The microcontroller obsession is real. As is the desire to do everything via software and not mechanically - see touchscreens in cars. I'm pretty sure it's because as developers, we're addicted to the notion of making everything software-defined so you can change everything later if needed. As a developer it's a thought process I understand well, but seems to increasingly lead to detrimental outcomes, like the extreme touchscreenisation of cars - awful from a safety perspective.

I am told that "superloos" (those automated self-cleaning toilets installed on the pavement) do have some kind of time limit and will play some kind of audial warning a few minutes before opening.

More concerning about those toilets are stories where people somehow managed to be inside the toilet when the self-cleaning process started (which involved the entire chamber being filled with liquid). Supposedly this would happen when someone used the toilet, but held the door open as they left so someone else could use it without paying. The toilet, then thinking it was empty, proceeds to unwittingly try and drown the "undeclared" occupant.

I can’t imagine there not being some kind of “hey I’m still in here” button or slider or whatever. Preferably not electronic.

You're saying the entire indoor volume of the "superloo" gets flooded with water, like a sinking submarine? Don't be absurd. That'd be a monumental waste of water and it wouldn't even clean that well.

It sounds odd to me. I'm merely recollecting a news report from probably about 20 years ago, which is probably going to be hard to dig up. If it's another case of the press getting something totally wrong, that wouldn't be surprising.

I would imagine getting suddenly sprayed with cleaning solution from multiple directions is probably sufficiently unpleasant that it will get exaggerated as it's re-told.

And "the entire chamber being -sprayed- with liquid" plus "I felt like I was drowning" could easily get misquoted as well (or misremembered, 20 years ago is certainly more than long enough for me to screw up details).

So my guess is that what actually happened is something of that ilk.

In some you'd get doused. In others you'd get crushed[0]

0: https://www.bbc.com/news/uk-england-london-64430454

Are there really toilets that are filled with liquid?

No, that would be extremely wasteful, impractical, and ineffective.

It’s not because developers want to work with toilets or other mundane things. Is because the system we all live in has become obsessed with taking everything we do.

>>we're addicted to the notion of making everything software-defined so you can change everything later if needed.

Man, hammer, nail, etc

whale?

> which involved the entire chamber being filled with liquid

It doesn’t. That would use way too much water and not even be a good way to clean surfaces.

There’s jets of pressurized water spraying and sometimes (I believe) air to dry everything afterwards, so the worst that would happen is that the person inside would get an unexpected shower:

https://youtube.com/shorts/4o6pzvn_tkc?si=xvw1X0HwwTY8jifw

oh gawd, is this the trend of videos now? i knew we had gotten bad, but this is just wow. is this one of those situations where if you give speed to an adhd person, things become calmer for them? so if you have adhd, this seems normal?

digitally-mediated autism is a form of environmental autism !

Somewhat related, I just discovered that the Boeing 737MAX replaces the CDU keyboard in the cockpit with a touchscreen emulating the same keyboard.

https://www.gableseng.com/wp-content/uploads/2020/05/G7330-....

I am lost for words...

This actually makes sense from maintenance/reliability perspective.

This doesn't pass the smell test at all. There are multiple redundant CDUs and I'm not aware of any reliability issues with their keyboards in the countless other aircraft models which use them. And I second everything @etskinner just said above.

It's 100% about programmers wanting to make everything software defined.

I really doubt this was made because a programmer asked for it. It's likely way cheaper to manufacturer than the part it replaces.

And it makes no sense from a usability/safety perspective.

Touchscreens are harder to hit buttons right when you're being jostled about by turbulence. Not to mention how easy it is to hit the wrong button even when there's no turbulence. Have you noticed how liberal all smartphones are with autocorrect lately?

Also the fact that with a set of switches, if one doesn't work, it doesn't affect the others. Touchscreens seem to fail all-or-nothing, or at least have large areas suddenly become unusable.

