Just took apart a Canon LIDE scanner and am trying to identify the motor. Being a scanner, one assumes that it is a stepper, but beyond that, how can one tell if it is a unipolar or bipolar motor? I searched online for image references to differentiate but couldnt come up with anything.
Beyond that, is it possible to control this with the arduino without an intermediate driver? Checked the libraries on the arduino site and they seem to indicate the need for a "H-Bridge" (bipolar) or a "Darlington" (unipolar) . Is there any work around for this, or why is it necessary?
And forgive this last simple question: alot of posts say it is best to have an external power supply for the motor, but also that too much power will fry it. What would one use to modulate the power being fed to it? I mean this in the simplest way: in my mind, external power supply means hooking it up to a 9v battery or simply plugging it into the wall (this sounds like a bad idea...)
First step would be to find the continuity between the four wires. That should break it into two pairs (two coils).
If the resistance in each pair is 125 ohms or more (5V / 40ma max per pin = 125) then you can drive it directly from the Arduino's pins. If not you'd need to set up a basic transistor circuit so you can use more than 40ma or add a resistor to one of the lines of each of the coils.
The Stepper library would handle the rest for you. If the stepper doesn't turn properly then reverse the connections for one of the coils.
