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posted by hubie on Monday January 29, @06:59PM   Printer-friendly
from the flushed-with-success dept.

Developer Hugo Landau has hacked a train's restroom door, based on the model found in the UK's Class 800 train:

Of course, there is a reason for the separation of the closing and locking functions, but not the opening and unlocking functions: it avoids a Denial of Service attack where someone can just press "close" and then jump out before the door closes. If the interior "close" button automatically locked the door, this would result in the toilet becoming permanently inaccessible.

The problem with this design is that most people don't understand state machines, and this design confused a lot of people who were unable to lock the door correctly, or believed they'd locked the door when they hadn't.

The result is a denial of service, being able to lock the door from the inside while no one is actually inside to subsequently unlock the door again.


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  • (Score: 1, Flamebait) by crafoo on Monday January 29, @07:12PM (2 children)

    by crafoo (6639) on Monday January 29, @07:12PM (#1342320)

    If you're going to continue to import 85 IQ laborers to suppress wages in your Western countries, you are going to have to begin to design the environment for 85 IQ farmhands. No lights, no state machines. Just a knob and a sliding latch. These people can't change an air filter in their car. They can't keep their kids from pulling pots of boiling water down on their heads. They barely understand the concept of time and a future version of themselves based on their decisions. Things will have to change.

    • (Score: 3, Interesting) by JoeMerchant on Monday January 29, @07:27PM (1 child)

      by JoeMerchant (3937) on Monday January 29, @07:27PM (#1342322)

      >They can't keep their kids from pulling pots of boiling water down on their heads.

      Funny (sad) memory from a (IQ considerably higher than 85) friend:

      When JFK was shot, all the adults were distraught, clustered around the television in the living room. Mom had forgotten she was boiling water on the stove until three year old Jenny pulled the pot down on her head.

      --
      🌻🌻 [google.com]
  • (Score: 2) by Rosco P. Coltrane on Monday January 29, @07:29PM (2 children)

    by Rosco P. Coltrane (4757) on Monday January 29, @07:29PM (#1342323)

    Added bonus: people can tell from across the wagon that the toilet is occupied. It saves them having to walk all the way to the door and the embarrassment when they try to push the handle and it's locked.

    • (Score: 2) by JoeMerchant on Monday January 29, @08:22PM (1 child)

      by JoeMerchant (3937) on Monday January 29, @08:22PM (#1342327)

      >people can tell from across the wagon that the toilet is occupied.

      On aircraft there are generally lights up high indicating Vacant/Occupied status. Might be a bit fancy for UK trains, I know.

      --
      🌻🌻 [google.com]
      • (Score: 4, Funny) by PiMuNu on Tuesday January 30, @08:37AM

        by PiMuNu (3823) on Tuesday January 30, @08:37AM (#1342370)

        Next you'll be expecting trains that run on time.

  • (Score: 5, Insightful) by istartedi on Monday January 29, @07:30PM (4 children)

    by istartedi (123) on Monday January 29, @07:30PM (#1342324) Journal

    Bathroom doors are one of those things that amaze me insofar as how common it is to fail at such a simple task. The bathroom doors that are good work like this:

    You close the door, then lock it with a mechanism that changes an exterior indicator from "free" to "occupied" with a green/red color to make it universally understood. The opening of the door automatically switches this indicator and of course it's impossible to turn the lock from outside, or to set the lock and close the door. Ideally, a waste bin for towels is by the door so you don't have to handle the knob directly with your clean hands, thus defeating the purpose of having just washed them by exposing them to potential contact with a surface used by somebody who might not have been so diligent.

    The mechanism no doubt costs a bit more than others, but when you consider the expenditures on some of these establishments it's a huge gain for very little money given how often your customers, employees, and YOU will use these facilities.

    The bathroom door is a solved problem, where so many of us collectively refuse to employ the solution. This leads to the awkward knock, the "I think somebody's in thee" conversation, and my standard response through the door of "Occupied!" when I'd rather not be talking.

    Oh, but kudos to the designers of malls where they have enough space to create a serpentine passage and eliminate this problem entirely... except for the stalls. Don't get me started on stalls.

