
What's up with the INFRARED cameras?
The Big Bang Theory Season 4, Episode 18

Now, inside we've got motion detectors,
INFRARED sensors...
The Big Bang Theory Season 3, Episode 13

The optics are great.
It's got INFRARED technology.
The Big Bang Theory Season 6, Episode 21

Run an INFRARED repeater,
photocell here, emitter here, easy-peasy.
The Big Bang Theory Season 1, Episode 2