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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TP4056 - Micro USB 5V 1A - Output pins Current supply

I have "TP4056 - Micro USB 5V 1A Lithium Battery Charger with Protection" as below I have a Li-Ion 3000mAH battery like below Connected them as below Questions: What is the maximum current that I ...
Sridhar Y's user avatar
2 votes
0 answers
1k views

External vs internal pull-up resistor

I'm using an esp8266 to read signals from a water meter. The meter periodically closes a switch between two wires. My prototype circuit works fine with either an external pull-up resistor, or using ...
zwiebelspaetzle's user avatar
2 votes
1 answer
3k views

Esp8266 nodemcu v3 connection to usb fingerprint scanner

My project is about making an ioT biometric attendance management using Esp8266 nodemcu and a Morpho usb biometric scanner. So my question is whether is it possible to connect a usb fingerprint ...
Venkatesh Shiga's user avatar
1 vote
3 answers
118 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
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
1 vote
0 answers
584 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
1 vote
1 answer
4k 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
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1 vote
0 answers
220 views

Adding momentary switch (push-button) to NodeMCU

I want to add 2-pole momentary push-button (switch) for my covers. Integration goes through a NodeMCU and ESPHome. I'm having a hard time understanding the schematics for this switch: I'm not sure ...
lonelydev101's user avatar
1 vote
0 answers
646 views

Problem feeding an ESP8266 and RGB 12V led strip from single source

I have an issue while was trying to feed an ESP8266 nodemcu v3 lolin and a RBG 12V led strip from the same source. When I try to use the same source, I am unable to access this ESP8266 webpage, as ...
marafado88's user avatar
1 vote
0 answers
165 views

PH 4502 electrical interference EMI when in aquarium

I'm trying to get a regular ph reading in an aquarium. The sensor works well when the probe is in a small quantity of water(i.e. a glass) but has large variations in larger water quantities (i.e. ...
gedorin's user avatar
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1 vote
3 answers
1k views

Emergency backup battery supply

I am building a NodeMCU-controlled 12 V solenoid. I am hoping to add an emergency backup battery supply, but the emergency backup supply should not power anything but the solenoid. In other words, if ...
ryan.d.williams's user avatar
1 vote
0 answers
103 views

How to blink LED using NodeMCU in Arduino IDE?

I have alredy installed ESP8266 package in my Arduino library. I connected d0 pin of NodeMCU to LED's positive terminal and ground pin of nodeMCU to LED's Negative terminal as well as I uploaded blink ...
Sharifdeen Ashshak's user avatar
1 vote
0 answers
1k views

What is the recommended way to connect TP4056 charger module to NodeMCU v2

I want to power a NodeMCU v2 with a 3.7v 2000 mAh LiPo battery and charge the battery with the NodeMCU connected (i.e. under load). After looking into various forums, I ordered a TP4056 battery ...
Kannan Krish's user avatar
1 vote
0 answers
624 views

NodeMCU - Are all GND connctions born equal?

I'm designing a PCB which is based on NodeMCU board in its core. On NodeMCU there are some GND pins, most of them are to serve digital outputs/inputs, or external sensors which operate on 3.3V. Vin ...
Offer's user avatar
  • 25
1 vote
1 answer
863 views

PT100 sensor for measuring liquid resin, fully submerged

Edited Link to Pt100 sensor (That's the best i could do) https://www.intech.co.nz/products/temperature/mrh.html Link to ESP8266 datasheet http://www.handsontec.com/pdf_learn/esp8266-V10.pdf ...
Sanchit Agarwal's user avatar
1 vote
1 answer
3k views

AC 230V voltage line detection with Sharp PC814 switch (home automation)

I want to use home automation, so I am thinking of using an input to an ESP8266 from a PC814 bi-directional optocoupler for a 230 VAC mains physical switch. Using this scheme I don't have to modify my ...
Kalpesh's user avatar
  • 41
1 vote
0 answers
569 views

How to get NodeMCU to detect an external switch closure of an unknown voltage?

I'm getting really into home automation as a side project of mine and one of the next things I would love to automate is my doorbell. Short question: If I have a switch (momentary button in the form ...
John Greeny's user avatar
1 vote
1 answer
4k views

NodeMCU power via battery + battery charger + booster

I need to power a NodeMCU (as far as I know it can work with 3v3 but I use some I2C modules that need 5V so let's power everything with 5V.) I have a Li-ion battery (3.7V.) I have a TP5046 based ...
javirs's user avatar
  • 185
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0 answers
44 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
0 votes
0 answers
147 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
133 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
0 answers
562 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
0 answers
231 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
0 votes
1 answer
522 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
0 votes
0 answers
104 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
618 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
0 answers
90 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
40 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
27 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
0 answers
146 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
562 views

Providing power to NodeMCU (ESP 8266) from 5V output of an Arduino

Is it possible to power a NodeMCU from 5V output of an Arduino UNO board? I was trying to use the Vin of the NodeMCU as the input from the 5V port of the Arduino. It didn't work. Could anybody please ...
Abdullah Nasir's user avatar
0 votes
0 answers
168 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
1 answer
1k 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
0 votes
0 answers
38 views

NodeMCU http calls failing

I am trying to communicate between 2nodemcu v2, standalone everything works fine - webserver, api etc. but when I start communicating between both devices only first API hit works thereafter it ...
Varun's user avatar
  • 109
0 votes
0 answers
219 views

NodeMCU/ESP8266 to drive pulse sensor?

