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Lets talk about washing machines...

8/12/2019

1 Comment

 
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What does AEG stand for? "Aggravation, Exasperation, Grief" perhaps?
So, some three years ago I made the fatal error of buying something without having done my homework first. In this case, a very, very expensive washing machine made by AEG called the "Lavamat Turbo." For Google robots and anyone else who may be suffering the same fate and would like to read my tale of woe, the model number of this particular pile of junk is l61470wdbi.

What's wrong with it, then?

Well, it's a two pronged attack from this beast - not only is it terribly made from a reliability and construction quality point of view, but it's also incredibly poorly designed.

Last night, it died for the third time. I'm not sure that one breakdown per year qualifies as decent quality in anyones book, but consdering how ancient I am and the fact I've never actually managed to break any other washing machine in my life, this must be some kind of indicator as to just how appalling this particular machine is. Oh, and I'm fully aware how old I sound recounting my illustrious, long history of washing machine ownership, but there's definitely a technology angle here so bear with me.

The fault, then, was an interesting one. Turn the machine on, select a program, press go. The door clicks, all the lights look happy. As you would expect, I then walked away thinking nothing more about it - the days are long since gone that watching the washing machine cycle to completion was a form of family entertainment...

Then it struck me how quiet everything was. Too quiet. I went back to find the timer happily counting down to itself but literally nothing happening at all. No movement, no water, no swishing of laundry. Eerie silence.

What's wrong here is this - the machine was doing two things:
  • Not working (obviously)
  • Carrying on as if nothing had happened.

"Ah! But if it's faulty what can you expect?!"

Being unable to believe anything is fixable only by a professional, I started poking around the internet for answers. It turns out that this machine has error codes. How useful! Yes, if only they actually appeared on the display. This is where, from a design and software engineering point of view, things get really stupid. I learned the magic incantation and performed finger acrobatics on the buttons to reveal the magic error - E41.

What's wrong here?
  1. The machine knows it has an error
  2. The machine has decided that even though it has an error it will.... carry on as if nothing is wrong?!
  3. The machine hides the error code from you! It's a secret!
What makes it worse is that in certain circumstances it will actually show you an error code if something goes wrong, but not in most cases.
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If you see this washing machine, run. Run like the wind!
This is just plain stupid. It cannot even be argued that hiding the error code in some way helps prevent confusion or even protects customers from coming to some kind of harm - it's information! Nothing more. Why decide that some errors can be displayed and others are only for those who have sworn an oath and gone through the sacred order of the washing machine repair person, complete with complimentray rubber seal crown?

Some of the errors it will show you are comedy - there's one called EFO which tells you the water is leaking everywhere. This is one of the errors they could've hidden. I know this becase when this very machine flooded my kitchen it was very, very obvious what had happened...

It is these inexplicable design choices that make my brain boil. I keep going back to this point - Steve Jobs was a genius because he recognised the need for complete and utter design consistency. The need for items to behave in such a way that you never needed to ever encounter a machine behaving in a seemingly random or inexplicable way. Like it or not, this washing machine would never have made it to production if he'd been inclined to design kitchen appliances.

When designing a system, choices are made. Somewhere, at some point, someone consciously made the decision that this machine would have a comprehensive set of diagnostic error codes to help the repair process. However, they also made the decision that this valuable information should be hidden and that the machine should just pretend nothing is wrong?

So what's actually wrong? Well, E41 means that probably the door latch is in some way broken. Either that or the main control board has fried itself. This is one of those "worth a punt" situations because the door lock is £13 and for once I don't have to hump a machine that weighs more than an elephant out of a cupboard to try and fix it for once. The part has been ordered and we'll see what mess I get into when I fail to reseat the seal round the door properly.

The machine that keeps on giving once decided to flood the kitchen. This is something that shouldn't really happen on a grand scale. Would you like to learn about washing machine electronics and control? Of course you would.

I was surprised to learn that the way in which a machine judges the amount of water that is inside it and when to turn the tap off, is not by measuring the flow of water in to the machine - which just seemed to be the way to do it in my head. Instead, there is a small rubber hose inside that has a pressure sensor on one end. As the machine fills with water, the air pressure increases until the sensor reads a certain amount and the control board shuts off the supply.

This is actually quite a reliable way of doing things until. that is, the rubber hose gets a hole in it. This "shouldn't" happen, but it was pub time in the AEG factory when my machine was built and they couldn't be bothered to attach it properly so the drum rubbed a hole in it.

No problem - the machine has a feature to prevent this very problem! It's even part of their sales pitch, the machine is intelligent enough to cut itself out should it suffer any failure in the water department. The question is... why did my kitchen flood then? The answer is wonderful.

Inside the bottom of the machine lies the answer to this "intelligent" function. It's a piece of polystyrene. When water escapes the machine the bottom of the machine floods, the polystyrene floats up which clicks a switch that tells the board to cut the water and turn the drain pump on.

Brilliant. Such a simple solution! With only one minor problem.
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"An excellent plan, sir! With only two minor flaws. One, we don't have any rocket pants and two, there is no such thing as rocket pants except for in the fictional cartoon strip 'Robbie Rocket Pants'"
The problem is that the bottom of the machine isn't water tight, meaning a lot of water has to accumulate around it before the little float can do its job. Furthermore, the float has to raise about 1cm before it triggers the switch. Trust me, 1cm deep is a lot of water outside of the bath...

In a world where devices are becoming more and more "smart" and more connected for no reason other than "we can" (why I need a wifi washing machine I do not know) there is a desperate need for us to understand that simplicity is still the number one most important factor when designing anything electronic. The fact is we shouldn't forget that the very word "appliance" means something that should be plugged in, maybe have one button pressed and it just goes and does the job it was designed to do. A lot of the time we are trying to solve problems that sumply don't exist or create "convenience" that is verging on the absurd (smart lights anyone?) for the sake of selling kit, rather than actually adding value.

The day my house gets smart lights and an internet connected fridge and washing machine is the day I buy a large set of wire cutters and go on a snipping spree to rid myself of the madness.
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      • Unit 1 - Computer Systems
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