eliminates the need for delicate optical components and expensive detectors by using a “virtual” light-emitting diode (LED) source and inexpensive photodiode detectors
the current supplied to the LEDs is varied through a sequence of steps to vary the frequency of the light produced by the emitter
one prototype source incorporates 34 emitters that are fired through 25 current steps in a sequence that is repeated four times; in effect, a single less-than-one-second scan paints 34 × 25 × 4 = 3400 flashes of light onto the sample
Recent testing on plastic sample bags containing a variety of similar-looking white powders demonstrated that the SPM ChromaID method was able to distinguish between flea powder, household cleaner, ground Tums, Splenda, baby powder, and cornstarch, to name a few
The Internet of Things is really an Internet of Sensors. It was Kevin Ashton of RFID fame who first popularized the phrase Internet of Things. But the way he and others explored the idea made it clear that the key element of this Internet of Things was that things were going to be individually addressable on the network.
With enough of the right sensors in my life, the sensors can flexibly identify the things in my environment and provide a very efficient means of addressing them