Questions tagged [esp8266]

An IC that offers Wi-Fi networking compatible with b/g/n standards. It also has integrated TCP/IP protocol stack. Extremely popular along IoT community as a low cost and powerful board.

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2 votes
3 answers
526 views

Send values from Arduino Uno to Wemos D1 R1

I have a weather project in which I have to measure the temperature and humidity (DHT22 sensor), the pressure, and other things, and then show them on a local web page (using a Wemos D1 R1) in either ...
-2 votes
0 answers
34 views

ESP8266 error ""ets Jan 8 2013,rst cause:2, boot mode:(1,6)"" [closed]

I was working through the instructions for the Uno Wifi (XC4411 with ESP8266; https://www.jaycar.co.nz/medias/sys_master/images/images/9701844287518/XC4411-manualMain.pdf) and using the provided code (...
1 vote
0 answers
304 views

rst cause:2, boot mode:(3,6) caused by pointer reference

I am experiencing an unusual issue with my code. I have a LOLIN WEMOS D1 mini Lite and I am using the Arduino IDE to upload the sketch. The version of the board is 3.0.2 for ESP8266. The problem is ...
0 votes
2 answers
26 views

ESP8266 Wemos D1 min pro - how to change TCP_SND_BUF?

Is there any way to change the TCP send buffer size (TCP_SND_BUF) on this module ? Now it is equal to TCP_SND_BUF = 2 * TCP_MSS = 2 * 1460 = 2920. Editing lwipopts.h doesn't make any difference. The ...
0 votes
0 answers
19 views

Connecting Firebase to ESP8266 on proteus [closed]

I am working on a project which will require me to connect my Arduino with Firebase, I currently don't have sufficient funds to get the necessary physical gear so I thought of using proteus. Now ...
1 vote
1 answer
51 views

ESP8266 Pulling Credentials from SD makes esp unable to connect

I'm trying to set up a wifi SD server and i want to put the wifi credentials in a config.txt file on the sd. The entire code works fine. when i dont use the sd credentials but when i do i run into ...
0 votes
0 answers
12 views

NodeMCU srv:listen out of memory on second save to esp

I have flashed my esp8266 12f amica with the latest nodemcu firmware (SDK 3.0.1). I am using ESPlorer to code on the esp. I am using a code loosely based on the snippets shown in nodemcu's dev guide. ...
0 votes
1 answer
35 views

Determining ArduinoJSON document size based on file size

I'm trying to effectively allocate a doc's size, based on the size of the file saved in flash of ESP8266. Is there a way? For example: file.size() X 1.5
0 votes
0 answers
33 views

Arduino + esp8266 : Timeout linked to length of code?

I have an arduino and an esp8266 12f (NodeMCU) connected via Serial (SoftSerial on Arduino's side). It works well when sending AT commands directly from computer via a USB-Serial connection, esp8266 ...
1 vote
0 answers
367 views

Can SoftwareSerial be used in an ESP01

I am using ESP01 as a microcontroller that retrieves information from Firebase and sends them over serial to an Arduino Uno for other uses. I am not using NODEMcu since it has few analog pins and ...
0 votes
0 answers
24 views

DHT22 is returning nan when connected to ESP8266, works normal when connected to Arduino Uno

I bought this ESP8266 nodeMCU v0.1(this version number is on board) and some wired DHT22 sensors. When I try sensors on arduino uno, they work normal. But, when I connect them to this nodeMCU I get ...
0 votes
1 answer
38 views

PWM on Wemos D1 Mini (esp8266 chip) does not work

I am working on a hobby project: creating an rc-(radio controlled)-toy car. I'm working with a Wemos D1 Mini (esp8266) microcontroller, L298N H-bridge (for controlling the motor) and I'm using the ...
2 votes
1 answer
439 views

ESP8266 wakeup from deep sleep: Both by timer and button?

In a project powered by batteries, the ESP8266 should go to deep sleep for long time, having RF disabled. After some number of sleep cycles, it shall restart with RF enabled, synchronize time via NTP, ...
4 votes
4 answers
10k views

Convert String to IPAddress

How can i convert a String to IPAddress on arduino / esp ? etc. "192.168.1.2" -> IPAddress(192, 168, 1, 2) Tried this void setup() { Serial.begin(115200); IPAddress apip; const char *...
0 votes
0 answers
48 views

Serial com issue between Arduino and esp8266-12f

I have a serial communication issue between a Arduino Uno and a NodeMCU (ESP8266 12f) that I do not understand. The setup is the following. Arduino uno powered by USB cable plugged on computer with : ...
0 votes
1 answer
24 views

PubSub'a - KeepAlive function not as expected

I'm using PubSubClient to pub/sub MQTT messages using ESP8266. As far as I know "Keep-alive" detects when a client went off-line after a period of time. I'm using library's example ...
0 votes
0 answers
27 views

