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Questions tagged [esp8266]

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

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4k views

Using TP4056 module to charge battery while load remains connected

I need a circuit that utilizes the tp4056 breakout board to power a NodeMCU ESP like so: tp4056 USB port connected: 18650 battery charging and NodeMCU running of USB tp4056 USB port not connected: ...
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2answers
464 views

How to 'de-mux' a tri-state pin?

I would like to use a single pin (tri-state buffer, 3.3V logic in case this matters) to drive two P-channel MOSFETs as high-side switches. Only one of them will be 'on' at any time. When the pin is in ...
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1answer
545 views

I need a switch that not only detects open/close, but also sends a pulse to wake up an ESP8266 whenever the (debounced) state changes

My application is that I'm trying to create a very small, "button battery" powered device to sense the opening and closing of a switch and send state changes via WiFi to another device on the network. ...
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1answer
15k views

Power Wemos D1 mini from battery

I have (a chinese clone of) a Wemos D1 mini board, which uses the ESP8266 microprocessor. Since the ESP8266 has a 3.3V operating voltage, it includes a low dropout regulator for the USB 5V. According ...
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2answers
730 views

Why relay module occasionally switches by itself ON?

I am using this common relay module from Ebay (image below). It works very well 99.9% of time. It's controlled by ESP8266. It's in the plastic box with some AC wires (which are obviously plugged in ...
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2answers
2k views

5V to 3.3V logic level converter

I am trying to connect an ESP8266 module to an Arduino. Giving the fact that ESP8266 runs at 3.3V and the Arduino at 5V i need a logic level converter from 5V to 3V3. Is there a way i can build one ...
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3answers
505 views

Driving relay with ESP8266

I am doing a circuit to drive a 5V 70Ohms relay using ESP8266. The max GPIO source current of ESP8266 is 12mA. I got this information from the forum here https://bbs.espressif.com/viewtopic.php?t=139#...
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2answers
8k views

ESP8266 driving relay and reading button

I want to have an ESP8266 (ESP-01S), which has only GPIO0 and GPIO2 exposed, drive a relay (via an NPN Transistor on GPIO2) and read a button (GPIO0). The circuit diagram is as follows: The problem ...
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1answer
6k views

ESP8266 eLUA (NodeMCU) vs MicroPython

I am searching for an unbiased, up-to-date comparison of the eLUA (NodeMCU) and MicroPython on ESP8266. I can only find very superficial reports/blogs of users trying out one or the other. - All of ...
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4answers
4k views

How can I turn off a 3.3V circuit with a 3.3V microcontroller

I'm working with ATTiny85 that has low current (40 mA) GPIO. In the other side I have a power supply (battery with ~5V) connected to a LM317 and an ESP8266 that demands high current (more than the ...
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2answers
8k views

MOSFET switch using an optocoupler

With the parts in the mail, haven't had the time to test, but the simple question: will this work, or what improvements are needed? What it's supposed to do: a MOSFET switch for 12V, 0.5-3A loads, ...
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3answers
16k views

Is it safe to use ESP8266 with 3.7V?

I am using an ESP8266 WiFi module in a circuit. The battery is 3.7V. Is it safe to give the ESP8266 (3.3V) directly without a voltage regulator?
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2answers
2k views

Latching Relay Driver

I've selected a potential latching relay for use in a project (switching mains power), but - having been away from electronics for a while - I'm still trying to wrap my head around a couple things. ...
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4answers
5k views

converting 3.3v to 1.2v

I have a electrical problem that I hope to get some help with. Let me first start of by saying that I'm quite a noob in this field (I'm a IT guy), but I hope to learn something. The problem I have is ...
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3answers
11k views

Safely pull 5V to GND on 3.3V GPIO

I want to control an 5V relay board with an ESP8266 (which operates on 3.3V). Schematic of the board: IN2 is normally on 5V and must be pulled to 0V for enabling the relay. I saw people using an NPN ...
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2answers
815 views

Multiple buttons connected to reset pin

I'm building a battery powered device based on ESP8266. There are few buttons (lets say 4 at the moment). After pushing any of them ESP should perform some action ...
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1answer
347 views

Controlling Wemos D1 power with P-Channel MOSFET

[ Note: this is the continuation of another question, the first one being my attempt to implement the same idea using an N-channel MOSFET. Based on the answers I received there, I went out, bought a P-...
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2answers
124 views

Circuit to turn microcontroller on when reed switch state changes (to monitor door lock state)

