They call it "calibration" when it's presumably nothing more than writing a serial number to an EEPROM somewhere. See also the related story of sabotaging iPad screens to work but subtly degrade when the serials don't match, and cameras that only semi-work when swapped (with genuine original Apple parts). This type of pathological lying that Apple loves to do is why I'll never buy or recommend to others any of their products.
Interesting but that proves the point even more --- it's hardly "calibration" when it effectively does nothing more than write constants to the EEPROM. They certainly have enough processing power in the machine to do that automatically too without needing anything more, but instead they make everyone go through a whole song-and-dance to do this trivial process; which doesn't even require Apple's involvement.
"Set the angle to 0 (closed) and press Enter. Open 10 degrees and press Enter. Repeat for every 10 degrees from 0 to 170" would be an example of actual calibration.
That's not something that needs to be measured externally.
Also, one wonders just how horrible their production tolerances must be if something like this even needs that sort of calibration in the first place. No other company does this. Nonetheless, even if one accepts this bizarre excuse at face value, it doesn't take a genius to realise that the firmware can "self-calibrate" trivially: If the EEPROM in the sensor is uninitialised, then it just needs to record the max/min value the first time it's closed, and save that as the "lid closed" point.
The only plausible explanation for doing all this extra work is that this isn't merely incompetence; it's intentional malice. Given how much Apple spends on lobbying and other hostile activities, this is not surprising.
It wouldn’t matter… just tell the user to close and open the lid before pressing enter again, and get the maximum (or minimum) value as the lid being close all the way.
Exactly my thought, but this might not be precise enough in low light conditions? So maybe best used as a fail safe (if camera is lit don't calibrate even if the user pressed confirmed)
It does actually perform a security function. The lid angle sensor is used to know when the device is open or closed, and when closed, it physically disconnects the microphone. If you were to be able to recalibrate it at any time, you would leave your device vulnerable to having the microphone enabled when the lid is closed. You can argue whether that justifies the practice, but it's not as simple as just burning the EEPROM serial number in that tells it to turn the display on or off. It defends the user against an attack vector.
From that perspective making it one-time programmable is not unreasonable.
Though it could be simpler if it was something like a magnet on the lid that activates a magnetic switch on the bottom part (and it would be harder to have a false negative result). But Apple is going to Apple
Yes, it could be done with a Hall effect sensor or something like they used to. The cool thing about this approach is they actually use a different angle to turn the screen off as you close the lid than they do for turning it on when you open the lid, to create a better experience. Since it is a security feature, then the "open" vs "closed" state should use the same source of truth. So it's a trade-off of complexity and experience.
Apple even makes a suitable one themselves... but the point is that a calibration procedure involves adjustment and measurement, and not merely reading some data from the sensor and writing it back. If Apple weren't deliberately trying to be hostile and sneaky, they would not have bothered with this roundabout, obfuscated process which no doubt increases their production cost too.
https://news.ycombinator.com/item?id=24955071
https://news.ycombinator.com/item?id=36926276