These instructions are to create a box with a light sensor and buzzer that will play a single-note-at-a-time tune when a shadow is cast across it...such as from a passer by. This is done using an Arduino.
Step 1: Gather the materials
You should be able to find most of this at radio shack, arbitrary electronic parts store, arbitrary tool stores, and/or walmart.
The 6.4Mohm resistor should probably be changed depending on your photoresistor. Choose a resistor about halfway between the usual light and dark values of your photoresistor.
*5" x 2.5" x 2" project box with metal insert. (like from radio shack)
*9V battery clip
* a radioshack piezolectric buzzer (no internal oscilator)
* 1x3 and 1x6 bits of pin header (http://en.wikipedia.org/wiki/Pin_header)
* 9V battery
* photoresistor (from radio shack, came in a variety pack)
* single pole double throw bat style switch (used and single pole single throw) (as in picture)
* resistors: 112ohm, 6.4Mohm.
* diode (1N4002) (may substitute some other power diode)
* stranded wire
* shrink tubing for just-in-case insulation since the parts are just freely connected.
* 2 sets of #2 machine screw and nut. 1/2" long.
* soldering iron and solder
* drill and assorted bits
* super glue
* a bit of pillow stuffing or something.