Turning Off the LCD at Night

I like the brightness level of the LCD I'm using on my vivarium project; but, it was giving the living room a distinct glow at night.  It turned out to be a quick fix to turn the LCD off when the ambient light level was low.  I ordered a Photocell from Adafruit and followed the tutorial on wiring it up along with a pull-down resistor (the concept of pull-down and pull-up resistors is something I'm just finally getting my head around).

Photocell and 10K Pulldown Resistor on Pin A3

Then I added a simple check in the loop to test the brightness level:
For my environment, simply splitting the range in half has worked well.