How can I prepare soy milk at home? Is it as simple as: soak soy, then blend and strain the milk, or is some centrifuge technique used?
It is basically as simple as you say (soak, blend, strain) ... just that you should also boil it (for long enough - cca. 10 minutes) to get rid of the fresh bean (grassy) flavor (mainly caused by oxidation of polyunsaturated oils in the beans), together with some other unpleasant side effects of eating uncooked beans (like the infamous gas-producing effect of some oligosaccharides).
There is a vast number of soy milk preparation instructions online ... this one has always worked really well for me: http://justhungry.com/milking-soy-bean-part-1-soy-milk with all steps and techniques described in detail, and you will also find some continuing posts on how to further turn it into tofu, if you wish so.
Depending on further processing steps and your personal preferences you might choose one recipe/preparation method over another, so I will not recommend any specifics, but in general this should set you on the right track.
p.s. I found that straining/squeezing through cheesecloth/cotton muslin/nut milk bag over a colander is a winning technique ... no need to go any fancier.
This is the procedure passed down to me thro my mom.
Let's say we are using two quarts of beans.
Ensuring the purity of texture and taste.
Producing the pulp
Squeezing out the milk
Two passes of squeezing