HN Distilled

Essential insights from Hacker News discussions

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

Original Article

Hacker News Discussion

Lid Close Detection Reliability

A significant portion of the discussion revolves around the reliability and implementation of lid close detection on laptops, with a notable contrast drawn between different manufacturers. Some users report positive experiences with specific brands, while others express frustration with inconsistent performance across various models.

  • "ramon156: And also it has a magnet to detect the lid being closed. People think this is over engineered, but I've never yet to see another brand that has a working closed lid detection"
  • "mouse_: Only ever had a Thinkpad lid close sensor fail once. Found my T60 heating up my backpack. Other than that, never been a problem. I've never once had a Dell/HP/Acer/Asus with a reliable lid close sensor. You can't trust those things."
  • "gruez: ??? I don't think I've seen a laptop that doesn't have closed lid detection. At the very least it's common enough that windows has a setting specifically for it: "
  • "Analemma_: With both Windows and Linux, it's always a luck-of-the-draw thing. Sometimes closing the lid works perfectly, sometimes you get a doofus manufacturer with lousy drivers, so 1 in 20 times you pull your laptop out of your bag and it's red hot with a drained battery."
  • "ufmace: It works fine, except for when it doesn't. Source: My macbook has drained its battery flat while closed in my bag dozens of times. Then it just stopped doing that on an OS update. I still have no idea why."
  • "bigyabai: Ironically, I had this issue with my Macbook more than my Windows and Linux machines combined."

Windows "Modern Standby" vs. S3 Sleep

The discussion frequently points to Microsoft's "Modern Standby" (formerly "connected standby") as a primary cause for laptops failing to sleep correctly, leading to battery drain and overheating. This is contrasted with the more traditional S3 sleep state, which is seen as more reliable, especially for Linux compatibility.

  • "trenchpilgrim: If you're talking about laptops waking up inside backpacks- that's due to the terrible implementation of "Windows Modern Standby" that has ruined every laptop except Macbooks and Framework. (Framework still implements legacy S3 standby to improve compatibility with Linux.)"
  • "zargon: That’s what Modern Standby does."
  • "gruez: That's due to "connected standby", which is to have laptops behave more like a phone when in sleep. This is in contrast to S3 sleep, which basically halts all activity. Sounds all good in theory, but as soon as you allow code to be run while in sleep, it's easy for some runaway app (OS or third party) to eat through your battery even while your laptop is "sleeping". Worse is that there's no way to force sleep, so your only choice is hibernate, which is even worse than S3 sleep before."
  • "cosmic_cheese: “Modern standby” is indeed the culprit in many cases, maybe even the primary one these days, but to my understanding it can still be a crapshoot on laptops that support S3 sleep since it’s up to the OS to detect that the lid has been closed and put the machine to sleep. This has been a problem for a very long time, since well before it became cool to pretend to be a smartphone and not actually sleep the machine."
  • "com2kid: For a long time (years) there was a bug in Firefox that'd prevent a Windows machine from going to sleep if webgl content was loaded in any FF tab. So anyway that killed one of my laptop's batteries. So much for supporting Internet freedoms... Windows comes with a utility that'll tell you what process denied a sleep request, super useful."
  • "I've actually ran into MacBooks not sleeping a few times, but it is much rarer. It is unfortunate because back on the mid 2000s windows had the best functioning sleep code, but then they tried to catch up with iPad's # instant on and chasing perfection led to the current mess."
  • "toxik: Macs these days wake up regularly as I understand it. My MacBook's battery discharges decently fast even when the lid is shut"

Underlying Causes of Sleep/Wake Issues

Beyond "Modern Standby," users speculate on various other factors contributing to laptops waking unexpectedly or failing to sleep properly. These include:

  • Software/Driver Issues: The overall reliability is often attributed to the quality of drivers and OS implementation.
    • "cosmic_cheese: There’s also wake on LAN which if enabled can rouse the machine from sleep after it’s successfully entered a sleep state."
    • "com2kid: <...> I've actually ran into MacBooks not sleeping a few times, but it is much rarer."
    • "mort96: What makes you think that these issues you describe (which I've experienced too, FWIW) are problems related to the sensor rather than the OS or drivers?"
    • "CamouflagedKiwi: I don't think this is about the hardware driver detection of the lid closing. Lid events are a first-class thing in ACPI and I've never seen a laptop that didn't have one, or any real evidence that one didn't do the thing. Much more likely is that the OS was prevented from going to sleep by some badly behaved process, or got woken up by another thing like allowing USB to wake it from sleep, where even touching the mouse can wake it - with some laptop equivalent like a ghost touchpad touch or whatever."
  • Third-Party Software: Company-installed spyware or specific applications (like Firefox with WebGL) can interfere with sleep states.
    • "geoffeg: I've also found my work MacBook Pro heating up my backpack sleeve a number of times because it didn't properly go to sleep. Likely culprit is some "security" spyware the company installs."
    • "com2kid: For a long time (years) there was a bug in Firefox that'd prevent a Windows machine from going to sleep if webgl content was loaded in any FF tab."
  • Hardware Design/Sensor Interaction: Even when sensors are present, their interaction with other hardware or their specific implementation can cause issues.
    • "BuildTheRobots: The magnets work too well. Having one Thinkpad Yoga sat on top of another closed Yoga tricks the sensor into thinking it's in tablet mode and it disables the keyboard. I only lost 30min or so trying to work out what was happening..."
    • "cosmic_cheese: The old Intel models were hit or miss, but with the M-series models I’ve never had problems with MacBooks not going to sleep when the lid is shut and staying that way so long as wake on LAN is disabled (or disabled on battery). That setting does need to be off though, with it on I did observe occasional misbehavior."

