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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26 views

Is it possible using two 3.3v LDO from one SMPS AC-DC 5V to power 2 MCU?

I'm planning use two LDO 3.3V to supply power for two MCU, one is STM32, one is ESP-12. Input power of these two LDO come from one SMPS module 5v 3W (HLK-PM01). The reason is I'm using STM32's ADC and ...
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23 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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28 views

esp8266 reset - power consumption

I am working on project with esp8266 UC powered with 3.7v lithium ion battery, where the reset pin is pulled low to keep it OFF. I would like to know if my battery were to be consumed with this ...
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30 views

WRL-1368 (ESP8266) wifi module briefly flashes blue LED once when powered up, then nothing happens

I bought a WRL-13678 wifi module, but when I connect it to a 3.3V power source, the blue LED flashes once, then nothing happens. I tried powering it from a 3.3V breadboard power supply (connected to ...
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39 views

Low power RF switch [closed]

Sorry about my noobie question but here it goes: I am trying to control the rainbird 9V latching solenoid valves on my garden with arduino and esp8266 but the catch is, there is no electricity where I ...
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43 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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19 views

Configure ESP8266 as access point so can receive strings from my phone

I am trying to establish communication between my phone and an ESP8266 (one way) without the mitigation of another access point (router). The ESP8266 should host a WiFi network (access point) and the ...
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3answers
138 views

How can I trickle charge NiMH batteries as part of an IOT controller?

I have built an IOT motor controller board that's powered by 4 AA NiMH batteries in series. I want to use a solar panel to trickle charge the batteries, but the voltage slowly decreases even when the ...
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1answer
61 views

Why is JSN giving error readings when powered with Buck converter 12v to 5v different power source?

When I power my esp32 with an USB cable and check the readings of JSN-SR04 it shows correct and consistent readings. But when I connect esp32 and jsn with 5v from LM2596 12V input errors are not ...
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67 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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151 views

Is it possible to figure out how many times a mcu is programmed?

Wondering how many times I upload a new binary to a microcontroller, while developing I do this very often. Is there an upload counter somewhere inside the microcontroller or is there another way to ...
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16 views

Same software on single ESP-12f slower than on NodeMCU

I have programmed a small software to control an LED strip using an esp. I've written a web app which sends a request to the esp which then applies the color. So far everything works, but I've got a ...
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25 views

ESP-WROOM-32: Timed out waiting for packet header

I just got back my custom PCB using the ESP-WROOM32 module. I'm using an FTDI with it. GPIO0 is connected to ground via a jumper. I made a very stupid mistake and forgot to include a pushbutton and ...
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1answer
29 views

DHT22 doesn't transmit to NodeMCU V0.9

I am developing for the NodeMCU V0.9 with the NonOS SDK and can't get it to communicate to a DHT22 sensor. Wiring: 3.3V on NodeMCU -> + on DHT22, Ground to - and pin D1 to signal, there is a 6.8k ...
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73 views

Whats the purpose of 0R in Sonoff POW [duplicate]

I'm designing my own Sonoff with ESP32, with power monitoring capability. Now before I start my own design, I took a look at Sonoff design. In the Sonoff POW the power metering IC has a 0R resistor, ...
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84 views

MOSFET not giving out full 12V

I'm using three IRLB8721 MOSFETs to power my LED strip. Through an ESP-12F I'm delivering 3.3V to each gate, which should bring me a 12V output, I think. But this doesn't work, I only get 5.8V - 7.6V (...
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35 views

What is single and multi connection mode( AT+CIPMUX=0 or 1) in esp8266 AT commands

I was studying the AT commands to program atmega328p for the communication with esp8266. Now I am confused with the command AT+CIPMUX=0 or 1 , it explains that 1 for multiple connection, 0 for single ...
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42 views

ESP32 FCC Certification

I want to build an esp32 device using the esp32-pico-d4 chip that I will sell to hobbyists. However, I recently came across something called the FCC. It requires radio devices to get certified which ...
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49 views

In HLW8012 schematic, where should the Referenced ground be connected

In the datasheet of HLW8012, the both 33nF capacitors , 1K resistor and 0.1uF capacitor are connected to GND. I'm not sure where should I connect those ends of components marked with GND symbol, (To ...
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38 views

ESP8266 Webserver not reachable after 2 minutes from reset

I have a Keyes Espressif ESP8266 NodeMCU, I have two LEDs that I want to control which are connected to the ESP. When I open the webpage http://10.0.0.5/5 after ...
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2answers
40 views

How to hook four strain gauges ( 5 wire) to esp32

I have four strain gauges (50kg) with 5 wires each (red, black, white, green, yellow) and want too measure weight of a platform. I assume those should be hooked to hx711 load cell amplifier and esp32 ...
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1answer
48 views

which is faster GPRS vs 4G on arduino?

I am using Sim800 GPRS to send data to MySQL server online. I use Arduino mega 2560 for one update in MySQL, it takes 1-2 seconds to run required AT commands If I use a 4G module like SIM7000E will ...
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39 views

NodeMCU ESP8266 DHT22 reading nan (2147483647)

I am new to electronics and microcontrollers and hope this is the right spot on StackExchange. I have been playing around with an Arduino Micro, connecting different sensors and a display and display ...
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22 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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33 views

ESP32 with LNA and PA

I would like to add a low noise amplifier and a power amplifier to the ESP32. As you may know there is only one RF output on the chip. I was thinking of adding an RF switch, and switching between ...
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1k 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 ...
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3answers
112 views

How to measure AC current using ACS712 and interface with ESP32?

Actually, I want to measure the AC current using ACS712 connect with ESP32 module. I know this module only works under 3.3v. So, I used voltage divider circuit and step down 5v to 3.3v which is being ...
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65 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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2answers
45 views

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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24 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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32 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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18 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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2answers
53 views

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

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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61 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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36 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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50 views

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

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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60 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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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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46 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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59 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
42 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
40 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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118 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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30 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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71 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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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
42 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
968 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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90 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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32 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 ...