Here are some useful articles on electronics and microcontrollers.
Digital I/O expansion methods.
ESP8266 Webserver: This code shows you how to use lua to create a webserver using html button inputs to contrtol an LED on the ESP module.
How to flash nodemcu firmware into a ESP8266 so you can use the LUA scripting language.
Nodemcu examples starting off wioth simple ones and progressing to wifi coding. This is an excellent tutorial to start learning how to use nodeMCU with lua.
Find out how to download the ESPLorer and use it to upload lua scripts
How to use the TCS230 (/TCS3200) Color detector chip and easily add it to any of your projects.
The Essential Guide to the MAX7219; What it is and how you can easily use one in any of your projects.