How can I know when my yogurt is ready (in a generic, basic, non-us yogurt maker)?
According to http://www.wikihow.com/Make-Yogurt, you can you tell if your yogurt is ready by "gently jiggling one of the containers . . . the yogurt will not move if it is ready and you can take it from the yogurt maker and put it in the refrigerator then. Or you can wait and let it get more tart for 12 hours or more."  It also gives more specific instructions about the three types of yogurt makers, so you can see which one you own and follow more recommendations based on that.