I have a Daikin BRP069A61, which is a heatpump accessory that allows the heatpump te smartgrid controlled. In simple terms: It will turn on when PV-power is available and will limit power to whatever ...
Rudy Broersma's user avatar
0 votes
1 answer
54 views

How to know the status of a two way switch through MCU

My project is this one that I asked earlier (except the fact that I'll be using SPDT switches) Two way lighting What I'm asking can the MCU detect if the circuit is closed (whether by the physical ...
coldbreeze16's user avatar
0 votes
1 answer
606 views

Cannot flash Wemos D1 using NodeMCU

I am trying to flash Wemos D1 mini (ESP8266) using NodeMCU according to this video. Pins NodeMCU → Wemos: RX → RX TX → TX D3 → D3 RST → RST 3.3V → 3.3V GND → GND EN → GND When flashing Wemos LED is ...
dma_k's user avatar
  • 101
0 votes
0 answers
257 views

How to wire MCU control signals with power and ground to control multiple external motors?

I'm working on a system based on a NodeMCU/ESP8266 WiFi controller, which controls two separate motor units, each consisting of a 12V motor and solenoid actuator. For practical reasons, I need to ...
DV82XL's user avatar
  • 101
0 votes
0 answers
113 views

getting delay in serial communication between arduino nano and nodemcu

I am making a project of transformer health monitoring in which I am taking sensor data from an Arduino Nano to a Nodemcu and then uploading to Ubidots server. The problem I am facing is that I am ...
Muhammed's user avatar
0 votes
0 answers
45 views

Turn on/Turn off circuit using one momentary button. Also, turn off the circuit using a command from NodeMCU

I have this 5v and 3.3v voltage regulator circuit using 12v input voltage. This voltage regulator circuit is used to powerup my NodeMCU and several sensors. Now, I'm having problems creating a circuit ...
forestvine's user avatar
0 votes
0 answers
139 views

NodeMCU AT Commands with UART not working

Hi, here are my specs :- PIC16F877A microcontroller NodeMCU (reflashed and got AT commands working via software only) XC8 Compiler (using MPLAB X IDE) Question :- What I'm trying to do is, trying to ...
RukshanJS's user avatar
  • 149
0 votes
0 answers
162 views

Turn Node MCU into a PLC which is integrated Lora module for IoT application

I've built a PLC that supports Lorawan and Modbus protocol using Node MCU. I managed to make it possible with Modbus by using OpenPLC. Everything worked well apart from its limitation in the distance ...
Thanh Nhon's user avatar
0 votes
1 answer
206 views

Issue with my solar charger using LM2596

I am using a 20W solar panel, maximum voltage 21V & maximum current 1.23 A. I am using LM2596 to dtep-down to 5V to charge my powerbank, hich will later power my Nodemcu (ESP8266 board.) Issue in ...
KAPIL KUMAR VERMA's user avatar
0 votes
1 answer
123 views

Direct contact to infrared receiver from microcontroller

I have posted this question also on arduino forum but can't get more answers there. So basically I have an old DVD player that has an IR (infra red) receiver and I would like to automate it with a ...
maris ancans's user avatar
0 votes
1 answer
152 views

ESP8266 Getting Unstable with the following circuit

When the resistors in this circuit are removed, the NodeMCU is working absolutley fine, however when these are put, ESP gets unstable and the relays are flickering. Also unable to flash with these ...
Suresh Kumar's user avatar
0 votes
0 answers
772 views

NodeMCU-12E - Conflict between I2C and SPI

I have SPI SD-card module connected to nodeMCU, and it's worked well. Next I try to connect I2C sensor, and it doesn't work. Looks like SPI conflicts with I2C, because when I disconnect SD-card, I2C ...
sharp's user avatar
  • 101
0 votes
0 answers
201 views

How to connect five flex sensors to on esp8266?

I’m using a lolin nodemcu 8266. I was wondering if it is possible to connect 5 flex sensors to one node (to make a glove which detects finger gestures). I’m an experienced programmer but new to ...
Kaizer Sozay's user avatar
0 votes
0 answers
55 views

Problem setting registers (SPI) [NodeMCU fw, nRF24L01+]

I can read registers somewhat fine, but when I try writing to a register in the nRF24L01+, it either crashes and I have to pull it out of the board, or the register becomes all 0s, and I can't reset ...
poorandunlucky's user avatar
0 votes
0 answers
74 views

Prevent spurious triggering of NodeMCU GPIOs

I designed a simple circuit to control a relay with a NodeMCU micro controller. The NodeMCU polls a remote web service via a simple API and pulls high or low the D1 GPIO according to what it's posted ...
Gianluca Ghettini's user avatar
0 votes
0 answers
60 views

Which pins need to be free to flash NodeMCU via USB

It is not completely clear to me, which pins need to be free (disconnected from other components) in order to flash the NodeMCU via USB with a firmware. Of course, this depends on the connected ...
Saren Tasciyan's user avatar