Fail passing ArduinoJSON [duplicate]

I'm storing parameters file on ESP8266 flash, using LittleFS.h and ArduinoJSON.h. In case of a failure getting stored values from flash, local defaults are used (stored locally in myIOT_defs[]). When ...
1 vote
1 answer
37 views

NodeMCU ESP8266 - Which pins can I use? [duplicate]

I'm trying to connect 3 LEDs to a LoLin NodeMCU ESP8266. It seems that several or "all" of the digital pins have some special use that prevents me from using them. If I connect the LEDs (...
0 votes
2 answers
289 views

ESP8266 not accessing PHP file

I'm trying to control NodeMCU via Android application and I can control NodeMCU easily but when I added the URL to hit the PHP code to enter data in MYSQL, neither NodeMCU is controllable nor NodeMCU ...
0 votes
1 answer
83 views

ESP8266 -01 doesn't reply with anything

The problem started when I tried to upload the Blink program to the module, it uploaded with no issues through Arduino but after that the blue LED didn't blink. I searched a lot for it and found that ...
-1 votes
1 answer
771 views

RDM6300 library not working on ESP8266

I have a RDM6300 RFID module which I am trying to connect to an ESP8266 by using rdm6300.h library. I had it all up an running all along with other components but we had connected to the ESP8266 but ...
1 vote
1 answer
475 views

Can't connect my ESP-12F to WiFi with my Arduino Uno

Recently I bought this wifi adapter for my IOT projects that I connected to my arduino uno that seems to not working. I have tried with the arduino ESP8266WiFi library with RX connected to pin 0 and ...
0 votes
1 answer
610 views

How to send int array with ESP8266 http post request?

I'm reading RFID cards' UID with an ESP8266 and trying to send that information to my web server hosted on a Raspberry Pi. I'm currently storing the UID in an int array, but the http.POST(); function ...
1 vote
0 answers
31 views

Accessing HTTPS server of ESP8266 through fetch

I have been messing around with this application for a while but seem to keep hitting roadblocks. I am trying to have a public HTTPS page make a fetch to a private ESP8266. As you can guess I ran into ...
-1 votes
3 answers
811 views

HD44780 display incorrectly black-on-blue instead of white-on-blue

I have a generic HD44780 compatible 16x2 LCD display, with an already soldered on PCF8574 module. Its backlight is blue, and the characters are supposed to be white (on blue). It is connected to a ...
2 votes
1 answer
443 views

ESP8266 - How to recieve UDP multicast packet?

how can I recieve udp multicast packets in ESP8266? I have this piece of code: #include <ESP8266WiFi.h> #include <WiFiUdp.h> const char* ssid = "my_wifi_ssid"; const char* ...
0 votes
1 answer
2k views

ESP send data to Arduino

I'm trying to send data from my esp to my arduino using serial using the following codes : esp : server.on("/drive",HTTP_GET, handleDrive); void handleDrive() { server.send(200,"text/html", "...
2 votes
1 answer
64 views

ESP8266 soft resets when using a GPIO Expander

In my project I'm trying to use a PCF8574 to drive some peripherals, since the ESP8266 doesn't offer all the GPIO pins I need, however I seem to be having problems at the most basic level of driving ...
0 votes
1 answer
725 views

Uploading Firmware to Atmega1284p using ESP8266 with AVRISP as programmer

I am trying to flash a new Firmware to my Ender 3 Pro. I am using the ESP8266 as an ISP via AVRISP over Wifi. I have a 10mF capacitor between the ground and reset of the ESP8266 I followed this ...
0 votes
1 answer
2k views

ADS1115 : measuring 5v voltages and powering with 3.3v

I have a project where I need to measure 0 - 5 V. I’m using a ADS1115 to have a better precision, connected to a ESP12. Since the ESP is only 3.3 V tolerant and the ADS powered by 5 V (...
10 votes
5 answers
81k views

How to I make the Tx and Rx pins on an ESP-8266-01 into GPIO pins?

When programming an ESP-01 with Arduino IDE, how can I make the Tx and Rx into a generic I/O pins reliably? I think there's a command to swap the Tx and Tx with other pins. I tried serial.swap() but ...
5 votes
1 answer
2k views

Non-blocking MQTT library

Are there any MQTT libraries that do not block while connecting? I'm currently using PubSubClient, and the connection part contains this code: https://github.com/knolleary/pubsubclient/blob/master/...
0 votes
2 answers
2k views

Connecting multiple topics- MQTT

I'm configuring an ESP8266 using Arduino Uno. I have several MQTT topics I wish it to subscribe, and I do not want to repeat code 3 or 4 times ( in Python I would have created a list - and make a for ...
3 votes
3 answers
4k views

Arduino OTA port not updating in Arduino IDE

The OTA (from the ArduinoOTA library) on my ESP8266 does not show up in the programming ports on the Arduino IDE unless I restart the IDE. Even when I plug in a usb cable and the ports list updates ...
0 votes
1 answer
2k views

NodeMCU stops responding after several hours

I'm controlling some devices through a relay and a NodeMCU, it works fine and reconnects without problem in the meantime I'm testing it, but after I leave it like for 3 or more hours, it stops ...
0 votes
1 answer
115 views

How to append to array of Strings in arduino?

