4 ms·

There's nothing that requires a microcontroller to be active during power-down to handle the issues you describe: For transit passes and IDs, there need to be

There's nothing that requires a microcontroller to be active during power-down to handle the issues you describe: For transit passes and IDs, there need to be non-phone-based ways of handling that issue. It's equally possible to lose / have your phone stolen. Talk to the station agent, or have the police look up your license by name / address. There's no need for a continuously-running microcontroller to read the power button. It's perfectly possible to have the power button feed power directly from the battery to a bootstrap power management IC, which then takes over supplying power to the main processor. USB connections supply power, so it's easy to implement having the presence of power on the USB port boot the phone.

avianlyric 5y ago
> For transit passes It’s interesting, here in the U.K. you have a legal obligation to present a valid ticket upon demand for any train you travel on. Failure to do so for any reason (including my phone died, or I dropped the ticket) is a criminal offence (and I mean criminal, not civil) punishable by a prison sentence. Some ticket conductors at the end of a long shift hearing endless excuses about why someone doesn’t have a valid ticket really aren’t interested in negotiating. They’re quite happy to enforce the law, and make your life a living hell in the process. Personally I much prefer it if the transit pass on my phone keeps working after it dies. The alternative is very… inconvenient.
- fy20 5y ago
  Meh this sounds like scare mongering. If someone is tired at the end of a long shift, what do you think they are going to want to do more? a) spend 15 minutes writing up a ticket, and possibly waiting for the police to arrive before handing you over to them b) take you to the back office and let you sit for 5 minutes while your phone charges Nobody is going to send you to prison for the first offence of not having a ticket (a physical ticket could be lost or damaged to a point where it is unreadable too). They would probably issue a fine, but you could appeal that. Buying a digital ticket you'd have a digital paper trail showing you bought it - which you wouldn't if you bought a paper ticket.
  - avianlyric 5y ago
    > spend 15 minutes writing up a ticket, and possibly waiting for the police to arrive before handing you over to them > take you to the back office and let you sit for 5 minutes while your phone charges Your on a train. There’s no back office, and neither of you are going anywhere in a hurry while it’s moving. They just ask the police to meet them at the next station and hand you over. > Nobody is going to send you to prison for the first offence of not having a ticket Prison sentence, probably not, £200 fine and a criminal record, not unlikely. I certainly know people who have found themselves on the wrong side of a TfL ticket conductor, and then found themselves in front of a judge. Train ticket enforcement is a surprisingly disproportionate part of British law.
- josephcsible 5y ago
  So if while you're on a train, someone steals your paper ticket, you're the one who goes to prison?
- KingMachiavelli 5y ago
  Wait... is this currently a thing? Does the transit pass keep working after the phone is off? If that's the case then it must really just be keeping a single unique identifier available and broadcasting it. Also the easy fix for such an issue is to just poweroff the phone when it has ~5% of the phone power left which most phones already do. Instead of broadcasting its location, transit ID all the time it could just do it when you hold the power button down or something... it would last longer anyway.
  - numpad0 5y ago
    Supposedly: https://support.apple.com/guide/security/express-cards-with-power-reserve-sec90cd29d1f/web https://support.apple.com/guide/security/express-cards-with-...
  - avianlyric 5y ago
    Yeah, the phone hand off the express transit cards crypto keys to the NFC chip used for Apple Pay. Allowing the chip to authorise transactions without the CPU getting involved.

avianlyric 5y ago

> For transit passes It’s interesting, here in the U.K. you have a legal obligation to present a valid ticket upon demand for any train you travel on. Failure to do so for any reason (including my phone died, or I dropped the ticket) is a criminal offence (and I mean criminal, not civil) punishable by a prison sentence. Some ticket conductors at the end of a long shift hearing endless excuses about why someone doesn’t have a valid ticket really aren’t interested in negotiating. They’re quite happy to enforce the law, and make your life a living hell in the process. Personally I much prefer it if the transit pass on my phone keeps working after it dies. The alternative is very… inconvenient.

fy20 5y ago
Meh this sounds like scare mongering. If someone is tired at the end of a long shift, what do you think they are going to want to do more? a) spend 15 minutes writing up a ticket, and possibly waiting for the police to arrive before handing you over to them b) take you to the back office and let you sit for 5 minutes while your phone charges Nobody is going to send you to prison for the first offence of not having a ticket (a physical ticket could be lost or damaged to a point where it is unreadable too). They would probably issue a fine, but you could appeal that. Buying a digital ticket you'd have a digital paper trail showing you bought it - which you wouldn't if you bought a paper ticket.
- avianlyric 5y ago
  > spend 15 minutes writing up a ticket, and possibly waiting for the police to arrive before handing you over to them > take you to the back office and let you sit for 5 minutes while your phone charges Your on a train. There’s no back office, and neither of you are going anywhere in a hurry while it’s moving. They just ask the police to meet them at the next station and hand you over. > Nobody is going to send you to prison for the first offence of not having a ticket Prison sentence, probably not, £200 fine and a criminal record, not unlikely. I certainly know people who have found themselves on the wrong side of a TfL ticket conductor, and then found themselves in front of a judge. Train ticket enforcement is a surprisingly disproportionate part of British law.
josephcsible 5y ago
So if while you're on a train, someone steals your paper ticket, you're the one who goes to prison?
KingMachiavelli 5y ago
Wait... is this currently a thing? Does the transit pass keep working after the phone is off? If that's the case then it must really just be keeping a single unique identifier available and broadcasting it. Also the easy fix for such an issue is to just poweroff the phone when it has ~5% of the phone power left which most phones already do. Instead of broadcasting its location, transit ID all the time it could just do it when you hold the power button down or something... it would last longer anyway.
- numpad0 5y ago
  Supposedly: https://support.apple.com/guide/security/express-cards-with-power-reserve-sec90cd29d1f/web https://support.apple.com/guide/security/express-cards-with-...
- avianlyric 5y ago
  Yeah, the phone hand off the express transit cards crypto keys to the NFC chip used for Apple Pay. Allowing the chip to authorise transactions without the CPU getting involved.