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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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Making a wireless lavalier microphone with ESP8266-07

I'd like to make a lavailer microphone and receiver using two ESP8266-07 Wifi modules. I'm using a condenser microphone with it's own preamlifier using 5V. I want to compare my signal with 300kHz ...
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1answer
19 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
23 views

Electrical noise on wemos D1 mini

There is electrical humming sound coming from wemos D1 mini v2 module. I'm using 5v 3A power supply connected to 5v input pin. I suspect its the current input which cause sparking/humming sound. ...
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1answer
13 views

Esp8226 with opto mosfet switch LBA110

I want to switch AC load by LBA110 because it has NC switch pole and tiny side. I tried to read datasheet, but with my bad knowledge about electric, I can not find out how to make it work. Is it work ...
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38 views

Backup power supply using capacitors to help esp8266 run for 3-4 seconds after power failure [on hold]

I need to make a circuit with introduction of capacitors in parallel with input supply of esp8266(3.3Vdc) to run it extra 3-4 secs after power failure, Is it possible to gain extra 3-4 secs just ...
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1answer
49 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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1answer
46 views

Need LM324N non-standard logic converter

I have a background in electronics but am very rusty and need a circuit to monitor my security system. I would like to monitor the voltages at my security system board for each of the door contacts, ...
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28 views

How to calculate R1 and R2,? How do Mosfet IRF540 and ESP work in the circuit

So the 3.3V PWM signal from ESP is sent through R2 to the Gate to breakthourgh the Vgs(th) to make Mosfet ON, and the author of the circuit say Gate is pulled high to 12V by R1. But I don't understand ...
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31 views

Does ESP8266 deep sleep make sense while on the power supply?

If ESP8266 is powered via a dedicated power supply 220V AC → 3.3V DC. Is it worth it to put ESP to deep sleep in order to reduce power consumption? For example the indoor weather station, which ...
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1answer
29 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. ...
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16 views

ESP8266 Web Server Restrict Access

I have checked the following project and similar other webservers. https://randomnerdtutorials.com/esp8266-web-server/ My main issue with this code is that there is no way to restrict where can ...
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17 views

esp-12 power supply + backup by 4F capacitor 5.5v + ME2149, is it working?

I made my own energy meter using esp-12, I need to save data to esp spiffs when loss grid power, In this case, I do not need wifi than esp turn to modem-sleep mode, so working current is about 20 - ...
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11 views

lilypad wifi and bluetooth together [closed]

I would like to use both wifi and Bluetooth with LilyPad, is It Possible? Background: I wanna build a Suit with lilypad and a bunch of sensors built-in it and and the board has to have Internet ...
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39 views

Programming ESP32 Microcontroller with FTDI's FT231XS USB Chip

Purchased FTDI's FT231XS from DigiKey I can see data from the ESP32 microcontroller but when I try to write to it, esptool just says connecting and nothing happens. I can use a usb to serial cable to ...
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1answer
38 views

The simplest “adaptive” downward level shift solution?

I want to build a level shifter circuit for the RX pin of my ESP-12S. The goal is to convert any level between 3.3V and 5V to 3.3V as I might use many USB to UART breakout boards with different output ...
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2answers
37 views

Voltage drop after writing to slave register with I2C protocol

I'm trying to control this bipolar stepper motor with an Adafruit Huzzah32 (ESP32) board and a stepper driver shield. Power sources: ESP32: 5V USB port Shield: 4 AA-batteries in series I ...
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2answers
65 views

ESP32 powered by supercapacitors

It's been ages since I had to design something electrical so please don't laugh if this is stupid idea but I would like to power ESP32 with super capacitors, just for 30 sec or so so it can finish the ...
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15 views

ESP32: Using SENSOR_VP as GPIO

According to the ESP32 Hardware Design Guidelines, in section 2.1.6, they said: If SENSOR_VP and SENSOR_VN are used as GPIOs, while ADC is supported by other pins in the circuit design, users ...
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1answer
62 views

Switch AC contactor with an ESP-12s - will this circuit work?

I'm trying to make an ESP-12s control 2 relays to switch an AC contactor. I made this schematic in Altium and posted to ask if it will work. The 2 DC power supplies (3.3V and 5V) are isolated.
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14 views

Naming confusion, how to connect DAC (BB/TI PCM1603KY) I2S, which pins do I need to use?

I am totally new in the field of DAC's and I2S. I salvaged this board from a DVD player and is well documented. There are three data lines DATA1..DATA3 that will be used for ...
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1answer
39 views

Pullup resistor operation between the ESP32 and a Bus MCU

I have an ESP32 as my main controller and a Bus. The bus operates where Pins 55 & 56 needs to be HIGH in order for the bus to be OFF. My ESP will drive the bus by enabling it by pulling those ...
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1answer
953 views

Do I really need diodes to receive MIDI?

All the schematics above use a diode before the receiving pin on the optocouplers. The problem was, I never able to find the exact same diode as the schematics. Before, I'm using H11L1, but it never ...
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1answer
55 views

esp32 3.3v relay

I am developing my first PCB and I would like to know how best to power a 3.3v relay with control from ESP32 module. Because I am powering the relay with 3.3v do i even need the optoisolator in my ...
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1answer
24 views

1S or 2S li-ion battery charging design for ESP32/Nextion device

I am designing a portable battery powered device and trying to decide on my battery configuration. It will use an ESP32 chip with a few additional ICs, which will draw about as much current as an ...
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2answers
78 views

pH sensor box - ADS1115

I made a pH sensor box to monitoring my hydroponic culture. I built a PH sensor box (see Frtitzing) to use for my hydroponics system with: - Esp8266 - ADS1115 - BNC + pH probe (2X) Unfortunately the ...
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75 views

What is the most sane way to switch between 5v and 3.3v on a PCB on the same lines?

