Questions tagged [esp8266]

The ESP8266 is a low-cost Wi-Fi chip/module with UART connections and a built-in TCP/IP stack.

135 questions with no upvoted or accepted answers
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2answers
415 views

How to localize cause of short circuit in proto board design?

I'm working on a basic application with a microcontroller controlling several components including a: 12V DC pump (Darlington array) 12V PWM fan (Darlington array) humidity sensor (I2C) and LED ...
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2answers
49 views

What happens if the load (connected to the output of the circuit) disconnects suddenly from Arduino/ESP32?

My circuit (that contains esp32 with few current and voltage sensor) is connected to 9Ah Battery (with BMS), where the load gets connected to see the discharge rate of the battery. There are times ...
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0answers
409 views

Solar charging a lipo battery with ESP8266 as a battery load

I am trying to add solar harvesting capability to my IoT device based on esp8266. I am using linear charge controller (MCP 73831) with solar input to charge a 500maH lipo battery. An observation when ...
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0answers
79 views

Have I got a dodgy batch of TMP36 sensors

I bought some TMP36 sensors from Amazon.co.uk for a small project (ESP8266 NodeMCU temp sensors) and have struggled to get sensible output from them I have tried reading them from A0 on the ESP8266 ...
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2answers
1k views

Explain why the NodeMCU auto-program circuit would be useful

I'm looking at the NodeMCU "auto-program" circuit but could not understand why it is there at all. From my point of view, this circuit enables open-collector outputs, but makes programming dependent ...
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0answers
4k views

ESP8266 Wake from deep sleep with an interrupt

I have an ESP8266, and a MCP23008 I2C GPIO expander. The GPIO expander has the ability to trigger an interrupt when a pin changes - this is handy, as it means we can do something when an input pin ...
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0answers
39 views

ESP8266 vs ESP32 and WakeUp vs Reset

Maybe it's my fault but I kinda dislike the design of the ESP8266 when it comes to wakeup from deep sleep via an interrupt. AFAIK (without an external circuit) the ESP8266 can not distinct between a ...
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1answer
45 views

Charging and discharging 18650 batteries with TP4056 modules via their power output terminals

I'm having those fancy ESP boards that come with a battery input pins/holders that can be connected to a battery to make them portable. They also have a dedicated USB port for charging/sketch uploads. ...
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0answers
73 views

12 V PWM fan and Wemos D1 Mini - ground loop?

Newbie here. I'm trying to power a 12 V 4-wire fan and a Wemos D1 Mini from the same power source. The aim is to use a Dallas DS18B20 temp sensor and increase/decrease the fan speed as per the temp ...
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0answers
73 views

Flaky GPIO on ESP8266, how do I solve it?

I have an ESP8266 where I took one of the GPIO pins, configured the pullup on the input, then connected it to one lead of a 15m cable and the other lead to the ESP8266 ground. The problem I have is ...
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0answers
62 views

What would be needed to read USB keyboard input on the 8266 or ESP32 chip?

My objective is to read input from a Keyboard Wedge device (i.e. Hand Scanner) which will emulate a keyboard entry and a carriage return and then broadcast that information to the cloud. I think I ...
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125 views

Proper capacitors for ESP8266-12F?, resetting at high current peak

When using the ESP8266-12F on a PCB I designed myself it keeps resetting after a high current spike of another module (Sim800L). I ofcourse tried to solve this using capacitors but I seem to have made ...
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0answers
28 views

Is Wemos D1 R2 compatible with micro python?

I wonder if Wemos D1 R2 ESP8266EX compatible with MicroPython and editable using uPyCraft. If so please say so.
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1answer
75 views

What is the major difference between a WiFi and RF Module?