    --
    Appended to the end of comments you post. Max: 120 chars.
    • (Score: 3, Insightful) by Rosco P. Coltrane on Monday January 29, @07:44PM (2 children)

      by Rosco P. Coltrane (4757) on Monday January 29, @07:44PM (#1342325)

      a waste bin for towels is by the door so you don't have to handle the knob directly with your clean hands

      That's not enough. When I go to a public transport toilet, after I wash my hands, I pull a paper towel and use it to touch stuff until I reach my seat and throw it away there. Because people who don't wash hands don't just leave faeces on the toilet door handle. At the very least, I avoid touching seats and furniture within a a dozen feet of the toilet.

      • (Score: 3, Touché) by JoeMerchant on Monday January 29, @09:47PM (1 child)

        by JoeMerchant (3937) on Monday January 29, @09:47PM (#1342334)

        >At the very least, I avoid touching seats and furniture within a a dozen feet of the toilet.

        Said the man who fell and broke his neck in a patch of turbulence, to avoid some potential toilet germs.

        --
        🌻🌻 [google.com]
        • (Score: 0) by Anonymous Coward on Wednesday January 31, @04:35PM

          by Anonymous Coward on Wednesday January 31, @04:35PM (#1342521)
          When the plane is flying in the air, aircraft turbulence can cripple/kill you anytime you're wandering around not belted to your seat.
    • (Score: 2, Interesting) by pTamok on Tuesday January 30, @08:28AM

      by pTamok (3042) on Tuesday January 30, @08:28AM (#1342367)

      The bathroom doors that are good work like this:

      You close the door, then lock it with a mechanism that changes an exterior indicator from "free" to "occupied" with a green/red color to make it universally understood. The opening of the door automatically switches this indicator and of course it's impossible to turn the lock from outside, or to set the lock and close the door. Ideally, a waste bin for towels is by the door so you don't have to handle the knob directly with your clean hands,

      Red/Green is a poor choice, given the prevalence of Red/Green colour-blindness. Most coloured door indicators I have seen are Red/White. I used to know someone who was Blue/Yellow colourblind [wikipedia.org] as well.

      Usually, the exterior of the locking mechanism has a slot for a coin or screwdriver to allow it to be unlocked from the outside, most often used to release small children who have locked themselves in and can't or don't want to unlock the door. Sometimes, instead, the door will have a hole that allows you to insert a tool to raise the latch.

      The trouble with the train toilet is that you want a robust solution that is resistant to vandalism, but simple enough for people who have never seen it before to use. This means that the means of unlocking from the outside needs to be protected (because vandals like glue and general damage), and not usable by those who think it is 'fun' to open toilet doors while someone vulnerable is using it. It also needs to fail 'safe' in case of a power cut, or accident, or malfunction of the mechanism. It is not as simple a problem as the lock on a typical stall in a public toilet.

      I volunteer at a place which has electric sliding doors for the toilets for disabled people, and we have a perennial problem of people pressing the 'lock' button immediately after pressing the door-close button and exiting the toilet while the door is closing. The door locks after it has closed, with no-one in the toilet, making it unavailable for use until an authorised person comes to reset it. The system is terrible, but we can't get it modified or replaced because of a whole load of health, safety, accessibility, and other legal requirements, and the organisation has a chronic lack of cash.

      Unattended public toilets get abused mightily. Which is a shame. Sometimes the toilet is blocked with vast amounts of toilet paper, and someone keeps flushing until the toilet overflows. Sometimes the sink plughole is blocked with paper at the same time as a tap is left running. Sometimes tampons are flushed, which blocks the drain. Some people smear excreta everywhere. There are enough problems to make people decide not to offer public toilets, with the end result that people use alleyways, or bushes and trees, people's gardens, communal staircases and lifts (elevators). The organisation I volunteer for has a non-public toilet near to a local attraction, which we are forced to leave available and eat the huge cost of keeping it sanitary, because we don't want the adjacent green area we are responsible for covered with human faeces and urine. The local council refuse to contribute to the running costs, and don't provide toilet facilities at the attraction.

