richard - they do/can contain algorithms and your first synerio is plausable.

http://www.kionix.com/accelerometers/kx022

however in cell phone, from my quick study of sensor hub we see a microprocessor-type that receives the data from the 5-7 onboard sensors and wil/can make decisions, as instructed by algorithms, on what to do next.

''Intel calls out for the sensor fusion algorithm to be embedded in the sensor hub and not in the CPU. While the CPU has more than enough processing power, according to Intel, constantly running the sensor algorithm would consume much more power than the sensor hub''

http://www.movea.com/news-and-media/in-the-news/446-semico-future-of-sensor-fusion-in-computing

it's complex

e