Inspiration for this project came from a MakeZine project: http://makezine.com/projects/high-speed-splash-photography-with-arduino/
Using a lightstand as a base, this Lego build was positioned above a glass bowl filled with water. An Arduino Uno board controlled the camera shutter, a flash, and the Lego ‘Dropper’. The time delay between the drop and the flash trigger was entered into a laptop. The results can be seen at: https://flic.kr/s/aHskhKLsh9. A video of the rig in action is shown below.