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I think I finally figured out what it was.... the screen gets turned on whenever the ambient light increases dramatically, like turning on the light in a dark room. I had no idea the MacBook had a light sensor... Maybe the infrared port? The iSight is definitely off. I have Input Remapper installed, and it mentions something about a light sensor, but I thought that was the Pro only.
 
I think I finally figured out what it was.... the screen gets turned on whenever the ambient light increases dramatically, like turning on the light in a dark room. I had no idea the MacBook had a light sensor... Maybe the infrared port? The iSight is definitely off. I have Input Remapper installed, and it mentions something about a light sensor, but I thought that was the Pro only.

The ambient light sensor is located just next to the iSight.
 
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