How would I wire a motion sensor to a fluorescent light?
I found a few different models of the Defiant sensor.  It looks like they all contain an electronic switch, with some controls like timing and sensitivity.  

Of the models I found, some say they only work with incandescent bulbs, and some with incandescent or LED, but none claimed to be compatible with fluorescents.  One of the models that claimed to work with LED bulbs had customer feedback complaining about it not working with LED bulbs. So if you use it with fluorescents, be prepared to buy a replacement ballast if it works at all.

That said, the wiring would be as follows:


White is neutral and gets connected in common with the white leads of the feed and the light.  The feed would be a wire running back to the breaker panel.  If the white is already connected to the feed, just add the white fixture wire to it.
The models I saw had a bare or green wire, which is the ground wire and gets connected in common with the ground wire of the feed and the ground wire of the fixture.  My understanding is that if your sensor does not have a ground wire, it won't work with a fluorescent fixture (not 100% sure that is universal, or even what role it plays with the ballast, but I'll pass on that nugget for what it's worth).
Black is power into the sensor and is connected to the black wire of the feed.
Red is the power output (hot) from the sensor and gets connected to the black wire of the fixture.


If you find a similar sensor on the Home Depot web site, you can download the installation manual there.  It covers not only the wiring, but how to adjust and use the controls.