a link in:

https://markhilliardatelier-blog.com/category/water-drop-photography/

But the time machine's website is no more there.

https://www.bmumford.com/photo/

My small device is similar to "The time machine". They are both intervalometers. His intervalometer controls the releasing time of water drops (two and more drops), mine controls the time between the start of the water drop and the end of water drop bouncing back.