Once upon a time, 2 girls greatly enjoyed walking in the rain with umbrellas.
They decided the enjoyment of this experience could be maximized by building their own pressure-activated web of LEDs to install under their umbrella.
Thus, with the help of an Arduino, some 4051 multiplexers, a lot of wire and a lot of solder, they set off on their path to success.
Step 1: Materials List
We used the following materials:
1 Arduino Uno R3 microcontroller
1 9 V Battery
24 yellow LEDs (we advise that you use one with diffused light and a wide viewing angle, otherwise the size and color is up to you)
8 piezo sensor disks (we specifically ordered these from sparkfun: http://www.sparkfun.com/products/10293, though they are a bit fragile. You might want to look for something different.)
2 4051 multiplexers/demultiplexers
8 1 MΩ resistors (to be in parallel with the piezo sensors)
8 10 Ω resistors (to be in series with the LED strings)
LOTS of wire
LOTS of solder
Hot glue/hot glue gun