The Aussie site seems to be lacking somewhat in explaining the rudimentaries of how things are working. You can't blame them really as there is such a big variation in what peeps may need to know.
What has to be pointed out here is that once a circuit has been developed and a programme written, it is elementary teenage school stuff to make a circuit board and stick in the components. The programme will have been written and checked, so all you have to do then is download it to the $2 picaxe chip and away you go you have an all singing and dancing microcontroller dedicated to whatever brewing task you have told it to do. The guy who makes the stirplates and all that nice stainless thermowell stuff could knock up kits of everything needed with no sweat...
I have downloaded the picaxe manuals and had them printed out and cheaply bound so they are easy to read. While a whole bunch of it is gobbledygook as far as my brain is concerned, these things are taught to eleven year olds now at school so how hard can it be (joke) The thing is, to a programmer, the language that these picaxes use is Billy basic stuff, and they can write programmes with ease, so once a few of the brains on here realise that they can use these things to make dedicated brewing controllers, motor controllers, fridge controllers, disco light controllers, whatever...... then we will have circuits and programmes for us idiots on here to copy and use. What we need to build up on this forum is a set of tried and tested circuits and programmes, then we are all laughing all the way to the bank.
Having said that, I did knock up a simple circuit to act as an over temp warning on the coolant of my V6 engine. It had 2 temp sensors, a buzzer and an 08 picaxe chip. With a bit of messing about, I had a working circuit with a programme I had written! I was dead chuffed, but I know my limitations. It took me the best part of three weeks, and there are peeps on here who could do it in their head in say 5 minutes.