Comments on: ESP32 Web Server with Slider: Control LED Brightness (PWM)

By: galina

galina — Mon, 09 Jun 2025 21:43:25 +0000

How about horizontal Battery Level Widget, do you have example ?

By: Sara Santos

Sara Santos — Mon, 09 Jun 2025 16:05:46 +0000

In reply to Galina.

Hi.
You can use something like Preferences.h to save the values permanently whenever there’s a change: https://randomnerdtutorials.com/esp32-save-data-permanently-preferences/

Regards,
Sara

By: Galina

Galina — Mon, 09 Jun 2025 11:20:29 +0000

Hi I practicing on your slide program – Control LED Brightness (PWM). There are some issue which can be improvement. 1.Value slider is unknown until you release the slider – should be visual all the time when slider is moved.
2. Value of the slider is 0 after power is turned off and on – the value should stay the same as was before turning power off.

Can you fix that ?
Regards
Galina.

By: Neb

Neb — Thu, 05 Sep 2024 16:40:06 +0000

In reply to Neb. Never mind, user error

By: Neb

Neb — Thu, 05 Sep 2024 16:31:11 +0000

My ESP32 devkit v1 board crashes on slider move every time…

By: Sara Santos

Sara Santos — Tue, 06 Aug 2024 08:42:16 +0000

In reply to Nate.

Hi.
Which example are you trying to run?
Regards,
Sara

By: Nate

Nate — Tue, 30 Jul 2024 19:38:36 +0000

I am trying to the PWM to two different pin using the ledcAttachChannel function and i am getting the following error message. i have not found anything useful to try and debug.

M:\Nate\ESP32_webserverCode\esp32_PWM_MOTORcontrol_momentary\esp32_PWM_MOTORcontrol_momentary.ino:20:11: error: expected constructor, destructor, or type conversion before ‘(‘ token
20 | ledcAttach(enable1Pin, freq, resolution);
| ^
M:\Nate\ESP32_webserverCode\esp32_PWM_MOTORcontrol_momentary\esp32_PWM_MOTORcontrol_momentary.ino:21:11: error: expected constructor, destructor, or type conversion before ‘(‘ token
21 | ledcAttach(enable2Pin, freq, resolution);
| ^

exit status 1

Compilation error: expected constructor, destructor, or type conversion before ‘(‘ token

By: Sara Santos

Sara Santos — Sat, 29 Jun 2024 13:53:42 +0000

In reply to Bill Wallace.

Hi.
What version of the library are you using?
Regards,
Sara

By: Bill Wallace

Bill Wallace — Sat, 29 Jun 2024 02:10:14 +0000

I am on board version 3.0.2. Getting similar problem

C:\Users\xx\Documents\Arduino\libraries\ESPAsyncWebServer\src\WebAuthentication.cpp: In function ‘bool getMD5(uint8_t*, uint16_t, char)’:
C:\Users\xx\Documents\Arduino\libraries\ESPAsyncWebServer\src\WebAuthentication.cpp:99:3: error: ‘mbedtls_md5_starts_ret’ was not declared in this scope; did you mean ‘mbedtls_md5_starts’?
99 | mbedtls_md5_starts_ret(&_ctx);
| ^~~~~~~~~~~~~~~~~~~~~~
| mbedtls_md5_starts
C:\Users\xx\Documents\Arduino\libraries\ESPAsyncWebServer\src\WebAuthentication.cpp:100:3: error: ‘mbedtls_md5_update_ret’ was not declared in this scope; did you mean ‘mbedtls_md5_update’?
100 | mbedtls_md5_update_ret(&_ctx, data, len);
| ^~~~~~~~~~~~~~~~~~~~~~
| mbedtls_md5_update
C:\Users\xx\Documents\Arduino\libraries\ESPAsyncWebServer\src\WebAuthentication.cpp:101:3: error: ‘mbedtls_md5_finish_ret’ was not declared in this scope; did you mean ‘mbedtls_md5_finish’?
101 | mbedtls_md5_finish_ret(&_ctx, _buf);
| ^~~~~~~~~~~~~~~~~~~~~~
| mbedtls_md5_finish
C:\Users\xx\Documents\Arduino\libraries\ESPAsyncWebServer\src\AsyncWebSocket.cpp: In member function ‘void AsyncWebSocketClient::_queueMessage(AsyncWebSocketMessage)’:
C:\Users\xx\Documents\Arduino\libraries\ESPAsyncWebServer\src\AsyncWebSocket.cpp:726:5: error: ‘ets_printf’ was not declared in this scope; did you mean ‘vswprintf’?
726 | ets_printf(“ERROR: Too many messages queued\n”);
| ^~~~~~~~~~
| vswprintf
C:\Users\xx\Documents\Arduino\libraries\ESPAsyncWebServer\src\AsyncEventSource.cpp: In member function ‘void AsyncEventSourceClient::_queueMessage(AsyncEventSourceMessage*)’:
C:\Users\xx\Documents\Arduino\libraries\ESPAsyncWebServer\src\AsyncEventSource.cpp:189:7: error: ‘ets_printf’ was not declared in this scope; did you mean ‘vswprintf’?
189 | ets_printf(“ERROR: Too many messages queued\n”);
| ^~~~~~~~~~
| vswprintf
Multiple libraries were found for “WiFi.h”
Used: C:\Users\xx\AppData\Local\Arduino15\packages\esp32\hardware\esp32\3.0.2\libraries\WiFi
Not used: C:\Program Files (x86)\Arduino\libraries\WiFi
Using library WiFi at version 2.0.0 in folder: C:\Users\xx\AppData\Local\Arduino15\packages\esp32\hardware\esp32\3.0.2\libraries\WiFi
Using library Network at version 1.0.0 in folder: C:\Users\xx\AppData\Local\Arduino15\packages\esp32\hardware\esp32\3.0.2\libraries\Network
Using library AsyncTCP at version 1.1.4 in folder: C:\Users\xx\Documents\Arduino\libraries\AsyncTCP
Using library ESPAsyncWebServer at version 3.1.0 in folder: C:\Users\xx\Documents\Arduino\libraries\ESPAsyncWebServer
Using library FS at version 2.0.0 in folder: C:\Users\xx\AppData\Local\Arduino15\packages\esp32\hardware\esp32\3.0.2\libraries\FS
exit status 1
Error compiling for board WEMOS D1 R32.

I am just trying this program for the first time.

By: Sara Santos

Sara Santos — Tue, 25 Jun 2024 09:01:21 +0000

In reply to Frank De Hert. Are you using version 3?