I have four projects.
I created a system called "JogThem" based on Google services to send notifications. This is the kind of notification that websites or youtub use. It worked, but I haven't deployed it or made it public. I completed this several years ago & have mostly forgotten how it works.
An arduino control for programmable LEDs. This is for lighting inside models of buildings with different rooms have slighly different color lights The lights change subtly to suggest movement and they come on an off at various times to suggest entering and leaving rooms.
An Arduino controlled sound system which detects control pulses sent by a distant digital command control system (used for train controls) The system plays recorded sounds based on which kind of commands are issued.
I am likely to describe 2 & 3 in videos on YouTube at some time.
This is a plan for the future of spreedsheets making use of structured data instead of the conventional 2 dimensional array.