Riding the Flow

musings from the shire

Washing Machine Modding

So I have this washer-dryer which I really like, used it for years and for this reason even bought exact same model when moved to a new house.
It very good no-frills design, and, most importantly, actually performs all functions well - for example, dryer function actually produces *almost dry* laundry unlike my first Bosch which only produced damp&hot.
But it has one downside - it does not have an audible signal. With the main annoyance that you often miss the end of a cycle, which most commonly happens - you load the machine, it runs for some hours, then you busy with other things, and then its finished, but you've forgotten to check it. Its not the end of the world, but laundry sitting inside drum for long time quickly becomes wrinkled (and in dryer case it gives opportunity for moisture to re-settle).
Also even if you listening for machine to become quiet, this does not actually mean its ready to open the door - because there is time-delay lock on the door which clicks open only some minutes after.
Previously I've already done some repairs to it (when badly clipped cable got in contact with cooling fan which produced screeching sounds when dryer was on and chopped cable insulation). So I was familiar with layout more or less, and even managed to find the service manual with schematics.
So I've decided to mod the end cycle buzzer indication using some dirt cheap Arduino parts. The idea is very simple - Arduino sits here and monitors state of door lock, when it opens, it beeps for my attention.

Unsurprisingly, a lot of sellers from Asia are now looking at Amazon as good trading front for their business. While not being stereotypical and there are always exceptions, there are a awful lot of "cost effective goods" sellers here (read: awful goods when you truly get what you pay for).
I have found (by my own prolonged experience) that great amount of these sellers on Amazon nowadays employ following tactics (almost identical, save by bits of difference here and there):