I just went through building and programming the IR MQTT tranceiver and want to thank mix_at_pl for the great work.
The building is straight forward following the schematic.
For the programming I installed the Platformio IDE following the instructions from Redirecting.... You need to have Python 2.7.x installed for it to work correctly.
Once Platformio is loading with no errors, click on “Open Project” and select the folder mqtt-ir-transceiver-master (which is downloaded and unzipped from https://github.com/enc-X/mqtt-ir-transceiver/archive/master.zip).
From the list with files in the left tab open the platformio.ini and change the upload_port = com12 to the correct port with your ESP8266
Select “PlatformIO/Build” from the menu on top and wait for the build to finish. The needed libraries will be downloaded and installed automatically.
If no errors you will see “No issues” message on the bottom.
Next click “PlatformIO/upload” and keep an eye on the messages. If the COM port is not correct you’ll see errors ( error: Failed to open com12 etc).
Once successfully uploaded, reboot your ESP.