I made a Hot Wheels car finish line for my son. Naturally the Arduino controlled sensors needed to be connected to my Laptop running a Processing sketch. “Winner, Lane Two!”
All code and circuit is included in the write-up here:
I am going to be developing this into a wireless version, using Processing for Android. Inspired by “Hot Wheels ID”, the new augmented reality Hot Wheels product.
Just an FYI - Suggest using photo transistors/diodes for your sensors instead of photo resistors. Photo resistors typically have a slow reaction time which is not good when measuring times to the millisecond or less.