In an interview recently, someone asked me what is the major hardware level difference between a WiFi module (ESP8266) and RF module (nRF24L01+) that I had used in my projects. I mentioned that both ...
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2answers
151 views

SK6812 - LED Flickering

I am facing a strange issue while building a simple LED matrix. I am using the SK6812 LEDs and an ESP8266 controller. The LEDS will be controlled over Wifi. My matrix contains about 180 LEDs on a PCB ...
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1answer
92 views

Modify Transformerless Power Supplies

Based on this article: https://hackaday.com/2017/04/04/the-shocking-truth-about-transformerless-power-supplies/ I have some rf wireless plug outless which use transformerless power supply. I would ...
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0answers
224 views

WS2812b LEDs intermittently do not respond to data signal

I have wired up permanent holiday LEDs on the front of my home, using a 5V 60A power supply and several strips of WS2812b's (generic Neopixels), controlled by a Wemos D1 mini. The Wemos is powered ...
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0answers
52 views

nRF52 Bootloader over ESP12E

I'm using nRF52 DK with 14.2.0 SDK. I created a LED blink project for testing and extract its HEX file. I uploaded the program to the nRF52 over USB (J-Link-Keil IDE) and the HEX file over ESP12E (SWD)...
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1answer
187 views

Why does making this change to my DHT11 code cause it not to work?

Note: This might not be a programming question. If it turns out that it is, I will close it. I am using an ESP8266 to build some air quality web servers. One of the sensors I am using is the DHT11 (...
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1answer
2k views

4-pin PC Fan PWM control and speed monitoring

I want to control and monitor the speed of a 4-pin PC fan using an esp8266. When there is no PWM control signal sent to the fan from the esp this code reports the fan speed correctly. However, ...
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0answers
228 views

esp32 resets when relay switches from ON state to OFF state

When I switch a 12v relay from ON to OFF using esp32 then the ESP is restarted. Also it happens only when there is an AC load. I control 12V relay with a transistor. This is my relay How to solve ...
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1answer
151 views

LED display flickering when connected to an ESP8266

I'm building a simple clock using an ESP8266 chip and a 7 segment LED display which is driven by a HT16K33 chip. The ESP8266 uses 3.3V, the display can handle 5V. I want to use a simple USB cable as a ...
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69 views

Control servo with 4 wires with Blynk

im a beginner in coding and I was wondering if I could control an old servo using the Blynk app. I want to control the direction, so it can unroll the screen up and down. We opened the servo to look ...
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341 views

Controlling Wemos D1 power with N-Channel MOSFET

I am trying to implement something similar to this: https://youtu.be/nbMfb0dIvYc?t=4m27s Basically, the idea is that the microcontroller (a Wemos D1 Mini in my case) is powered up by an external ...
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2answers
269 views

Powering a NodeMCU 0.9 ESP 15

I am fairly new to electronics, and I got a NodeMCU 0.9 ESP-12 for my IOT Projects. I want to power it through the wall, and I have an adapter which outputs ...
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350 views

PMS5003 ST - Humidity / Fog - modelling

I am building a simple PM2.5 PM10 station based on PMS5003ST (Plantower) and ESP32 to measure the particles in the air and convert the readings to the Air Quality Index. Everything works fine, but i ...
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0answers
187 views

Audio op amps - what do they do to the audio I hear from the speaker?

I have a simple DC circuit which outputs audio from a ESP8266 attached via 2 wires and a NPN transistor to a simple speaker. It uses this library : https://github.com/earlephilhower/ESP8266Audio/ to ...
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0answers
333 views

ESP-01 module drawing 3mA on Deep Sleep

I'm trying to use the Deep Sleep feature of the ESP8266 with an inexpensive ESP-01 module. These need to be modified to bridge GPIO16 to RST, in order to wake up from deep sleep. Also, I have removed ...
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2k views

Light Strip with ESP8266 and ZigBee for HUE Bridge

I currently have an ESP8266, which controlls my WS2812b light strip. I want to add it to my current Hue setup(1 Bridge, 4 Lamps). I know that I'll need a ZigBee module of some sort. Are there any I ...
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0answers
346 views

ATMEGA328/ESP8266 communication works ~80% of the time

I have ATMEGA328 connnected to ESP8266 via UART. All I'm trying to do is simply send a constant value over WIFI to a simple TCP server. This is the blueprint of UART commands sent by ATMEGA328 (full ...
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0answers
356 views

How to protect MCU IO and 5V from shorted +12V

I would like to protect an MCU from 12V being shorted either to IO or it's 5V supply. This is very similar to the question asked by kamil here: How to protect microcontroller board 1-wire from ...
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0answers
231 views

Converting a long low pulse to a short low pulse to wake up an ESP-12F

I'm trying to wake up an ESP-12F from deep sleep mode by pulling the RST pin low for a brief moment (~10ms or less). I thought I needed a monostable (one shot) circuit so I bought an LMC555 timer to ...
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0answers
129 views

Bell button as input

I got a simple bell system from elcom. It works with 12V AC. When I measure the voltage at the switch it is 1V when not pressed. When I measure the switch sides to the power input of the bell system ...
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0answers
244 views

What is the meaning of the second value in the ESP8266 bootloader output?

