Aaackshually, the Sudden Motion Sensor was introduced on 2005 in the PowerBook G4, and continued through the intel MacBooks with hard drives.

While officially undocumented, people figured out how to access it back then, with novel uses like smacking your MacBook to change spaces (virtual desktops) or swinging the Mac around to make lightsaber noises.

- https://www.youtube.com/watch?v=6uvQTTPr9Rw

- https://osxdaily.com/2006/12/06/macsaber-turn-your-mac-into-...

(I should know, I was in university back then and swung my Mac around like an idiot, lol.)

On the first Retina MacBook Pro 15" in 2012, and moving forward with all MacBooks that were SSD-only, they removed the SMS as it was not needed.

To my knowledge, this is the first time we're hearing that Apple Silicon machines have an accelerometer on the SoC, officially or otherwise. It's also certainly not branded or marketed as the SMS was. (https://support.apple.com/en-us/100871)

Happy to be corrected on this!

In 2022 "a little birdy pointed out an accelerometer" to iFixit on their teardown of an M2 MBA: https://www.ifixit.com/News/62674/m2-macbook-air-teardown-ap...

They could not figure out what it was for.

Ars Technica commenters at the time believed it was to record drops so Apple repair teams could rebuff requests :)

I think there's some sort of motion sickness reducing feature in MacOS Tahoe which would require an accelerometer.