This is a demo of a basic light sensor circuit. In this example, I'm using 3 photoresistors concealed under a semi-transparent cloth. At the beginning of the trick a chalice covers each photoresistor. When a chalice is lifted, light activates the underlying sensor. The corresponding LED is lit up and the magician can identify the chalice.
By Stacey Kuznetsov, email@example.com
Human Computer Interaction Institute (HCII)
Carnegie Mellon University
Starring Jen Marlow, Iris Howley, Stephen Oney
For Making Things Interactive Spring '09