My third ChrisLights project is something I've been meaning to try for quite some time: building an interactive staircase.
The main blocker I always faced was the task of accurately sensing where a person is on the staircase. I'd always imagined using an ultrasonic sensor for this, but the results were far too erratic when using them in the confined space around my staircase.
After realising that I could use an array of lasers and photoresistors instead, I ordered the components and started building.
It took a lot of work - especially on the wiring and soldering side of things - but I was really happy with the end result and the response I got from the video blew me away! I reached the #1 spot on /r/arduino with over 600 upvotes and 11K views, got over 900 upvotes on 9gag, and I was retweeted by the official Arduino twitter.
You can see the results (and more of an explanation) in the video below:
I'm busy working on a Part 2 video, which will add more sophisticated effects to the staircase.