Regular readers of WikiTrend know that there is a huge trend among mobile hardware developers to create attachments that extend the usefulness of our phones. We have written about smartphone add-ons including breathalyzers, professional light meters, spy lenses, wind-speed meters, virtual reality attachments and much more. And now there's Scentee, a little device that plugs into a phone's audio jack and emits a scented spray on command. Now, instead of your phone notifying you by sound, you can program it to alert you smell whenever a call or text comes in. Or add scent to your alarm clock. While we are not sure how relevant this is to many people, but it is novel and reflects a growing trend by which people are adding devices to their devices.