The Light Theremin is a simple to build instrument that uses light and shadows to create sound. The theremin circuit used nomally for these insruments are quite complex, this one however is as simple as a 555 Timer IC and some basic components from your scrap box. so with out any more delay...Lets get started!
Your materials list is really quite short. You will need the following parts...
Please note that the quantity of each part is in the [ ].
-555 Timer IC 
-100uf Electrolytic Capacitor 
-1.0uf Disk Capacitor (Marked "104") 
-Photo Resistors 
-1K Resistor (colours: Brown, Black, Red, Gold) 
-a Switch 
-9v battery 
-A speaker 
-A IC proto board to keep it all nice and tidy 
-Some machine screws and nuts to hold down the board (optional)