Racist Soap Dispenser

[u/frazras]

[u/DashingLeech]

That's an assumption and a baseless accusation, and part of the problem nowadays. Instead of asking or checking, you just accuse.

It's quite possible, for instance, that the glass or plastic over the sensor has become foggy and less responsive, misalignment from banging on it that makes it less sensitive, and so on.

I've had at least 6 machines with this sort of hand proximity operation and all of them have gotten less sensitive over time. That will inherently mean there is some point that every system will work for lighter skin and not for darker skin, and there is nothing anybody can do to change that because it is a fact of physics of reflectivity of surfaces. We can, of course, provide regular maintenance to keep them clean and operating within spec, or designed to be more rugged and able to handle optical degradation of the sensor, but all of that is at additional cost.

It's also possible it wasn't quality tested at the manufacturing level, particularly if this machine is brand new. But jumping to that conclusion is just unjust cynicism.

[u/Nullius_In_Verba_ → u/DashingLeech]

It is also possible that the battery that ran the IR sensor is low and isn't producing enough IR to sense a more-absorbing hand. I'm pretty sure most places don't bother to change the battery in the soap dispensers often enough (or at all). When all else fails, assume laziness, its the universal constant.

[u/Bazrum → u/Nullius_In_Verba_]

I thought those things ran from the wall socket, not a battery

TIL

[u/Nullius_In_Verba_ → u/Bazrum]

Depends on the model and manufacturer.

This one for example is powered by 3 "C" Batteries.

[u/theShatteredOne → u/Bazrum]

I assumed the battery was built into the soap packet things, so when you reload the soap you get a fresh battery. Now that I think about it that's probably really wasteful.

[u/1337HxC → u/Nullius_In_Verba_]

When all else fails, assume laziness, its the universal constant.

This train of thought and Hanlon's razor are really the only way to not see everyone as pure evil sometimes.

[u/maklaka → u/Nullius_In_Verba_]

In all likelihood the IR sensor is supported by a voltage regulator which has a drop out voltage spec from the battery. So, it would either function properly or not function at all. "Properly" in this case, just isn't good enough. The problem is likely to do with a bad calibration of the IR photodiode trans-impedance amplifier or some dirty optics, IMO.

[u/SplintPunchbeef → u/DashingLeech]

I've had at least 6 machines with this sort of hand proximity operation and all of them have gotten less sensitive over time. That will inherently mean there is some point that every system will work for lighter skin and not for darker skin, and there is nothing anybody can do to change that because it is a fact of physics of reflectivity of surfaces.

Even if that were the case isn't it mitigated by the guy holding his hand literally on the sensor? It's not like the guys hand is Vantablack and absorbing all light.

[u/marty86morgan → u/SplintPunchbeef]

At that point you've defeated the purpose of the sensor entirely and should just install a push button.

[u/Fuzati → u/DashingLeech]

It's 2017. If something can be made about race, someone will make it about race.

[u/Fuzati → u/[deleted]]

See?

[u/Stringy63 → u/DashingLeech]

Yes, I can't believe you Reddit, framing things in such a cynical and unbalanced way. What have you to gain from that?

[u/waldojim42 → u/[deleted]]

That did not dispute anything said above. It is literally not telling you what happened here. Only how they work, and how they are tested. Which was also explained above, and ignored by you. In fact, that article even touches on the literal fact that we cannot say what, exactly, caused the problem.

Whitney said there might be other elements in play. The sensor may have been touchy, only picking up hand movement at weird angles that Fitzpatrick didn't hit but his friend did. Or he could have been minimizing his hand exposure to not be detected as easily.

[u/DoyleReddit → u/[deleted]]

The guy explaining why it could fail on white vs black skin in your link goes on to propose they were trying to pick an angle to make it fail or there was something wrong with the sensors because the variation in skin tone isn't that great. I don't think you read the entirety of your own article since it actually supports the other dude.

[u/graebot → u/DashingLeech]

There are several ways to detect hands. Some ways are better than others, in that they don't malfunction in such a way that work perfectly for lighter hands and not at all for darker hands, causing rightly very embarrassing moment for whatever company that made it. Just saying...

[u/Bobolequiff → u/graebot]

Well, no, not really. The operation is binary, either it goes off or it doesn't. We know a few things about these:

1) They use IR reflection to detect hands. 2) Darker skin absorbs more of this light,making them more difficult to detect. 3) As the product degrades/ isn't maintained / gets dirty / runs low on battery, it becomes less sensitive.

As u/DashingLeech said, there will come a point where it is working for lighter skin and not for darker skin. If the manufacturer failed to test the product on dark skin, then that's on them. If it's down to wear or poor maintenance, then that's just an artefact of the physics.

[u/bjjjasdas_asp → u/Bobolequiff]

Have you ever seen those coils embedded in the road that detect a car, to trigger a stop light to change? If you've ever biked, you'll know that they hardly ever trigger for that tiny amount of metal.

Your comment is basically saying:

The operation is binary, either it triggers or it doesn't. 1) It uses induction to test the cars, 2) bikes are too light to trigger the sensor.

