Many questions about extension builder


First of all, what should I do to try the extension without publishing?


Hi dai5_jp,
You can test it before publishing.


After dropping in this state

It becomes this.


May I have the screen shot and the file name?


After dropping in this state

It becomes this.


The file name is robopro_shield.mext.


Hi there,

If you are using the mBlock V5.0.1, please delete the other version that are auto selected like below:

And just in case you need it, here is a guide of checking which version the software is:


I did it once. However, if you do it for the second time, (filename) Updated successful will be displayed.



  1. Open mblock and add extensions to the codey rocky device.
  2. Extensions were able to used.
  3. Close the mblock.
  4. Open the mblock again.
  5. Extensions were missing.
  6. When I added it again, (filename) Updated successful was displayed, but the extension was not added.
    Supplement: Actually it was an extension for arduino, but I accidentally added it to codey.


How do I add code to a block? :frowning_face:


Hi there,

here is the documentation of how to add code to blocks:


Here are some FAQs for your reference just in case you need them. :slight_smile:


How do I use my own .h file with #include?
@mBlock,please tell me.


I have the same question. I developed an Extension to use the FastLED library. How can I add c-Code to the Mblock5-Blocks?


Support device/sprite:
In the description of this, you will specify the device id, but what is the arduino id?


Hi! Please try to enter your own codes in the “Common code” section as follow:


Hi there,

Please enter your own codes right in the “Common Code Settings” section as follow:


Hi there,

Now mBlock 5 already supports Arduino Mega 2560 (ID: arduino_mega2560) and Arduino Uno (ID: arduino_uno). We will improve the settings in the next version so that you can just select the ID instead of manually entering it. :grinning:


I would like to use .h files, but it only supports .js files.


Hi there, I added my .h files in transcode settings (the only place that I could do it), but then I don’t now how to declare it in the block settings. If I include it as “myFile.h”, the compiler doiesn’t find it.
Someone can help me? Thanks!