      The issue I have is not that the train toilet's state machine is unhelpful, or that the controls are badly engineered, but that modifying things to improve them in the light of experience is so unreasonably difficult. The lifetime of a train carriage is measured in decades, and it is likely that people will have to put up with a sub-optimal solution for the whole of that time.

  • (Score: 4, Insightful) by anubi on Monday January 29, @08:38PM (15 children)

    by anubi (2828) on Monday January 29, @08:38PM (#1342328) Journal

    Being an Arduino guy, I sometimes consult with clients on microcontroller application, attempting to minimize complexity.

    This is an ideal example of overdesign.

    Too many single points of failure. I would advise the simple mechanical latch. If a microcontroller was involved at all, it would be a simple webserver serving a page of toilet availability.

    However, I may not be seeing a bigger picture. I read about the guy who got trapped in an aircraft loo for the duration of the flight. Maybe the loo has another use,... A holding cell for unruly passengers?

    --
    "Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
    • (Score: 5, Insightful) by owl on Monday January 29, @09:12PM (5 children)

      by owl (15206) on Monday January 29, @09:12PM (#1342330)

      This is an ideal example of overdesign.

      Indeed, which is exactly what happens when there are too many designers. If the employed designers don't change things, then some bean-counter from payroll will eventually ask the question of "why are we paying all these designer salaries if they aren't doing anything?". So in order to assure their continued employment, the designers must make changes, even if the changes are for the worse, to assure their continued employment. With the result that we get bathroom doors that need CPU powered electric push-buttons for what was once handled by a simple, and reliable, mechanical mechanism.

      • (Score: 2) by driverless on Tuesday January 30, @04:20AM

        by driverless (4770) on Tuesday January 30, @04:20AM (#1342350)

        Indeed, which is exactly what happens when there are too many designers.

        Or when microcontrollers get involved. If this was a simple mechanical device it'd be straightforward, (relatively) reliable, and work as expected. I'm thinking of mall toilets here where you rotate a knob that locks the door and switches a sign outside from "Free" to "Occupied", rather than something relying on a pile of software, sensors, and solenoids to all work perfectly.

      • (Score: 2) by PiMuNu on Tuesday January 30, @08:39AM (2 children)

        by PiMuNu (3823) on Tuesday January 30, @08:39AM (#1342371)

        Bring back XP!

        • (Score: 0) by Anonymous Coward on Tuesday January 30, @12:53PM (1 child)

          by Anonymous Coward on Tuesday January 30, @12:53PM (#1342384)

          Actually, XP looks a lot better to me since someone figured out how to activate XP even though the official activation servers have been retired.

          Look up "XP_activate32".

          I mean if Microsoft isn't interested in supporting it anymore, why do they screw their customer by making it difficult to run what they bought? Just state it's not supported anymore, it's prone for virus, the wise should quarantine it from the internet, your only recourse from a virus infection may be a total disk wipe and reload, etc...

          This kind of obsolence crap reeks of something a substandard shower valve company would do...builders install the valves in a new home, ten years later, the seals in the valve begin to leak, and you can't buy replacements for your discontinued and obsolete valve, and have to spend thousands in plumbing bills to disassemble your shower stall to replace the entire valve assembly. For extra fun, change the type of pipe it fits.

          I say this in appreciation to the Moen company, who still supports their 50+ year old shower valves. Replaced the valve cartridge about a year ago. $25 or so. Home Depot. They even sell the specialized screw-jack cartridge removal tool.

          I feel so fortunate Microsoft doesn't make plumbing.

          Back to eternal activation...

          It's just the ticket for those of us nursing old systems for things like pre-internet databases of old car repair manuals.

          • (Score: 2) by drussell on Tuesday January 30, @02:54PM

            by drussell (2678) on Tuesday January 30, @02:54PM (#1342405) Journal

            I say this in appreciation to the Moen company, who still supports their 50+ year old shower valves. Replaced the valve cartridge about a year ago. $25 or so. Home Depot. They even sell the specialized screw-jack cartridge removal tool.