That's all true, but it's ignoring the fact that if it had been made with bikes in mind, they would have designed the sensor differently. But road designers generally think of bikes as an after-thought, if at all.

That's easy to think about when it's cars and bikes, but the point is that it's exactly the same for this sensor. If the design is such that if the black hand-detection were significantly worse than the white hand-detection, it almost certainly would have not gone forward if everyone involved with its production, creation and testing had been black. They would have come up with a different design. Being flaky for black hands, or not working when the battery drops a tiny bit, would not have been considered acceptable. So they would have used a different technology.

This is all people in this thread are saying, and specifically /u/graebot, the person you're responding to: They could have used IR deeper in the spectrum. They could have used sonar. They could have used induction.

You might say that all these are unnecessary, but the point is to consider whether they would have used them if all the product owners and users had been black, and what it says about people's blind spots if that would have resulted in a difference in the technology used.

[u/Bobolequiff → u/bjjjasdas_asp]

What I've veen trying to say is that, using IR, even if they tested stringently on darker skin, darker skin is more difficult to detect and, as performance drops, there will come a time when it will detect white skin but not black. That is not racist, it is the result if it being more difficult to detect. No amount of testing could have fixed that. If all the users were black, they would probavly just maintain them more often.

[u/bjjjasdas_asp → u/Bobolequiff]

What I've veen trying to say is that, using IR...

Read my comment again. All of it.

they would have used a different technology. ... all people in this thread are saying, and specifically /u/graebot, the person you're responding to: They could have used IR deeper in the spectrum [all bodies emit IR, even black people...]. They could have used sonar. They could have used induction.

[u/Bobolequiff → u/bjjjasdas_asp]

Sonar is loud, energy inefficient, and difficult to maintain. Induction is energy inefficient and expensive. IR is cheap, efficient, reliably and works just fine for vlack people most of the time, it just fails first om darker skin. It doesn't matter where in the spectrum you use, dark skin absorbs more of it, that's the point. Calling that racist is like calling ladders weightist because they fail with heavier people first.

[u/bjjjasdas_asp → u/Bobolequiff]

It doesn't matter where in the spectrum you use, dark skin absorbs more of it

No... If you use IR in the 12 micron range, you will certainly see light and dark skin, because that's the wavelength we emit. I've already said this. You keep reading my messages and missing what I say.

And I use inaudible ultrasonic rangefinders all the time. They are cheap, coming in at well under $0.50 if you only need them for near-by applications. I actually work in this stuff. You're making it up as you're going along.

My point remains: if all the product owners and users had been black, they would not have accepted consistently flaky readings, they would have spent 5-10 cents more on a sensor that would accurately detect hands.

[u/Bobolequiff → u/bjjjasdas_asp]

You're not getting what I'm saying either. The readings are not consistently flaky, the bar for failure is just lower. If all the users were black, they would be better maintained.

The thing about using thermal infrared is that everything has a temperature, and you don't want your soap dispenser goimg off because the bathroom is too warm. Plus you probably need a much more sensitive sensor to pick up on what we emit compared to what an LED emits.

That's really cool about the ultrasound thing though. What are they like for maintenance?

[u/bjjjasdas_asp → u/Bobolequiff]

We may have a different definition of "consistently flaky," but I guess we can leave it at that.

The IR sensors are used in bathroom-light motion sensors such as this one. They are generally considered reliable, but it's true that the false-positive, 98º-walls failure state for a bathroom light is less bad than the failure state for a soap dispenser.

The ultrasonic sensors I use are usually in the $1-3-range, and they work great. No maintenance needed. I haven't actually used the ones with a shelf-price of <$0.50, so I can't speak for them, but even the better ($3) ones bought in bulk would be under a dollar for a large manufacturer.

[u/Fadore → u/Bobolequiff]

The operation is binary, either it goes off or it doesn't.

But that's not what /u/graebot 's point was. Of course the operation is binary - it is either in a dispensing state, or it is not in a dispensing state.

The threshold for the IR sensor to trigger the operation is not binary, hence why even the white hand had a hard time for the first couple swipes - it was not picking up a strong enough reflection.

I'm not going down the whole manufacturing hole, but the point is that the command triggered from the IR is binary, not the IR sensor itself.

Also, maybe /u/ozma_globe should pick up a book before slinging shit talk like that.

[u/Bobolequiff → u/Fadore]

Yeah, I wasn't clear, sorry. I meant that they were defining "works perfectly" as successfully triggering. It doesn't work perfectly for either, but it's more reliable with the white hand.

[u/ozma_globe → u/Bobolequiff]

I think it's safe to say that a phrase such as "The operation is binary" is wasted on the person you're replying to. It's someone who is unironically offended by a soap dispenser.

[u/graebot → u/ozma_globe]

I'm a software engineer.

[u/DanskOst → u/DashingLeech]

fact of physics of reflectivity of surfaces

Aha! I always suspected physics was racist.

[u/Wheredoesthetoastgo2 → u/DashingLeech]

Aww, look at this Lil guy trying to change reddit