Hi, I'm planning a project in which I control 12 water valves by using servos to, by a rubber band, squeeze plastic tubes to make them "on," or off. Besides the blinking LED's I'm pretty new to Arduino and circuit design. From what I understand, I can use two shift registers to individual control 12 servos, correct? Will I be able to do the pulse thing the servos require via the shift registers?
This would free up my Arduino to control a motor via a transistor, correct? I have read about using an hbridge to reverse the motor directions, and that I can build this with four transistors.
I have looked at a bunch of h bridge designs, and read about how it's dangerous to short them, but I still cannot figure out what is going on or how it is working for some reason. Is there also anybody who could explain this to me? I kind of get that two of the resistors I use flow in one direction, and these other two flow in an opposite direction, but I don't see how they all add up to make a circuit. When I am using either of the pair of transistors is electricity flowing through the circuit with the other transistors as well? Why is it the bottom pair of transistors that is connected to ground and not the top as well?
(I'm attaching an example of such an h-bridge as seen on robotroom.com)
Thanks for your help!