            My local wholesale plumbing hut happens to be a Moen dealer, and they go one better. When I need a some spare cartridges, I just ask for "another couple posi-temp 1222s" or whatever I need and they give them to me for free. They have boxes of all the common ones right there behind the counter. Obviously, you need to actually buy something from them on a fairly regular basis to enjoy such treatment, but Moen supplies replacement cartridges free of charge to plumbing tradesmen...

      • (Score: 3, Insightful) by anubi on Tuesday January 30, @09:43AM

        by anubi (2828) on Tuesday January 30, @09:43AM (#1342378) Journal

        Busywork of negative value. We have been obsessed with useless anti-KISS technology, seemingly done to appease marketers by giving them more bullet-points for sales presentations.

        I have seen so many expensive-to-repair situations evolve from marketing gimmicks. The device that failed may cost $10, but getting to it to replace it may cost thousands.

        My current woe with my old van involves the heater-A/C blend door. Which involves a lot of dash disassembly to get to. It uses a &*?#$! DC servomotor so it can be controlled by a pretty little slide potentiometer on the dash.

        Why in all blue blazes didn't they use a simple "choke cable"? I could have been able to tell if the door was working by just the feel of the control knob while trying to operate it.

        My old Chevy's heating ducts were all controlled by "choke cables", and the whole time I had that car, those cables never failed, but I did need to lubricate them with sewing-machine oil every few years. They never failed...just got hard to adjust.

        The old school cars taught me a lot. Seeing my neighbors repair bills for maintaining their cars taught me even more. One repair bill they showed me was almost how much I paid for my van! So many problems for a minor "convenience". They can keep their power windows and power locks, but I will keep the power steering and power brakes. Those vacuum actuators that work the heater vents will be replaced with "choke cables" next time I have the dash disassembled. They plumbed those vacuum actuators into the same vacuum system that powers my brakes! Too much risk of a vacuum leak in my book. This is a diesel and I don't have a lot of vacuum to start with, just a small vacuum pump that's monitored with a vacuum sensor switch that lights a brake indicator, which I can verify by tapping the brakes a few times before starting, then start the engine, then see how long the engine runs before the brake warning light goes out. Then I apply brake, take the transmission out of Park, and go. I would sure hate to get it out of Park, THEN discover no brake! People on the truck forum I frequent have posted this woe ( thanks, Cubey! ) and I wanna make sure I don't repeat his experience.

        My goal is to make it KISS. I don't like single points of failure. Computers make a great assistant for routine tasks, but give me genuine human intelligence to take over upon an anomaly.

        I remain very pessimistic about self driving cars, but I may embrace a self parking one.

        I am quite aware of the overcomplexity of software, but I cannot buy a decent washing machine that designers haven't ruined. Refrigerators have the same woe, but I still see the simple ones available. These things are expensive and seem to be designed to fail.

        --
        "Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
    • (Score: 3, Insightful) by JoeMerchant on Monday January 29, @10:02PM (7 children)

      by JoeMerchant (3937) on Monday January 29, @10:02PM (#1342335)

      If they are going to have a microprocessor, they could at least include an IR or other occupancy sensor to have a bit of real-world data for the system to work from.

      With a uP system, as you say the loo can report a simple independent web page, but it can also make its current and historical data available to an aggregator, provide a secure interface to turn the loo door into an intentional prison (with simple porter's key to unlock from the outside in the event of electronics failure) and many other things of probably lower value: big data analysis of utilization patterns - particularly vs station stop times, predictive service intervals for paper towel or soap replenishment as well as regular cleanings, freebie data like temperature over time maybe noise levels and accelerometry, interactive features like a "knock knock" sound after an appropriate occupancy interval when website access indicates others' interest in using the facilities, oh, and these are British trains so of course there will be a queueing feature for interested users.

      For a real cybersecurity nightmare, imagine this on an integrated Japanese toilet.

      --
      🌻🌻 [google.com]
      • (Score: 5, Funny) by driverless on Tuesday January 30, @04:23AM (2 children)

        by driverless (4770) on Tuesday January 30, @04:23AM (#1342351)

        If they are going to have a microprocessor, they could at least include an IR or other occupancy sensor to have a bit of real-world data for the system to work from.

