The MacBook has a sensor that knows the exact angle of the screen hinge

Posted by leephillips 9/7/2025

The MacBook has a sensor that knows the exact angle of the screen hinge(twitter.com)

Alts: https://hachyderm.io/@samhenrigold/115159295473019599, https://bsky.app/profile/samhenri.gold/post/3ly7252lx422d

Theremin Mode: https://twitter.com/samhenrigold/status/1964464940049453153

Github: https://github.com/samhenrigold/LidAngleSensor

1023 points | 489 commentspage 4

hyperhello 9/7/2025|

Is there a downloadable source for this? I’d love to add it.

latexr 9/7/2025|

https://github.com/samhenrigold/LidAngleSensor

fwip 9/7/2025||

My understanding is that this sensor is used to help adjust speaker behavior for better sound, but I can't find a link to support that.

nickdothutton 9/7/2025||

MacBook Protractor

nodesocket 9/8/2025||

Seems like they should expose it, perhaps done for security reasons. I can in-vision some interesting apps using the angle.

gjsman-1000 9/7/2025||

The Nintendo Switch 2 according to Welcome Tour can also detect hinge angle. Unclear if this is a sensor or clever math though.

danielbln 9/7/2025|

I bet it's just the built-in gyro.

a-dub 9/7/2025||

my guess: probably there to support the camera system and depth camera.

although unless there's some sort of angle measurement with respect to the ground in the base, i'm not sure what it would be useful for. maybe to provide continuity for the depth camera when the lid angle is changing (without heavy duty estimation calculations).

comrade1234 9/7/2025||

Is it the angle of the hinge or the angle of the screen? I assume the latter... my laptop is rarely on a level surface.

Sharlin 9/7/2025|

At first I wondered why you'd assume the latter – certainly something like a tiny rotary encoder is a simpler lower-tech solution than a MEMS inclinometer. But these days I'm not actually so sure.

joezydeco 9/8/2025|||

They're using a pretty nifty differential Hall magnetic encoder, like this one:

https://www.novosns.com/en/hall-angle-sensor-4010

There's a fun Hackaday video using the same type of part in a rotary knob + LCD control.

https://www.youtube.com/watch?v=zIrAe23f8sg

Sharlin 9/9/2025||

Cool, thanks!

jeffbee 9/7/2025|||

Without checking the catalog, I would assume that a MEMS inclinometer is much cheaper in 2025 than an absolute position encoder.

Edit: catalog confirms.

Sharlin 9/9/2025||

Thanks. Clearly my intuition was out of date.

chipsrafferty 9/7/2025||

Someone should make a video game where you have to jerk the hinge back and forth for basic movement

batrat 9/8/2025||

How is this useful? I don't get it? Is not a touchscreen, doesn't fold...

chmod775 9/7/2025|

Chances are there's an accelerometer in the screen and one in the base.

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