Motor Stepper Example

[astanapane]

That is really interesting.

I learn from you guys everyday. Thanks a lot.

New i only need to understand how To give a step and a direction at the same time

[HenrikOlsson]

Basically you don't.
You set the direction signal high or low depending on the desired direction, then you start sending out the step-pulses. You want to make sure the direction signal is in its correct state before the step-pulse goes out. If it's not the motor might move a step in the wrong direction.

[astanapane]

This sounds much easier than i thought.
Thanks:-D

[astanapane]

This morning i dissasembled the stepper Motor.

I found out that There are 8 magnets with 6 teeth magnets each.

That in the middle you can find the axis shaft with a gear which the 50 teeth slighty touch the outer magnets teeth.

That is interesting.

[HenrikOlsson]

Hi,
Actually, the magnets are in the rotor. The 50 teeths on the "gear" are alternating N/S poles of the magnets.
The stator contains the windings which, together with the iron teeths forms elctromagnets. By running current thru the windings the magnetic field developed eitther retracts or repells the magnet in the rotor. By changning the direction of current flow thru the winding the polarity of the magnetic field changes, kind of draging and/or pushing the rotor in either direction.

When the motor runs there will be a rotating magnetic field in the stator and the rotor follows this field. When the torque reaches a point where the rotor "lags" the rotating magnetic field too much it will "desynchronize", if the speed is high it will just plain stall. The good thing is that you can never destroy a step-motor by simply overloading it.

The rotor does not touch the stator at all, there's a VERY fins airgap between them. You should never open a step-motor in a dirty environment since, the magnets in the rotor are very strong and will "suck in" small metallic chips from your workbench which will end up in the fine airgap and either lock the motor up completely or make run "strange".

Depending on the type of magnetic material in the rotor it's also advised against removing the rotor from the stator as it can then loose some of its magnetism. Same reason why you have what's called a keeper-plate on "ordinary" magnets. With that said I've personally had several motors appart to drill holes thru the shaft and they have been working afterwards. I don't have anything to measure the actual torque but I couldn't "feel" any difference.

/Henrik.

[astanapane]

Henrik,

It is very kind of you for giving all these detailed info.

I completely understand now the principles of the stepper motor.

What i have done today is to design a Base as a jig and future, in order To Work easier.

My next design will be a circle with 200 pins that represents the steps. then from the motor's axis i will put a vertical pin that will follow the 200 pins on the outer circle.

At the moment the following Mode is completed.

[astanapane]

sorry for uploading pictures of the design, but would like before starting with the simple code, to give you a feeling of the jig and fixture model.

So what you see is a model that has 200 steps inside the circle, and 16 points outside (8 sharp and 8 with a hole)

Those can represent basic angles on a 360.

When i have them ready then i can start to right one or two lines of program to play with.

After that i will improve the code with your help

thanks a lot.