        If you're going to do that then at least do it properly, you want mm-wave radar and a stool sample sensor so you can play ads at the occupants telling them they need more fibre in their diet or to get more exercise, and here's a 10% off code for the health food store or gym membership, please have your credit card ready.

        • (Score: 4, Insightful) by PiMuNu on Tuesday January 30, @08:42AM

          by PiMuNu (3823) on Tuesday January 30, @08:42AM (#1342372)

          Report back to their GP/Palantir as well (USians: that's British English for health insurance provider).

        • (Score: 2) by JoeMerchant on Tuesday January 30, @12:59PM

          by JoeMerchant (3937) on Tuesday January 30, @12:59PM (#1342387)

          Sounds likely.

          The old Blade Runner retinal scan ID for targeted advertising in shopping malls has only not happened yet due to the plummeting popularity of shopping malls.

          --
          🌻🌻 [google.com]
      • (Score: 2) by Zinho on Tuesday January 30, @02:15PM (3 children)

        by Zinho (759) on Tuesday January 30, @02:15PM (#1342394)

        I just heard a report on a Boston electrician saving lives by developing a bathroom sensor to detect opioid overdoses. [wbur.org]

        “Essentially they don't detect motion,” Facher says, “They detect the absence of motion. So, if someone's in the restroom and the door has been locked behind them for two minutes and 45 seconds, and no motion has been detected, that's when these alarms go off. And that's when medical staff can come in, force the door open if necessary, and do the things that need to be done to revive someone from an overdose, which include administering Naloxone, the overdose reversal medication, sometimes rescue breathing techniques using supplementary oxygen.”

        If we're going to add electronics to public bathrooms, let's at least make them pro-social.

        For anyone who's iffy on spending money to rescue drug abusers, remember that it saves the bathroom staff the trauma of needing to evict a corpse from the facility instead of calling an ambulance. That should be a win in anyone's book.

        --
        "Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
        • (Score: 3, Interesting) by JoeMerchant on Tuesday January 30, @04:42PM (2 children)

          by JoeMerchant (3937) on Tuesday January 30, @04:42PM (#1342414)

          >anyone who's iffy on spending money to rescue drug abusers

          Most of the opioid abusers I know are white, male, over 50, and staunchly conservative. Rush Limbaugh was far out-front, but since he was "outed" I have come across a half dozen of his fans who also had "pill problems" - to the point of being "Baker Acted" which is Florida law for: danger to self or others, checked into a treatment facility - which amounts to a jail that looks like a hospital, but very much acts like a jail.

          --
          🌻🌻 [google.com]
    • (Score: 4, Touché) by DannyB on Tuesday January 30, @03:00PM

      by DannyB (5839) Subscriber Badge on Tuesday January 30, @03:00PM (#1342407) Journal

      Do not use an Arduino. Use a Raspberry Pi. Don't under engineer this. In the specs require Kernel 7.x, which should be available by the time this new lock has been designed, built, tested, scrapped, project re-launched, re-designed, re-tested, etc, etc until it is eventually accepted once legislators are "convinced" to mandate this new lock on all trains.

      The microcontroller should not only serve a web page with the status of the toilet occupancy, it should also allow you to reserve your place in line. However an app should be heavily pushed on the user to be installed rather than using the web page.

      To reduce costs a 50 cent fee should be charged for use of the toilet. Insert 25 cents to get in to the toilet. And to get back out you must insert the remaining 25 cents. Management recognized that splitting the fee this way ensures that people don't accidentally open the door to exit before they truly intend to exit.

      The app could allow you to pay in advance when you reserve your place in line. You would also use your phone to open, close and lock the door. That way you only have to touch your phone screen.

      To allow emergency entry to the toilet, the app could offer a number puzzle to be solved in order to open the locked door from the outside.

      This seems to solve all of the problems with a truly 21st century cloud based solution worthy of executive bonuses.

      --
      When trying to solve a problem don't ask who suffers from the problem, ask who profits from the problem.
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