I'd like to build a circuit that provides power to a microcontroller (ESP8266 in this instance) when a reed switch is changed from closed to open AND when changed from open to closed. This is to be ...
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1answer
2k views

ESP Breakout PCB design (KiCad) questions

My first PCB made with KiCad. I have some specific questions about my design. First I was not sure of this would have been another down-vote magnet but this article encouraged me to post this. ...
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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
379 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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1answer
300 views

button which wakes up the esp8266 from deep sleep, but can be used as common button

The goal is to have a button which wakes up the esp8266 from deep sleep, but can be used as common button while the code is running. This is a follow up of an unsolved Arduino SE question. esp8266 ...
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0answers
338 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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1answer
170 views

nodemcu/esp8266 reads lower than expected on A0

I got a NodeMCU/ESP8266 development board and am trying to utilise the A0 (10-bit ADC) input to read the voltage from a voltage divider on the 3.3V pin. So I have the following: simulate this circuit ...
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1answer
2k views

Transparent Wi-Fi module with RMII input

I need to convert a Ethernet-connected embedded project with wireless connection. I'm looking for a low-cost (main constraint, less than USD $15) and most open-source/-hardware possible Wi-Fi bridge ...
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2answers
270 views

Multipurpose momentary button - microcontroller/arduino/esp8266

as more of a hobbyist than a pro I apologise if I'm asking the wrong questions, however I have been researching for a while and hoped Stack exchange might help. I've read a few articles on low power ...
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0answers
237 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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1answer
54 views

how to use an npn as a switch between battery and motor?

I am a noob playing around with nodemcu and esp8266. I am trying to control a motor in an automated air freshener. I had been trying to power the motor with board supply but I gave that idea up when I ...
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2answers
73 views

ESP8266 GPIO2 - invert logic NPN transisotr

I make big mistake in my design. I connect output to ESP8266 GPIO2 at this pin I got base of NPN transistor to control LED. I test it on breadboard but probably by noise or "universe magic floating ...
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3answers
62 views

How should I drive a chip where I need to pull pins low in order to enable

I am wanting to use a FSTD16211 in my circuit. It's datasheet says that pins OE1 and OE2 should be high to disconnect the 2 channels of the bus, and both should be low to connect the 2 channels of the ...
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2answers
93 views

Using a LED with an ESP8266 module

I'm building a project that uses a high power LED (3 Watt) in connection with an ESP8266 module using the module as an access point and connecting to it with my smarthpone. I've successfully managed ...
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1answer
323 views

Putting an ESP8266 to sleep via either of two signals

I've got a circuit which I'm hoping to use to shut down my ESP, except where an interrupt happens from an external chip (MCP23008 GPIO expander), or I have chosen to manually keep myself enabled. ...
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2answers
703 views

For an Arduino and ESP8266, can I power up the ESP8266 from a set of 2n2222 transistors?

I am trying to power-on my ESP82666 and it draws about 300ma on a 3.3v. Can I power it up just like this, but instead put some sort of 2n2222 in place of the other transistors? BTW: I am new to ...
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1answer
851 views

SSR LED light on even when ESP8266 pin is off

I'm powering a heater with an SSR and esp8266 nodemcu module. I've found out that I need a higher voltage to effectively trigger it than what the nodemcu can put out on a digital pin (from previous ...
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2answers
2k views

SSR ticking when controlling heater

Trying to control a 220v electric convection panel heater with a Fotek SSR (SSR-50DA http://akizukidenshi.com/download/ds/fotek/fotek_ssr.pdf) which is controlled by an nodemcu esp8266 (arduino). It ...
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3answers
435 views

Can't connect ESP8266 to Raspberry serial

I have been trying to get ESP8266 WIFI module (ESP-12E) to connect to Raspberry PI 3 serial port, but I've tried everything I could think of, but still can't get it to connect. Connection I have ...
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1answer
797 views

Electrical noise resets & chattering in relay modules using ESP8266

I am trying to build my own SONOFF like device by using a Wemos D1 mini and associated circuitry. I am facing an issue with electrical noise where whenever switching of the relay causes chattering ...
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1answer
1k views

DHT22 needs electrical reset?

Context : Building a wireless sensor based on ESP8266 + DHT22 (+ "X-8266" board) + DHTtester example progam I fell on a rather strange and annoying problem : Problem : When powering up the board ...
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1answer
9k views

How to drive a relay from ESP8266 gpio

I'm trying to connect an ESP8266 gpio to one of the relay modules (please check the image). As I understand with a very basic background, ESP should be able to trigger this relay modules since all ...