Strav's blog

Here is an article on creating a basic web service.

Create a Basic Web Service Using PHP, MySQL, XML, and JSON

Here's a YouTube video on setting up HASSIO and Tasmotized Sonoff

UPDATED: get HASSIO and Tasmotized Sonoff up and running!

Here's a link to a YouTube clip detailing an inexpensive DIY Temperature, Humidity, Light, Motion and RGB LED sensor.

$15 DIY Multisensor - Temperature, Humidity, Light, Motion, and RGB LED

This goes into setting up an AP with private WIFI access on DD-WRT

DD-WRT (Virtual)AP with guest and private WIFI access (on 2nd router)

NirSoft has a bunch of tools for windows.  Some are very niche and others are simply handy.  All are high quality.