Where i can find the file .h

Hi to all,

Pls somebody help me,im a beginner.I would like to ask where i can find the file .h … Or how can i upload to ESP12?
Im getting error if i try to test

Thanks in advance

just ask google , lol

im trying but i dont know what to search.
Can u send me a few links.

pls help.

.h files are used in libraries. These aren’t uploaded directly to the ESP, but are used by the Arduino IDE (or whatever other compiler you use) when the firmware code is being compiled.

If your compiler is telling you that it can’t compile the firmware because a .h file is missing then it means you haven’t installed a library that is referenced in an include statement at the top of your code.
Read the compiler message then do a google search for the name of the missing library. Also google how to install a library .zip file in Arduino.


1 Like

Hi Pete,

You are my man:slight_smile:

Now i do as u said but i have one problem wich i dont understand how to solve

: error: expected constructor, destructor, or type conversion before ‘control’

  • HVAC control for a “2-pipe” radiator system.


exit status 1
expected constructor, destructor, or type conversion before ‘control’

I’m guessing that you’ve copied the original code at the top of this thread, but missed out the very first line of code:

This means that the following lines, which are comments, are being treated as executable code by the interpreter and they don’[t make any sense.


Now im almost done only this problem come up:

What can i do?

Archiving built core (caching) in: C:\Users\Csaba\AppData\Local\Temp\arduino_cache_757797\core\core_esp8266_esp8266_nodemcu_CpuFrequency_80,FlashSize_4M1M,LwIPVariant_v2mss536,Debug_Disabled,DebugLevel_None____,UploadSpeed_115200_40a2077da280dd95dadf99e816123d2e.a
sketch\hvacther2.ino.cpp.o:(.text._Z10TempUpdatev+0x28): undefined reference to `DHT::readTemperature(bool, bool)’

sketch\hvacther2.ino.cpp.o:(.text._Z10TempUpdatev+0x55): undefined reference to `DHT::readTemperature(bool, bool)’

sketch\hvacther2.ino.cpp.o: In function `String::operator+=(int)’:

C:\Users\Csaba\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\2.4.0\cores\esp8266/WString.h:133: undefined reference to `DHT::begin()’

sketch\hvacther2.ino.cpp.o: In function `setupAP()’:

C:\Users\Csaba\AppData\Local\Temp\arduino_modified_sketch_550806/hvacther2.ino:236: undefined reference to `DHT::begin()’

sketch\hvacther2.ino.cpp.o: In function `BlynkProtocol<BlynkArduinoClientGen >::begin(char const*)’:

C:\Users\Csaba\Documents\Arduino\libraries\sketch_feb17a/Blynk/BlynkProtocol.h:92: undefined reference to `DHT::DHT(unsigned char, unsigned char, unsigned char)’

sketch\hvacther2.ino.cpp.o: In function `_GLOBAL__sub_I_Blynk’:

C:\Users\Csaba\AppData\Local\Temp\arduino_modified_sketch_550806/hvacther2.ino:137: undefined reference to `DHT::DHT(unsigned char, unsigned char, unsigned char)’

collect2.exe: error: ld returned 1 exit status

I’d say that you either installed the DHT library incorrectly, or you’re using a different library to the one that the original author used.
My money would be on the first option.

Explain the exact steps that you went through to download and install the DHT library into the Arduino IDE.


it will be better if you post your code
don’t forget to format before you post it

Thanks guys,i will try later the original code and also the other dht.

Thanks again

it seems that the DHT wich i install is not a good one.I put 2 kind still not ok.
Can somebody send me a link with one wich is working with this code?


I have this library installed and the original HVAC code compiles fine for me:

I think you’re probably installing the libraries incorrectly, or you have multiple DHT libraries installed and the Arduino IDE doesn’t know which one to use.

Download the zip file of the library from the link above by clicking Clone or Download then Download ZIP. Save the .ZIP file somewhere then go to the Ardiono IDE and choose Sketch/Include Library/Add .ZIP Library. Navigate to the downloaded .zip file and clik Open.

In the Arduino IDE, go to File/Preferences and check the box that says “Show verbose output during: compilation”.
Re-compile your code and if you get an error message post the full compile message.


Hello Pete,
Thanks for your help now everything is,working well.

Thanks guy