I wanted to make a useful Christmas present for my mother-in-law. For exercise she likes to use her Gubli under the desk elliptical machine. I wanted to simulate her walking around a track as she exercised. I purchased a magnetic switch from Adafruit and asked my husband to design a 3D printed bracket to hold it to the exercise machine. I then programmed an Arduino to read the inputs from the magnetic switch and move a stepper motor and light a NeoPixel ring. I only had the Beta version ready by Christmas but just finshed the final version housing all of the electronics in a wooden box that is glued to the top of the exercise machine. It works great!
Grandma’s Arduino Avatar YouTube video