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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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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 ...
0 votes
2 answers
159 views

Can't power controller and LEDs with chosen power supply (works in one project but not in other)

I'm currently running into a rather confusing problem... I'm trying to power a strip of 60 WS2812 Leds and an NodeMcu/ESP8266 board. The supply I chose is a 5V/4A supply. This one to be precise: ...
0 votes
1 answer
164 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 ...
2 votes
3 answers
2k views

Resetting of NodeMCU ESP8266 in deep sleep

I have been doing a project as my first project to learn ESP8266 applications. My project is a temperature and humidity values data logger and upload the data to Thingspeak. The sensor used is DHT11. ...
0 votes
0 answers
38 views

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....
1 vote
3 answers
381 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 ...
0 votes
1 answer
178 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 ...
-1 votes
1 answer
58 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 ...
0 votes
1 answer
212 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 ...
5 votes
1 answer
4k views

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 ...
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 ...
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 ...
0 votes
1 answer
235 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 ...
2 votes
1 answer
926 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 ...
0 votes
1 answer
374 views

Powering NodeMCU

I am trying to power a NODEMCU board using a battery. I am using a TLV713P to regulate the voltage. Can I power a nodeMCU ESP32 board using this regulated voltage by giving it to the 3V3 pin?
-1 votes
1 answer
727 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 ...
0 votes
1 answer
2k views

MCP23017 with NODEMCU v3 (lolin) I2C doesn't work

I want to use NodeMCU v3 with a MCP23017 that has a MAX6675 at the end. Everything is in the circuit; please see the image. The MAX6675 (U3) doesn't want to work with the MCP23017. First MAX6675 (U4) ...
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 ...
1 vote
1 answer
748 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 ...
0 votes
0 answers
54 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 ...
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 <...
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 ...
0 votes
0 answers
37 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 ...
1 vote
0 answers
148 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 ...
0 votes
1 answer
138 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. ...
0 votes
1 answer
219 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 ...
2 votes
3 answers
65 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 ...
1 vote
1 answer
882 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 <...
0 votes
0 answers
56 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 ...
7 votes
7 answers
3k views

Trying to get (more) accurate readings from thermistor (electronics, math, and code inside)

So I'm trying to get accurate temperature readings off this TDK B57164K472J thermistor... It's connected in series with a 1 K resistor, and connected to an ESP8266's onboard ADC. The thermistor has a ...
2 votes
1 answer
243 views

Controlling servo with MOSFET [duplicate]

I'm trying to understand how to drive a servo that needs 5 V power with a 3.3 V output microcontroller. If I have a 3.3 V PWM signal and a 5 V power source, is there a way that I can use a single N-...
2 votes
4 answers
3k views

TPL5110 doesn't work with NodeMCU

I am using a TPL5110 timer to drive my NodeMCU, in order to keep battery consumption low, but I can't let it work. I have setup the standard circuit for this timer, as below: Whenever I apply power ...
0 votes
1 answer
114 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 ...
1 vote
3 answers
3k views

Remove ESP8266 from NodeMCU board

I want a simple programming jig for the ESP8266. Sadly, all of the jigs I can find on eBay and other sites have not worked for me. I use the Silicon Labs CP210x, and I have had NO luck at all with ...
1 vote
2 answers
322 views

How to get a constant 5 V power supply when using the same power supply for motors and micro controllers

I have made a WiFi controlled car using NodeMCU. It works fine if I connect the NodeMCU to a separate 5 V supply. If I use the same power supply for both the motors and the NodeMCU, it resets ...
1 vote
2 answers
1k views

SIM800C GSM module works via PC but not on battery

Before giving the specifications of my project, I'd like to say that I'm a total beginner in electronics but I do have a background in IT development. I also want to apologize if this question has ...
0 votes
0 answers
192 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, ...
0 votes
2 answers
280 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 ...
0 votes
0 answers
838 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: ...
0 votes
1 answer
80 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 ...
0 votes
0 answers
350 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 ...
3 votes
2 answers
742 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 ...
1 vote
1 answer
1k views

I'm getting an error while uploading my code to an ESP8266 via an Arduino

...
3 votes
3 answers
17k views

ESP32 using acs712 give wrong values

I'm trying to measure current with acs712 30A current sensor connecting to NodeMCU-32S but I'm getting wrong and unstable values. For zero current the ADC pin should read value of 2048 (esp has 12 bit ...
0 votes
1 answer
623 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 ...
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.
1 vote
1 answer
300 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 ...
1 vote
2 answers
174 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 ...
1 vote
0 answers
54 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 ...
0 votes
1 answer
126 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 ...