Doing the rounds today on the Interwebs are a series of videos from Bill Hammack, 'The Engineer Guy', looking at how a number of things work - who doesn't love this sort of common man explanation of some really clever science and engineering? Embedded below are three of the most relevant videos, covering smartphone accelerometers, LCD displays and overall design constraints.

Here's the 'how it works' video on smartphone accelerometers, you'll love the clever way a microscopic cantilevered beam of silicon is created in the heart of the accelerometer:

And, while we're here, here's Bill's take on how LCD displays work, albeit on a larger scale than smartphones (and note that many phones now use AMOLED tech, which is subtly different again). 

Finally, here's a (slightly dated) look at the main constraints designers have to face in designing 'cellphones':

Well presented content throughout.

More videos like these on Bill's YouTube channel.