I have some years posted links to different Christmas lights project on the net. This year is no different. Here is the first one on this topic.
Christmas light controller is its own percussion section article tells that Jason and his father took advantage of a week off of work over Thanksgiving to design and build a Christmas light decoration that can flash fancy patterns. He calls this Arduino Uno powered Christmas tree Uno Christmas Tree. The main controller is based on Arduino UNO and a 16 channel mechanical relay board. The project builder aims to use solid state relays to be faster and less chance of a relay sticking.
Earlier postings on Christmas lights: