Is a CdS photoresistor a good detector for green light?

[Rob Seastrom]

Hey folks,

I'm on the cusp of throwing together something quick and dirty (and
raspberry pi based probably; the price is right) that will talk to a
couple of sensors hanging over the "cycle complete" LEDs on our washer
and dryer and send appropriate text messages to a cell phone when
they're done.

I was thinking about a CdS photoresistor (they're making 'em *tiny*
these days!) with one leg hooked to Vcc, the other to a pull down
resistor to ground, with the connection between the two hooked to a
binary input pin of the Pi.  Kind of a quick and dirty "light
controlled voltage divider".  Should work for a high impedence pin on
the Pi with minimal fuss.

Tape the whole affair over the LED (maybe with a software controlled
LED stuck to the back so that it can be lit to not lose having an LED
on the front of the device when the cycle is done).

Only thing is, I'm not sure what the sensitivity of a typical CdS
photoresistor is in the green band, and LEDs aren't very broadband so
I can't get by on slop if this is a blind area for them.  Spec sheets?
Ha.  That's like trying to find a datasheet on a 2.2k gold band
resistor.  These things are buck-apiece commodities.

Can anyone shed some light (pun intended) on the receive passband of a
typical CdS photoresistor?

Thanks,

-r