littleBits i13 light sensor

My kid built a nightlight that only kicks on when the room gets dark, and the sensor handles that fade-in perfectly. It's surprisingly responsive to small changes in light, so covering it with a hand actually dims the circuit instead of just flipping it on.

I taped this sensor to my window and now my little circuit turns on automatically when the sun comes up. It responds smoothly as the light fades too, no flickering or lag. Easily my favorite Bit so far.