# Thread: Lini-Stepper Revisited ( Hacked )

1. The file Sstepper4-7.asm.txt‎ is a wave drive piece of code, thats all.

2. Originally Posted by student1616
at first i think of same.but micro stepping works.i tried and i can see the change in stepping pattern(imean microstepping) i have no idea how it works :-)
but the only problem i felt is current regulation and mosfet burn out.if i can solve these 2 issues,i can give full results.
and i think ur right kreutz.may be PIC is not switch on and off the mosfet completely.during microstepping that's why they are blowing out.

and what abt current regulation.how to calculate the current limiting resistor value
One way you can see micro-stepping in action is by using a fixture similar to my micro-stepper accuracy test fixture, a laser pointer mounted perpendicular to the motor axle and on its center, and projecting the laser light about 10 feet away. Otherwise you would not be able to discern them from a 90 degrees of a full step (0.045 degrees mechanical) or a complete full step (1.8 degrees mechanical on a 200 full steps per rev stepper motor).

A full step sequence is made of 4 movements, hence the 0.045 degrees per movement, if you are able to discern finer than that (micro-stepping) without an instrument, you really have an exceptionally good eyesight. Congratulations!!

The current limit resistors' value is calculated the following way:
R >= (Vps - Vmotor)/Imotor

Resistor power rating calculation:

P >= 2*(Imotor * Imotor * R)

Where P = resistor power rating in watts, use next commercial value equal or higher than the calculated value.
Imotor is the maximum specified current for your motor
Vps is the power supply voltage
Vmotor is the specified motor winding voltage
R is the value of external resistor in ohms, approximate to the nearest commercial value equal or higher than the value calculated.

You could use 2 resistors (in series respectively to the center tap of the phase windings for 6 wires motors) or 4 resistors (one respectively in series with each coil winding for 8 wires motors).

My 2 cents: if you are doing this for learning , please, continue spending money on parts and further experimentation. I also advise to read more about stepper driving at: http://www.cs.uiowa.edu/~jones/step/ in order to understand what you are seeing. If you want real micro-stepping results, please, use the original lini-stepper schematics and give it a try, you already have half of the parts for it.

3. Thanks kreutz
thanks for the detailed resistance calculation.

and i placed a clip over my motor shaft.(which is 3'' in length) to observe microstepping.
it might not be correct.but i can see the difference between full stepping and other micro stepping modes.and i used both 7.5 and 1.8 degree motors for this trial.

and as i said before original linistepper is sure a GEM.i also build the posix version for my small mill and still its working like charm.thanks guys..
mean wile i am just looking around and trying to build other controllers too(particularly with micro stepping)

4. Originally Posted by student1616
...... i am just looking around and trying to build other controllers too(particularly with micro stepping)
Well you can also check the following links: www.pminmo.com and
http://mardus-kreutz.blogspot.com/ if you want to learn a little more about other DIY micro-stepper drives.

5. ## help me

i have bild stepper driver using pic 16f84a & 122 transister for 12v stepper motor .
but i have 90v ,5A stepper motor any one can me send good idea to bild 90v ,5a stepper motor driver

thanks

6. Hi All
Has anyone thought of making up some of these (hex code debugged) for sale?
What will 3 cost?
Full step will give me a resolution of 0.01mm which for my needs is sufficient.
(its a hobby machine lol. who needs micron resolution?)
I tried to diy drivers but all I got was expensive smoke - no more for me.

7. Originally Posted by aubrey
Hi All
Has anyone thought of making up some of these (hex code debugged) for sale?
What will 3 cost?
Full step will give me a resolution of 0.01mm which for my needs is sufficient.
(its a hobby machine lol. who needs micron resolution?)
I tried to diy drivers but all I got was expensive smoke - no more for me.
It's all available at http://www.linistepper.com

8. ## Thanks

Thanks James
See you also have the gadget that goes between them and the pc.:
I just had a quick look but will check out the whole site over the weekend.
All the best
Aubrey

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