The Role and Cost-Effectiveness of Hinge Angle Sensors

A significant portion of the conversation is dedicated to the potential utility and cost of hinge angle sensors in MacBooks and other devices. Users discuss the "free" nature of obtaining angle data from existing Hall effect sensors, the reasons Apple might integrate such sensors (thermal control, warranty, Desk View), and the feasibility of similar features on other platforms.

  • "crazygringo: I wonder why? Presumably this information doesn't come for free, and Apple spends money to put this sensor in. Is it a backup if the magnet for closed lid detection fails? Is it some kind of input for the brightness sensor or True Tone? Is it for warranty investigation, that if the hinge breaks they can figure out if it was physically pushed too far, or was repeatedly slammed open and shut like a toy?"
  • "rossant: Wild idea: if the goal is to wake from sleep as quickly as possible when opening the lid, could receiving a signal as soon as the user starts lifting the screen save a few hundred milliseconds? I might be way off though."
  • "avianlyric: The info probably does come for free. The magnets along the top edge of the screen... those magnets are just there to provide the latching effect when the screen is closed, so it doesn’t open accidentally. The sensor used for detecting if the lid is closed is an “angle” sensor, although really it’s an Hall effect sensor and a magnet in the hinge. If you have a Hall effect sensor, getting angle data from it is pretty much free..."
  • "postalcoder: It’s likely there to support Desk View. Desk View presents the items on your desk in a geometrically correct, top-down view. Knowing the angle of the display is very helpful when applying keystone correction."
  • "estimator7292: We've been using Hall effect sensors for lid close detection for a long, long time. My thinkpad from 2013 has it halfway down one edge. If you simply move the sensor (that is already a requirement) closer to the hinge, you can infer angle based on the Hall sensor for free. You can even get special sensors that specifically measure the magnetic field orientation for the same price as the simple type."
  • "macNchz: Once upon a time Mac laptops used reed switches to detect closed lids, and they were a common point of failure, presumably since they contained moving parts."
  • "seanalltogether: My best guess is it's related to thermal control. The vents on macbooks are right under the hinge, and the vents are blocked and opened to different degrees based on the angle of the lid."
  • "nostrademons: A lot of foldables have a hinge angle sensor - it's actually a public API in Android, and robust enough that we use it to detect whether a device is a foldable:"
  • "chmod775: Chances are there's an accelerometer in the screen and one in the base."
  • "whitehexagon: Great! so they already know that I've been squinting at a 42deg gap trying to use my old MBP. The year with the faulty designed screen connector which was only covered for replacement on certain models, not mine. I wonder if that is why they added this, to check for 'holding the lid wrong'."
  • "wslh: Is this part of telemetry?"
  • "nixosbestos: No, it's really not [subjective]. You know, evidenced by the fact you have to manually post every fking reply link, individually, for the non-siccophants among us to be able to read it?"

Discussion on Link Sharing and Platform Preferences

A tangential but active thread of conversation concerns the sharing of links, particularly the preference for platforms like Mastodon over Xitter (Twitter) due to perceived better accessibility, lack of ads, and privacy concerns.

  • "deathanatos: This post was also made (by the same person, it seems) on Mastodon — which has the added benefit of not being X, not requiring cookies, and has more information than the tweet, including a follow-up "theremin" hinge."
  • "altairprime: Good catch! You can email the mods to ask the link be changed; use the footer contact link."
  • "Wowfunhappy: If a mod sees this, can we please get TFA changed? Both sources are equally authoritative in this case so we may as well use the nicer one."
  • "josephcsible: "nicer" is too subjective IMO. Both being equally authoritative is an argument to keep the one the original submitter used."
  • "leephillips: I would change it if I could."
  • "freehorse: Mastodon is more accessible though. And I do not even use mastodon."
  • "nixosbestos: > nicer" is too subjective IMO. No, it's really not. You know, evidenced by the fact you have to manually post every fking reply link, individually, for the non-siccophants among us to be able to read it?"
  • "edgineer: Just so you know, you can /s/twitter.com/nitter.net/ the URL to see replies without logging in"
  • "estimator7292: You can see the thread and its replies, there's no ads, trackers, popovers, spam bots, AI ads. You simply see what the author posted and people's reactions. It also doesn't load 400MB of JavaScript or whatever."
  • "EA-3167: This is exactly why I avoid things like Mastodon as well, because the problem isn't who controls the format, it's the format itself. Who controls the format sure doesn't help, but if you imagine Mastodon becoming as universally adopted as Twitter and seriously don't think it would be a massive mess, then I envy your optimism."
  • "wlesieutre: I can't see it, and if I click on @samhenrigold's profile I get a random selection of things from this July and last October instead of recent posts . It's really not a useful platform for publicly sharing information anymore."

Creative Sound Design for Laptop Actions

A smaller thread explores creative ideas for sound effects related to laptop lid actions and other interactions, ranging from common household sounds to musical elements.

  • "mouse_: Close/open sound font ideas Jacket zipper C Major scale Slide whistle Washboard Airlock Vinyl record scratch"
  • "oever: trombone/piano/violin glissando falling and crash sound ratcheting ring spanner passing train/helicopter/car heavy door (safe/cave) theremin"
  • "anotherhue: Creaky dungeon door surely?"
  • "bmcahren: Missed a huge opportunity to play the sound of a monstrous wooden door sound when the lid closes. Looking forward to the update!"
  • "HPsquared: Venjent has some amazing door-based tracks. Edit: not forgetting the classic Miles Davis door: "
  • "latexr: For fun and whimsy in a world populated by too many exploitative apps. And because the author has a lot of free time (their words)."
  • "Finnucane: this just makes me miss the old Mac OS that let you add sound effects to anything. I_dream_of_Geni: IKR? The good old days..."