Here is my code: char *StrAB[] = {"29 EC C7 C1", "69 5B C9 C2", "22 3B 83 34", "12 BF BF 34", "C6 78 8E 2C" }; void setup() { Serial.begin(9600)...
0 votes
0 answers
31 views

relay issue at boot in wemos d1 r1

Hi I have a wemos d1 r1 and I want to activate a relay with rc522 RFID module. the problem is that when I connect the board to power or when I reset it, or when I'm uploading the code, the led on the ...
1 vote
1 answer
873 views

Detect power interruption on NodeMCU

Im using a 5v 1A power supply and connected to VIN pin on the NodeMCU. I also use 18650 battery to keep NodeMCU running in case the power supply shuts off due to power interruption. I'm planning to ...
-1 votes
1 answer
54 views

NodeMCU programming without USB port [closed]

Recently, I've been attempting to build an anti-collision detection system for uses in a car. I bought several nodeMCU units and wil use one as a WiFi hub. In the course of experimenting, I broke off ...
0 votes
0 answers
22 views

RA-02 LoRa transfer problem

i've connected 2 RA-02 modules to my ESP8266 s. Both are capable of transmitting and receiving data between each other. and also esp8266 s are represented as access points to whatever client that ...
0 votes
2 answers
876 views

Detect the end of playback of a MP3 file with DFPlayerMini / DFRobotDFPlayerMini.h library

For a project I'm doing I've used an ESP8266/12e, a RTC Module DS3231 and a DFplayerMini Basically it's a caller for birds and it has to play a 12-minute long MP3. The MP3 file should be played for 2 ...
1 vote
1 answer
145 views

Esp8266: Linux - fatal: No names found and undefined reference to `app_entry_custom()'

as Gentoo user I build everything from sources, but I have problem with building toolchain for esp8266. I came up with this script: #!/bin/sh # note: eselect python2 before, because of gcc # ...
1 vote
2 answers
589 views

esp8266 + octocoupler relay: WDT reset when using AC current

I'm trying to switch on bulb via 4 channel 5V optocoupler relay controller from ESP8266 using WIFI Access point. All my connections looking fine and i can able to connect WIFI SoftAP and send signal ...
0 votes
2 answers
2k views

Choosing Right Power Supply for Arduino - ESP8266 - HC-SR04

If I make connections like you see in picture below, will it work? Will I damage ESP or HC-SR04? As I know; HC-SR04 (VCC) -> 5V ESP8266 (VCC) -> 3.6V ESP8266 (RX/TX) -> has 5V tolerance ? I ...
-2 votes
1 answer
35 views

how to save float with 3 decimal places [duplicate]

i am transmitting sensor data from my atmega328p to my esp8266. The Sensordata has 3 decimal places. The esp8266 sends this data to my pc and there I see only two digits. This is because the data is ...
1 vote
1 answer
49 views

Node MCU Esp12-E does not support server accept function

I am trying to get a web server to run on the ESP12E on the Node MCU variant, and following the example from the esp8266 documentation page here. But the code does not compile, throwing the following ...
0 votes
1 answer
347 views

How to read serial data without any blocking using ESP8266

I'am deconding one electronic device serial protocol and using ESP8266 for this task. Device is sending 202 byte data constantly and I figured out begining and the end. Whole packet looks like: 71 ...
0 votes
1 answer
916 views

Wemos D1 mini freezing after a few minutes

I´m using a Wemos D1 mini board to control a RGB LED Strip and programmed a simple code with the Arduino IDE. The Wemos conects to my Internet just fine and with the IP adress I can change the RGB ...
1 vote
1 answer
123 views

Why when I try to connect my ESP8266 to my node sever in my localhost it keep getting disconnect and connect?

I think the issue is within the library because I have try to implement this code according to the tutorial that I found in YouTube Youtube. The discussion of this tutorial is the first they implement ...
1 vote
1 answer
6k views

ESP8266 - One server sending data to multiple clients

I have a few arduinos with ESPs, one of which is set up to measure temperature, and I'd like to have it send commands to other connected arduinos to perform various functions (open/close valves etc.) ...

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