I tried a couple using a mechanical timer as the motor, for one complete rotation per day. In the end I gave up because it was tricky to exert enough pull/push to get the tubing pinched closed, but not too much to overwhelm the timer. Plus it wasn't very adjustable, just enough for adding concentrated micros to a smallish tank.
You need a little high-torque motor. This is where the cost side comes in... good if you have access to them. If not, I'd agree with majstor... might be more cost effective to go with the relatively inexpensive APT pumps.
to get your creative DIY juices flowing...