The flight deck of the Airbus A380 widebody airliner must be the most comfortable and ergonomic in existence, with a full laptop-style QWERTY keyboard for each pilot and two additional mini QWERTY keyboards on the center pedestal. There have also been no fatal accidents on the type; maybe the well-designed cockpit has something to do with that.

https://upload.wikimedia.org/wikipedia/commons/a/a4/Airbus_A...

Not really. It's a cost-cutting measure. Keeping the old UI lets them pretend it's the same plane as the original model from the 60s and pilots don't need training.

My keyboards last longer than my touch screens, with the exception of that crappy patch Apple masterminded a few years ago.

Are they needed in emergency situations?

Another difference is a train toilet has to allow unassisted use by a wheelchair user.

Yes this is true. But I don’t think you need electronics for that. Or maybe for opening and closing the door, but not for locking?

I suspect it just boils down to minimising the number tasks staff are responsible for, so you can reduce the number of staff needed. Aircraft need to have attendants for safety reasons, and the minimum number of attendants is dictated by the number of passengers. Most of the time airplanes aren’t in emergency situations, so you’re got lots of spare staff aboard, and you can use them to look after toilets and feed passengers.

Trains on the other don’t have such minimum staffing requirements and usually operate with only one or two staff total (driver plus maybe a ticket inspector). Train operators want to keep staff on train to an absolute minimum (people cost money after all), but those staff still have some safety responsibilities which can’t be removed. Instead you try to remove every other responsibility they might have, such as dealing with toilets.

Automated toilets means the toilets themselves can be responsible for the vast majority of their operations, and can be trusted to fail safe if something unexpected happens. Meaning there’s no need for staff to perform regular inspections while the train is in service, and no need to worry about something going silently wrong and hurting someone. Instead the toilets can ensure that unsafe situations don’t happen, and proactively alert staff if something unsafe does happen.

An old fashioned handle and lock is about as low maintenance as you can get - far less than a complex locking mechanism requiring a computer reboot from the cab to handle when a passenger gets stuck in because they can’t figure out the “open” butto

It’s there for disabled accessibility. The manual lock can be difficult from a wheelchair.

I had a similar thought untill I read that actually for or people with motor/muscle issues issues, a push button or something like the lever in the above which doesnt require physical strength is much easier.

I think the original introduction of the button was due to accessiblity. my understanding is that on newer planes they are trying to move towards a similar system for the same reasons.

A lot of it is reduced BOM. You can get a more robust solenoid lock and control it with a microprocessor for less than the cost of a robust, fully mechanical system, which is a system that needs mechanical maintenance and is subject to all sorts of false inputs like people putting all their weight on a lever.

Buttons flush with the surface or low profile levers such as the ones shown in the picture can me be more robust against certain mechanical attacks simply by having lower weight, lower travel, and being smaller (don’t need to exhibit mechanical advantage).

I’m a fan of simple mechanisms with no software in them whenever possible, but I don’t have to deal with the cost and reliability problems.

Won't a solenoid lock with microcontroller circuitry have a higher risk of failure due to water damage, power surges, and other factors(software bugs, hackers, cosmic rays!), in addition to wear and tear of a mechanical lock?

Probably not for some of the reasons described. The maintenance issues are part of the customer TCO.

Nobody (neither mfr nor customer) takes this path for the sex appeal. This is a B2B product (train car) so BOM and TCO drive everything.

The problem here is that the customer is not the passenger.

Well, it’s not such a big problem as it is in, say, health care.

It’s in the train co’s interest to have working toilets (not too many, because they displace seats but some) and have them reliable and easy to maintain (else costs go up, maybe even they need more per train). This is why they care about a denial of service attack (btw an electronic one can tell the conductor when the toilet is locked for a grossly atypical duration).

So to that degree the interest of the carrier and the passenger are aligned. This applies to most of the carriage decisions (robust seating, working doors and brakes, and so on).

