I had to run by Radio Shack yesterday and out of habit pulled open the drawer with the sensors and noticed that the Parallax TSL230R is on clearance for $1.90-ish. It is a fairly cheap sensor at $5, but for less than two bucks, I think it is well worth picking up.
For anyone who doesn’t know about that sensor, it is a Light to Frequency Converter:(from datasheet)
The Texas Advanced Optical Systems (TAOS) TSL230R measures light intensity using an array of photodiodes and outputs a square wave whose frequency is proportional to light intensity striking the surface of the chip.
? High-resolution conversion of light intensity to frequency with no external components
? Programmable for three sensitivity levels
? Convenient 8-pin 0.1” DIP package
? 3.3 V or 5 V operation
? Absolute output frequency tolerance of +/- 20%
? Easy to interface directly with microcontrollers
? Flash detection
? Cloud detection
? Laser beam interruption detector
I just thought someone here might find it useful to have one or two of these.