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6 votes
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Need help with parsing NWS JSON weather alerts causing reset on ESP8266

By default, the size of the stack is limited to 4KB on ESP8266, so you cannot store an 8KB document there. To fix this issue, replace the StaticJsonDocument with a DynamicJsonDocument to move the ...
Benoit Blanchon's user avatar
5 votes
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ESP8266 I2C doesn't respond

I2C slave doesn't work on esp8266 because it doesn't have hardware support for I2C. From the esp8266 Wire library documentation: Wire library currently supports master mode ... https://arduino-...
Juraj's user avatar
  • 17.9k
4 votes
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ERROR: return reinterpret_cast<T>(pgm_read_ptr(p));

With the info from the link Fahad provided in the comments, I can only offer a guess: Your ESP8266 board definitions are outdated and the old version of the ESP8266 board definitions contains a bug. ...
orithena's user avatar
  • 499
4 votes
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Mobile hotspot with wemos d1 mini

By default the iPhone hotspot is 5GHz only, which is why your ESP8266 can't see it. The ESP8266's WiFi radio is 2.4GHz only. To enable 2.4GHz on the iPhone hotspot, turn on the "Maximize ...
romkey's user avatar
  • 1,544
4 votes

Please help me with my project of water pump relay switching too fast

The problem lies in the specification itself. According to your rules, what should the pump do if the water level is exactly 2 cm? Granted, there is no such thing as an exact physical measurement. But ...
Edgar Bonet's user avatar
  • 42.8k
4 votes

OLED and Wifi not working together on ESP8266 Heltec NodeMCU

I managed to solve the issue and figure out what the problem is. I put here an answer for reference, if this question appears again. It turns out that the reset of the OLED is important. It is easy to ...
Fabian's user avatar
  • 151
4 votes

Why does an ESP01 WiFi module reset when it's connected to a DC motor/water pump?

The abs. max. supply voltage for the ESP-01s is 3.6 V; leaving out the voltage regulator and using 5 V for its power supply will likely have killed or at least damaged it. Also, the water pump needs a ...
ocrdu's user avatar
  • 1,775
4 votes
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Sketch halts if button is pressed on boot

Description of pin D3 from this ESP8266 pinout reference: connected to FLASH button, boot fails if pulled LOW So you cannot pull this pin to LOW during boot, as it will keep the ESP in flash mode. ...
chrisl's user avatar
  • 16.1k
2 votes

Where to define web server callback functions so they can access server object? (ESP8266WebServer library)

put your server declaraition outside the constructor and call a class callback : #include <Arduino.h> #include <ESP8266WiFi.h> #include <ESP8266WebServer.h> ESP8266WebServer server(...
eltharin's user avatar
2 votes

An error is shown as sendCommand was not declared in this scope.how to rectify it

First thing: format your code properly. Statements that are at the same nesting level should have the same amount of indenting. If you find this rule too hard to follow, you can try the auto-format ...
Edgar Bonet's user avatar
  • 42.8k
2 votes

ARDUINO DC Motor Control over IR Sensor INPUT

You have the general idea. Your code looks a bit cluttered. Comments are not part of the program, keep them away from the code. The if statements reduce to if (true), that means that == true part is ...
jsotola's user avatar
  • 1,444
2 votes

Problem with using PubSubClient, the "callback" function doesn't seem to work correctly

From the PubSubClient library documentation: Internally, the client uses the same buffer for both inbound and outbound messages. After the callback function returns, or if a call to either publish or ...
Bra1n's user avatar
  • 1,008
2 votes

How to pass AT commands to Lora from ESP32 UART?

I am new to Lora module and ESP32 and only playing around for a week. I have successfully sent AT commands to RYLR998 module via ESP32 and received messages via other RYLR998 connected to another ...
Altinem72's user avatar
2 votes
Accepted

sim800l gsm module response isn't completed

Just for someone in the future who is having the same issue. the problem was because of the boadrate 115200 is pretty fast for a software serial implementation so i just changed it to 9600 sim800l....
Mohamed Essam's user avatar
2 votes
Accepted

ESP8266 seems to be killing a while loop

You can't trap an ESP in a while loop like that. There are things it needs to get back to main and do between loops. Instead, let the loop function be your loop. Make the while statements if ...
Delta_G's user avatar
  • 3,251
2 votes

ArduinoJson library: how much space to allocate for serialized buffer?

