And every dishwasher needs an option to not reset the clean setting it the door was just opened and closed within a few seconds. I loved his idea to only reset it if it's open for a few minutes, indicating enough time to have emptied the dishwasher.
I wonder if he think his little project was worth not buying the $150 replacement part? Clearly it was a lot of fun.
I own Fisher & Paykel dish drawers. They are mostly wonderfully engineered. A clever bit about them: they open the fill falve and shortly after start the wash motor. Then they measure the draw of the motor circuit. When the draw is sufficient (due to the motor working harder against the water), they know enough water has entered and close the fill falve. At one point, one of my fill valves failed and the water wasn't entering quickly enough. This eventually triggers a timer, and the drawers shuts down telling you the water isn't entering quickly enough. Mechanically, you can also work on them almost without tools. Anyway, just thought I'd post a bit because I really appreciate good design.
(They also have an interesting bit of poor design that has caused them to leak out water onto my floor after a plastic part broke. Sigh.)
The main thing preventing appliances from becoming future proofed is crappy parts(mostly the mechanical parts). For example, in the past a washing machine had lasted 20 years. today it's 3-4 years.
There are high end brands who have a guarantee of more than 10 years, but they're expensive and the cost per year comes about the same as the cheap ones.
And after those 3-4 years, you can probably get one that washes better, quieter, and uses less water and energy (all of the above perhaps only marginally), for the same yearly price. It's not really that bad of a trade-off.
sI'm not so sure. I think it's perfectly reasonable to replace an appliance after 10 years. I've lived in some apartments that had appliances from the 80s; mechanically, they were still sound but the colors were off, rust was forming and each felt like it took longer and was a little bit less effective.
One particular case was the refrigerator. No matter how much we cleaned it it smelled like mildew. As it turned out not only were the door seals bad, the internal liner was breaking down and the foam insulation had degraded. Replacing it with an A+++ rated model was the best thing to happen to us. Not only was it quieter, it only runs 1-2x per day, has more internal storage, and it cut the electric bill by 20%. This thing will pay for itself in 2 years with the electric bill savings only.
There are many things to be said about making old devices work again but sometimes you have to ask if it's really worth it. I'm pretty certain that old refrigerator pump would have ran for another 20 years.
Thinking about this in terms of what low-level actions are being performed by the Arduino (relay closures, sensor readings, basic I/O), it strikes me how this can be an alternative/complement to platforms like LabView. I feel this is significant due to the prevalence of these platforms in engineering education as well as in industry R&D, test labs, etc. - in my opinion, the more (different) tools that are available and to which people are exposed, the more likely these people will be engaged (in the case of engineering education) or able to get their jobs done.
Yes, of course it's a good complement for industrial or laboratory automation, test automation, industrial control. There are loads of different ways to solve these kinds of things, and they are all used somewhere...
But in bigger companies, there's the issue of standardisation: A company policy might mandate that all test-automation has to be done with LabView, so even a simple "dishwasher complexity" device might be implemented on a dedicated PC because it's just cheaper to shell out the $1000 for hardware than to re-train engineers to do Arduino on a $20 board.
Or some other company (possibly more industrial automation inclinded) might do everything with Siemens-S7 controllers.
This is why in reality you often see things setup with the apparently wrong tool for the job, but limiting the number of choices might make (business) sense.
Reminds me of the project that a guy added twitter support to his washing machine. I for one would like to know when my washing is done without having to walk all the way down the stairs =)
If you want to shorten the innovation cycle in any product to be more like that of software, the easiest, most trivial way to do so is to make it software upgradeable.
This device might deal quite badly with inductive loads such as the dishwasher motor or heating element (often wound in a spiral).
The lifetime of the solid-state-relay will be reduced if you don't use the proper subber circuits (see for example the S202S02F datasheet found as the first google hit).
A old-school mechanical relay might be a better fit.
To drive mechanical relays, the ULN2003 is a very handy part. It's 7 transistors + freewheeling diodes + resistors in one 16pin DIP.