When connecting an esp8266 to a serial port at 74880 to flash or inspect it, depending on what pins are held down there are a series of diagnostic boot messages. The line looks something like this: <...
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297 views

power supply noise causing resets of MAX7219 LED driver

I have wired up an ESP8266 wifi uC to a MAX7219 7-segment driver. The setup works well, except that the circuit seems susceptible to external noise. The main issue I have noticed is that activating a ...
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2answers
631 views

ESP8266 detect LED flash with photoresistor Schmitt trigger?

I made some experiments with ESP8266 to detect when an external LED is on or off (I need to log this activity). This is the test-circuit I used till now: simulate this circuit – Schematic ...
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0answers
2k views

AMS1117 3.3V overheating

I have a LED strip and an ESP8266-12 to control it. As the LEDs need 5V I'm using an AMS1117 3.3V linear regulator to get the 3.3V needed for the ESP8266. The circuit works fine but when I try to ...
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0answers
576 views

ESP8266 and ATmega328 UART communication, gets() function

I'm trying to get an ATmega328 and an ESP8266 to talk to each other over UART. In the attached minimal example, I have an LED on pin 16 (B2) that should start on and do a slow blink to show data was ...
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0answers
960 views

What does Unvarnished Transmission Mode Mean?

I am using an ESP8266 Wifi Module and I have come across a command "AT+CIPMODE=X" which basically sets the mode of the wifi to normal mode if X=0 and Unvarnished Transmission mode when X = 1. I have ...
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230 views

ESP8266 servo controler

I am building a small application, that should be able to connect over wifi to server, pull some data and turn a connected servo accord the result. The system should be powered on battery. Is this ...
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0answers
557 views

Esp8266 and uln2003 restarts

I am trying to drive 6 LEDs from an Esp8266 (esp201 break out board). Because of the Limit current of 12 mA the esp can do i want to use a 7way darlington Array to Power the LEDs. I have programmed ...
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0answers
7 views

Powering mixed 5V and 3.3V circuit from AA batteries

This my first more-serious project :) I want to integrate a 5V (air dust) sensor with my ESP8266 IoT gizmo running on 3.3V (we can call it a DIY weather station). I've bought a sensor with Vin spec ...
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0answers
17 views

How does the external antenna in ESP 8266 modules work?

I want to test the downloading and uploading speeds from various antennas of my choice via an ESP8266 microcontroller. I came across this design which I was planning on using for this. This would be ...
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1answer
48 views

Floating analog input value

To use my sensor I need to supply 24V. So I converted 4.5 V from battery pack to 24V and converted it again to 0-1.66V using a voltage divider. So far I can read the output of the sensor using the ...
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0answers
14 views

Nodemcu controlling a button on a pcb?

So i am trying to connect this button with a Nodemcu esp8266 (the push button on the bottom side of the pcb in the picture) Can anyone help me to wire this to a esp8266? Also i measure 3.3v whether ...
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1answer
48 views

How to select external components for LM2596-3.3V?

I want to power an ESP8266-12F with a 12V power supply. The 12V power supply is also used to power a led strip. I need to step down the 12V to 3.3V. The maximum load is 1A. I found the LM2596-3.3V to ...
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23 views

How to power multiple Wemos D1 Mini

I’m planning on making my bay window blinds tilt automatically with Alexa. I've done plenty of research but can’t find my answers, hence the question. I have 4 individuals blinds which all need ...
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0answers
54 views

Is it necessary to opto-isolate a darlington array output?

I've got the following circuit going: A Vishay opto-isolator (CNY74-4) that takes input from buttons that work on 24V, and outputs to microcontroller pins (an Olimex ESP32-PoE-ISO in my case). A ...
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2answers
35 views

HX711 and 3 load cells

I am doing a small project with ESP32 and HX711 and I need to have 3 load cells. Like this one: I am totally newbie in electronics, my ground is programming. What I found are projects with 1, 2 or ...
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23 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 ...