I apologize for the blasphemy I may spit during this question, I am a newbie in electronics. That said, I want to design a PCB that will house an ESP8266, the chip I selected provides both 5v and 3....
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1answer
58 views

ESP8266 ESP-01 only responds “Recv x bytes” after an HTTPS request

I'm using ESP8266 ESP-01 for wifi data transfer. When I send the request for 80 server's port, the data is successfully returned. REQ: ...
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1answer
41 views

Can I use this garage door circuit to power an ESP8266 [closed]

So this circuit is from my garage door opener. Basically it has 24VDC coming into it which runs directly back to the motor unit of the garage door opener. My limited understanding says that there is ...
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2answers
67 views

Can a 74HC595 independently enable or disable output pin without interrupting other active pins?

I am doing a project for which I need to expand the IO pins available on NodeMCU. I plan to use 74HC595 for the same, I have a question regarding that as given below. Is it possible to independently ...
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0answers
24 views

atmega128 doesnt return from function even if Extended.M103 fuse bit is disabled

Hi I know i should n't be using atmega128 but it will take some time to replace besides there are 100's of PCB already in making. my problem is, if you look at the main() i have declared each function ...
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1answer
77 views

I want to create a stable 0-10 V DC output from a 3.3V PWM signal (arduino/esp8266)

I want to control an EC motor, but I have some difficulties with the motor's control input. According to my measurements it has a ~50kOhm input impedance, and probably also has an (unknown) RC low-...
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2answers
112 views

Measuring 0-240v 50-60hz Mains AC with Arduino/MCU

What is the proper way to measure 0-240v 50-60hz Mains AC with an arduino / 3.3v mcu? (Edited to include a diagram of a proof on concept, which is transformerless) Can anyone confirm that this is ...
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1answer
56 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
109 views

Why use UART to communicate between Arduino and ESP Wi-Fi module?

I have been learning about the different communication protocols used between Arduino and other components/sensors, namely, SPI, UART and I2C. I want to add Wi-Fi to my Arduino UNO project using ...
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1answer
42 views

ESP8266 circuit with an LED

I'm building a project where I use an ESP8266 module to control a LED with my smartphone. For my project I want to battery power the ESP8266 and the LED so I'm using two Lithium Ion batteries. I've ...
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2answers
71 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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3answers
53 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
117 views

Why use a series resistor between Arduino RX and ESP8266 TX?

I have seen this in several schematics which i assume are professional since they are for popular open-source products. But i can't figure out why there is a 470 Ohms resistor in series between the ...
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2answers
92 views

LED driven by MOSFET is dim

I have this schematic: I had to replace T1 transistor with a MOSFET (because D4 on an ESP8266 has to be high at boot time and the transistor reduces the pin voltage, so the ESP doesn't boot - see my ...
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3answers
91 views

eagle schematic check [closed]

I will do basic IOT project with esp-wroom-32. but I am machanical student. I need to help please check my design. my component: - esp-wroom-32 - button - pad-resistor - locig level converter - ...
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2answers
58 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, and use the Silicon Labs CP210x, and I have had NO luck at all with ...
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2answers
36 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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42 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 ...
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0answers
29 views

ESP-01 deep-sleep wake up button that can also detect long press

I'm designing an IoT smart button to turn on or off a light with an ESP-01. I want it to run off a battery so I'm using deep-sleep. The problem is I only want to have one button that you could press ...
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1answer
47 views

28V Stepdown with TracoPower TRN 1-2411 DC/DC converter for ESP8266?

Im new to electrical engineering. For a project I want to supply an ESP8266 with power by using a 28V Milwaukee Battery. My Question is: Can i supply the esp at the VIN PIN using the 2411?
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2answers
45 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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3answers
46 views

Strange LED flicker when powered via buck converter

I have a 12V supply with a buck converter stepping down 12V -> 3.3V to power an esp8266 microprocessor. The esp is controlling a 12V LED strip switched via 2n2222 transistors. When all LEDs are ...
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2answers
98 views

Help needed in understanding MOSFET datasheet

I am trying to find a logic level MOSFET for 3.3V operation. In my case, I am trying to compare AOD510 & AO4402. AOD510: \$\mathrm{R_{DS(on)}}\$ @ 4.5 \$\mathrm{V_{GS}}\$ = 0.004 ohm but has no ...
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0answers
38 views

Controlling LED strip with Wemos D1 mini

I have a 12v led strip and have tested the current draw at ~500mA per colour. I want to drive this via my Wemos GPIOs which are 3.3V @ 12mA max. For testing I have been using 2N2222 transistors with ...
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1answer
58 views

74HC589 - stock lead times are high, looking for alternative parallel to SPI tri-state chip for ESP8266

My prototype was going to use 74HC589 as a parallel to SPI interface for ESP8266-07 MCU. They are in short supply for quick delivery at the moment. I am asking for suggestions for a similar chip ...