> It’s in the train co’s interest ...

But the if the trains pass first inspection, then it no longer is a development issue but a maintenance issue. [1]

It's not as if train companies can afford to run a statistically significant number of carriages from different suppliers to see which one gives them the actual best bang for buck 5 years down the road.

[1] Rule-proving exception: the Fyra trains. https://en.m.wikipedia.org/wiki/Fyra

The short version: high speed trains failed and were eventually returned (2014) to the manufacturer for ~2/3rds of new price. (That's the exception part.) There have not been high speed trains on this traject since. (That's the rule-conforming part.)

Seems a bit overengineered. Especially when you are in a rush, the last thing you want is fiddling with locking mechanisms. You want to control the door yourself. Swing it open, then slam it, and shut it asap.

Train toilets have become complex systems since the days of there just being basically a hole the floor. This is due to many factors such as not having to prevent people from using them when at a station or people getting hit by sewage in the country side when a train passes. Additionally the toilets need to be accessible and environmental friendly nowadays.

Sadly all of this adds complexity and more possibilities for failure.

In Switzerland we have bioreactors [1] in newer trains which are like a mini sewage treatment plants. These are still very new and still have bugs that are being worked out such as how much oxygen needs to be provided etc. Until recently it caused a bad smell at the main station which is ironic since that is what we used to have in the 80s with the old dumb toilets.

[1] https://news.sbb.ch/artikel/114447/unangenehmer-geruch-aus-b... (German)

Yes, but nothing in your answer actually justifies why the locking mechanism needs to be so complicated. As the previous poster rightly pointed out, airplanes are also not slinging shit overboard at Mach 0.8, and they manage with a perfectly simple sliding mechanism. Or, staying with modern trains, the French TGVs also don't have such an over-engineered solution.. Although, agreed, they don't have on board nuclear reactors to prenuke their toilet waste.. That might warrant a 3 button system with voice control..

There’s no reason you can’t flush in a station - modern trains don’t just drop onto the track (and people have to work on the track, so the station is just a PR thing to avoid offending passengers)

In the U.K. any train from the last 30 years fills a tank, like an RV, including ones with physical locks.

These train door locks also report to a light at the front of the train that the toilet is occupied. That way you know where on the train the nearest unoccupied toilet is, and can decide to stay in your seat a bit longer or venture to a further away part of the train if your need is desperate.

They also auto-close the toilet door when not in use to keep smells away.

And the main reason: Doors aren't really wheelchair friendly - many wheelchair users aren't strong or agile enough to move a door.

With those 3 things to deal with, it's pretty hard to design a mechanical door system that can meet everyone's requirements.

Having said that, the UI could certainly be better. I would personally have had the 'close' button require to be held down the whole time the door is closing. If you release the button early, the door opens again. Only when it is fully closed will it then stay closed and 'locked'. No need for an actual mechanical lock, but there should be a big red padlock light that comes on.

While that certainly explains why they might use a microcontroller, it's certainly not necessary. The lock can be connected to a simple switch used for signalling occupancy, same as any security or commercial fire protection system. Auto-closing and auto-opening are akin to an automatic door, which operates just fine as a regular door, but has a fairly dumb motor attached for accessibility. Perhaps the microcontroller solution ended up being cheaper - but based on this (particularly going to out of order after such a trivial "hack"), the mechanical solution is far more robust, because at worst you can still operate the door manually.

It's a treasure trove of data to know the bathroom utilization rate normalized for passenger volume and time spent per session. Maybe train bathrooms are highly unoptimized. Do trains which frequent downtown areas with bars and sports stadiums need more bathrooms? Maybe there is some kind of flex use option for low passenger count trains to make use of that space but also provide a buffer for commute hours? Does the speed/acceleration/jerk of the train impact bathroom habits? Could this be used as an early warning system for possible food poisoning outbreaks? How can all of this be factored into ads we can serve the bathroom user?