I finished the port of the Raspberry Pi source code for the ePaper, as a module for the nodemcu-firmware project. I forked the original repository and added it as the Lua module "epd", see here:

https://github.com/FrankBuss/nodemcu-firmware

Then I installed the Mosquitto MQTT broker and wrote a Lua script for the module, that subscribes to the topic "display". The messages are interpreted as links to binary files which are loaded from a webserver and then displayed on the display, see init2.lua for the details in the new github repository for this project:

https://github.com/FrankBuss/wifi-epaper

With the Mosquitto test client I can send messages to the module from the PC, for example to load the image wifi-epaper.bin:

mosquitto_pub -t "display" -m "wifi-epaper.bin"

See the instructions on this website for details how to setup your own MQTT broker and for some explanations how to use it from Lua. The bin files are located on the webserver and are created with the test.py Python script from PNG images. The nodemcu_float_master_20170414-2230.bin file is the precompiled firmware image for the NodeMCU module, with the new epd Lua module.

You can see the connecting scheme in the LibreOffice spreadsheet pins.ods on github. It gets quite complicated with all the different internal and external names. A spreadsheet is very useful for such a task so that you don't get lost.

This is how it looks like when it is running:

The current consumption in idle mode is still quite high with about 22 mA and some peaks from time to time, maybe I can find some sleep mode for the module, it doesn't need to react immediately. When receiving a new image and updating the display, it needs up to 80 mA (at 3V) for some seconds. But it is possible to run the NodeMCU module with less power, if you don't need immediate updates of the display, but poll it like every minute.