You're asking about code that looks like this: StaticJsonDocument<128> payload; char payloadSerial[???]; ... int status = https.POST(payloadSerial); strncpy(payloadSerial, https.getString()....
romkey's user avatar
  • 1,544
2 votes

Understanding ESP8266 OTA Updates: A Question on Limitations

No each update overrites the oldest one (if present) so there are only ever a maximum of 2 versions in flash
Brian Kelly's user avatar
2 votes

Need help with parsing NWS JSON weather alerts causing reset on ESP8266

There is a good clue in the first line of your reported error: 21:13:07.521 -> wdt reset The ESP-8266 Watchdog Timer (WDT) will reset the device if it has not been correctly 'fed' for a period of ...
rolinger's user avatar
  • 204
2 votes

ESP8266 I2C doesn't respond

The devices must share a common ground, and also you may need 4.7k pull-up resistors on both SDA and SCL. See http://gammon.com.au/i2c for a whole lot more detail.
Nick Gammon's user avatar
  • 38.1k
2 votes

Fixing a pedestrian traffic light sequence pattern in a cycle using millis and without delay

Here is some simplified example code that might be useful to you. It keeps the logic and the LED control separated by the use of flags. Simulation is at https://wokwi.com/projects/389132610627050497 /...
jsotola's user avatar
  • 1,444
2 votes
Accepted

strip.clear() is not clearing/turning off the NeoPixel strip after resetting the ESP8266

We can have a look at the clear() function inside the Adafruit_Neopixel library. In Adafruit_Neopixel.cpp you can find at line 3396 (searching for clear(void) will get you there): void ...
chrisl's user avatar
  • 16.1k
1 vote

NodeMCU V3 GOT OVERHEATED AND DIED

Based on https://lastminuteengineers.com/l298n-dc-stepper-driver-arduino-tutorial/, you have wired your servo incorrectly. The third pin on the bottom blue connector (VSS) is the second input, not the ...
Draco-S's user avatar
  • 111
1 vote

Errors when trying to connect esp8266 to firebase

fixed by downgrading my esp8266 version to 2.7
NyK's user avatar
  • 51
1 vote

ESP8266 Wifi connection problem

I don't have enough reputation to comment, otherwise this would be a comment, but you could ask your landlord to change the password. If he says no, you could say one of your devices can't type that ...
Iliketurtles's user avatar
1 vote
Accepted

How much maximum current do the Arduino Wemos D1 (R1 & R2) consume?

It is possible to measure how much it is using from any of the pins? Put an ammeter (multimeter in current mode) in series with the power supply and measure it, when configured in the way you intend ...
Nick Gammon's user avatar
  • 38.1k
1 vote

Powering a NodeMCU as well as a GSM module

After a bit of researching, I have found the following solution:- A DC-DC buck converter (such as the LM2596) can convert a 12 V 2A rated power supply down to 4 V (the value is adjustable) which can ...
vasantha raj's user avatar
1 vote
Accepted

Error while uploading "A fatal esptool.py error occurred: Write timeout"

The "most common reason" mentioned in this answer was actually the problem I had. Unfortunately I was using a charge only cable even though the cable package clearly said it was a data-cable....
sribasu's user avatar
  • 131
1 vote

Error while uploading "A fatal esptool.py error occurred: Write timeout"

I had the same problem. My solution: Program for blinking led ESP8266MOD (cheap Chinese esp8266mod module) I used Arduino IDE 2.1.0 info from https://vimalb.github.io/IoT-ESP8266-Starter/Lesson_01/...
JAM's user avatar
  • 11
1 vote

Error while uploading "A fatal esptool.py error occurred: Write timeout"

I've run into this a bunch recently, and typically, but not always, the cause is that I was using a GPIO pin that was reserved and couldn't be used during boot up. It's surprising how many of the pins ...
kylemohr's user avatar
1 vote

what is 400 bad request and how to solve this

The server name does not belong to the GET request line: it has to be provided in the Host request header. Try something this: server.println("GET /update?api_key=ME5K4JWXT2ZBSBZ8&field1=0 ...
Edgar Bonet's user avatar
  • 42.8k

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