I spent the past 6 years restoring and upgrading the 2 flights of stairs in my almost 100 years old house in my off time, taking into them into the 21st century while I was at it. The result is a standalone extensible system that supports an unlimited number of sensors and can light up to 256 cheap LED strips on a setup that can run completely off of a simple USB power bank for days and costs under about €40 in parts.