Found it. The wayback machine has an instance of the site, which has a pastebin link for the sketch. The link’s still good! I found the drawing on a parts website for the Maytag QuietSeries 300.
Sketch:
http://pastebin.com/raw/0Zec1xLc
Drawing:
See attachment.
I have a Maytag QS300 dishwasher with a burned out control panel, an Arduino Uno, and a subscription to the Hackaday RSS feed. They featured this a while back.
This be my first microcomputer project. Got the wiring from the dishwasher broken out and labeled, and everything hooked up to an optocoupled relay board. Sanity checked everything.
This is a good model to do this with, judging by the wiring diagram, since it seems very sensibly designed, ostensibly with safety in mind. I've watched enough AvE and read enough Hackaday to know this is a good thing.
The door latch has a dual pole switch for the line and neutral mains wires which is normally open when the door is not latched, the heater is in series with a thermostat to protect from overheat, and the water fill valve is in series with a float switch to prevent overflow.
These protect against faults directly and don’t rely on the controller to sense a fault condition and appropriately respond to it. Instead they interrupt the circuit in the case of a fault condition. If they’re REALLY done right they should also fail in a safe manner as well, but I haven’t checked to see if this is the case.
Also, if the the drawing is correct this model has a soil level sensor, which I’m guessing is implemented as an LED shining through the drain water onto a photoTRANSistor. I think I’m reading that symbol right.
I threw in some pictures of the factory PCB and wiring harness.
Currently (pun intended) the relay board is dangling down the front of the unit, which wouldn't be normally be an issue, except that my unit has a stainless steel façade, which I'm worried could short the traces on the board, so I tossed the whole lot into a Ziploc bag.
Will update this when I've tried running the sketch.
