One of the things I've noticed during my 7-year tenure at the magazine is how sensors are increasingly used to provide machines (and us) with situational awareness. It's fascinating to see how they smooth our way: Laptop screens that adjust the backlighting appropriately based on the level of ambient light. Seriously high-tech shoes capable of distinguishing between walking, running, or jumping on soft or hard ground and adjusting the level of cushioning in response (if you go to Adidas' Web site you can see a Flash movie showing how the shoe works). Cars with active stability control systems to prevent rollovers during sharp turns. Toasters that sense the color of the toast so they know when to stop.
Let's talk about the navigation sensors—magnetic compasses, inertial measurement units, GPS receivers and the like—coupled with other location systems such as RFID and wireless networks such as WiFi, ZigBee, or others. We're starting to get machines that know (sort of) where they are and, possibly more importantly, can report to us where they are and what's going on. Off the top of my head I can think of at least four applications I've heard of: tracking portable medical devices in a hospital, perimeter monitoring for various security uses, tracking cargo in containers and on trucks, and mobile robots in their various military and commercial configurations. If you know of other examples, let me know!
Do you want to know the part that kills me about all this? It's the fact that the better the sensor does its job, the more invisible it is. People exposed to these smarter products and machines see that they're easier to use on the macro level but they don't necessarily appreciate the clever little miracles of engineering that make it possible.