin of the NodeMCU as the input from the 5 V port of the Arduino, but didn't work. Could anybody ...
Abdullah Nasir's user avatar
1 vote
2 answers
2k views

LED_BUILTIN output is not working on NodeMCU ESP8266

I have a new NodeMCU ESP8266. I made sure that the builtin LED on it was working properly by uploading the "Blink" example sketch from the Arduino IDE examples and it worked. When I try my ...
Odasaku's user avatar
  • 115
0 votes
0 answers
205 views

What GPIOs in NodeMCU are usable

I am running out of usable GPIOs in my NodeMCU esp8266 board. I'm making a car. For the car I use L298N motor driver with 4 gear motors. The pins of L298N motor driver is connected as like this, 1.ENA ...
Savithu's user avatar
  • 13
0 votes
2 answers
494 views

Powering this circuit off 3A USB charger, but it's only supplying 350mA

I have a very simple circuit for a small RGB lamp I'm building. My plan was to power it off one of my many spare old USB phone chargers via micro-usb. It's just a string of 60 WS2812B LEDs with a ...
Tim Gautier's user avatar
0 votes
1 answer
747 views

How long can I power up a nodeMCU

I have a nodeMCU esp8266 and I'm going to power up the nodeMCU as long as possible but I need to know is it good to the health of nodeMCU. In other way I am going to power the nodeMCU forever.(...
Savithu's user avatar
  • 13
0 votes
1 answer
3k views

Can I power a nodeMCU using 3.7 battery

I have a nodeMCU board (3.3V) and a li-ion battery with 3.7 V. Is it alright to give the power supply from that battery?
Savithu's user avatar
  • 13
1 vote
3 answers
544 views

Wire gauge for sensor at long distance

I am planning for a home irrigation system and confused with the wire gauge required the sensors on the plants. The circuit diagram would be something like below: (Please consider the sensors as ...
Avirup Das's user avatar
1 vote
2 answers
148 views

Understanding what exactly is the NodeMCU

So the NodeMCU looks like this: And the ESP12 is this: So I can see that the little ESP12 is riding on the NodeMCU. my question is: What is included in the ESP12 and what in the NodeMCU, in context ...
YoavKlein's user avatar
  • 235
0 votes
1 answer
2k views

Power NodeMCU from Arduino Uno

I am facing challenge in powering up NodeMCU from Arduino. My Arduino is connected with external power supply (12v). From Arduino, I connected 5vpin to NodeMCU <...
Kalaivanan's user avatar
2 votes
2 answers
5k views

ESP-01 module CH_EN pin confusion

I have a custom board that I have developed where I am using the ESP-01 module. I have not connected the CH_EN pin to GND or Vcc on the board. When I connect the module to the board, the red LED ...
Amorphous's user avatar
  • 169