Interactive Town Play Mat Project

We have this IKEA town play mat that my kids like to drive toy vehicles and other things on. My son also has a Thomas the Train track set and sometimes he incorporates a track layout around the town. Like a true bricoleur, he uses whatever he can find to create crossing guards and such to mark the railroad crossings.

My idea is to use Arduinos and other components to add some interactivity and lights to this play mat. I have three primary features that I would like to accomplish:

1. Set up one or two working intersection signal lights that will alternately cycle through green, yellow, and red lights in a timed sequence.
2. Build a working railroad crossing signal that will detect when a toy train is approaching and flash red warning lights and maybe sound a warning bell.
3. Add a series of "street lights" that will automatically turn on when the ambient light level gets low

Subsequent posts will detail the process of building this project, from finding the components to programming the Arduino Sketch to the final layout of the play mat.