Sarah Gregg (asker) Oct 13, 2017:

Thanks for your help, but in the end the client has decided to simply cut the words "a ventaglio". Guess that's the simplest way in the end!

Sarah Gregg (asker) Oct 11, 2017:

Sorry not to have closed the question sooner, but I'm still waiting for a reply from the client that could give us more information to decide the most appropriate term. Thanks for your patience.

Sarah Gregg (asker) Oct 8, 2017:

Thanks to you both for your suggestions. Given that there seems some doubt, I've asked the client for more explanation. I'll let you know the outcome.

philgoddard Oct 6, 2017:

This may be relevant "PIR occupancy sensors sense the difference in heat emitted by humans in motion from that of the background space. These sensors detect motion within a field of view that requires a line of sight; they cannot “see” through obstacles.

The sensor’s lens views its coverage area as a series of ***fan-shaped coverage zones***, with small gaps in between, and is most sensitive to motion that occurs between each zone (lateral to the sensor).
http://www.smsistemi.it/index.php?option=com_virtuemart&view...