Linistepper - cheap unipolar microstepping driver

[lietuvys]

Hi all,

recently I found stepper controller Linistepper which called my attention.

What do you think about it?

I am interested in running three unipolar steppers at currents about 3-5A per phase. I will use them for wood router. Currently I have build chopping controller based on L297 with FETs. I would like to drive my steppers at faster speeds with more torque. I think that Linistepper controller would eliminate resonance problems while using microstepping.

I see that it will be necessary to modify Linistepper - place more powerfull transistors, resistors and tune it up... I have skills and work with electronics, and want to do it myself. I have a scope which will be useful there.

Maybe someone allready done this?

Am I going right way? I know gecko drives, but they are too expensive for me now.

[drk]

HI ,

I must say its a great find. Ive been looking for something of that sort myself, and yes , geckos do work out quite expensive..

Also, have you posted gerber files of your drive??

Regards

Dev

[lietuvys]

Originally Posted by drk ... Also, have you posted gerber files of your drive??

No, I wired everything on proto board because I was just experimenting.

[James Newton]

Originally Posted by lietuvys Hi all, recently I found stepper controller Linistepper which called my attention. I think that Linistepper controller would eliminate resonance problems while using microstepping. I see that it will be necessary to modify Linistepper - place more powerfull transistors, resistors and tune it up... I have skills and work with electronics, and want to do it myself. I have a scope which will be useful there.

I sell and support the Linistepper in the USA. Just wanted to note that it IS an open source design: Although we do sell a PCB and a full kit with a pre-programmed micro controller; the circuit, source code, and PCB layout are all on the web site for anyone to see.

Linear drivers are very good at elminiating resonance and related issues. The motors run cooler (although the controller runs hotter) and turn smoothly.

The kit (or standard components) should work for up to about 1.5 amps per phase and 3 is very doable with a little fine tuning and... and REALLY big heat sink on the controller! 5 amps is really pushing it.

If you were just doing full step or half step, the higher power requirements would be easy, but the combination of microstepping and high power is difficult to do at low cost.

One thing I should mention is that we are doing a promotion for a limited time: If you purchase a kit or set of kits, build then hook up to your device (mill, lathe, telescope, etc..) and send me a picture of it (clearly showing the Linistepper) I will refund $10 of your purchase price. I will refund an additional $10 for a picture of any item showing the difference between linear microstepping and any of the standard stepping modes. The second refund is only available after the first has been qualified. It can be a picture of two items made by your device or, if you are using the linistepper to control a telescope mount, it might show the difference in clarity between two identical long exposure photos of the stars. Finally, a third $10 refund, available after the first two have been qualified, is offered for temperature readings of the motor and controller after 1 hour of operation in full step mode and again after an hour in linear microstepping mode.

Then end result is that, at least for one channel, the controller will be totally free.

[H500]

I like to commend the designer for coming up with an interesting and creative solution.

But as his website clearly states, this is not a chopper drive, so it's really not suitable for high voltage and currents. For example, if you need 4 amps per coil with a 55 volt power supply and 3 axis, the driver would generate as much heat as a 900watt heater! You will need a jet-like fan to keep it cool.

So the bottom line is, this is an interesting drive for those looking for a very low noise drive for relatively small motors. But it is not a serious choice for those who are looking to handle more current and voltage.

[James Newton]

Yes, the linistepper is good for up to 1.5 amps per phase in microstepping mode (or up to 3 amps per phase in full or half step ) and does best for small, precise applications or where smoothness is critical.

The heat generation that H500 warns about is generally valid, but perhaps a bit over stated... Not all the power is turned into heat. Not every step results in the driver working in a linear mode. etc... But yes: It does run quite hot in microstepping modes.

[posix]

Hello there James.

C5 and C6 are 2.2uF on the schematic, however you provide 4.7uF in your kits. Also Q5-Q8 are BC337 on the schematic yet you show TO-92 in your kit. Which one is the correct component?

Thanks

P.S. as far as those pictures are concerned, you'll get them from me when I'm done making the PCBs - laying out and routing this tiny board on a single layer takes time with eagle

[James Newton]

Originally Posted by posix Hello there James. C5 and C6 are 2.2uF on the schematic, however you provide 4.7uF in your kits. Also Q5-Q8 are BC337 on the schematic yet you show TO-92 in your kit. Which one is the correct component?

Those components are not critical and so either is correct. The values shown on the schematic are "ideal" but the components supplied with the kit work perfectly and happen to have been easier to source.

BTW: TO-92 is a case size not a transistor type, and in fact the transistors supplied with the kit are actually BC337 in TO-92 cases. But the transistor is not critical and the standard 2n replacement for a BC337 could be used instead.

Originally Posted by posix P.S. as far as those pictures are concerned, you'll get them from me when I'm done making the PCBs - laying out and routing this tiny board on a single layer takes time with eagle

I'm looking forward to it!

[pminmo]

I added the linistepper link to my webpage if thats ok?

Phil

[posix]

Ok, It's done. But it doesn't spin. I did for a brief moment after a lot of re-wiring attempts (and helping it along by hand). Now it just wobbles again. I also get around 6v on Q1 and around 11v on Q2,3,4.

When on 3600 mode, full power (111) it does 4 steps (as far as I can "feel" under my fingers) to one side then 4 to the other. The time it spun the stepper it was on 200 mode i.e. full step, full power (100). I am still on the default 1ohm set-up. I have also incorporated the two 470ohm resistors found on the assembly page between +5v and r14/15 and r16/17 respectively. Everything is basically as per web page.

I'll experiment some more and report on progress.

P.S. just to get this straight (transistor->coil) Q1->A+ Q2->A- Q3->B+ Q4->B-, right?
P.P.S. my steppers are 1.2A step-syn items (blue label)

[James Newton]

pminmo: Heck yes that's ok, thank you!

posix: Sounds like a wireing problem. Check out http://www.piclist.com/techref/io/st...p/lini_use.htm and especially the section under Motor does not turn??

For help with how to find the wireing of a motor, see the expert script at: http://www.piclist.com/techref/io/stepper/wires.asp

I would recommend you stick to full step (200) until you get the motor turning then try the microstepping modes.

[posix]

no matter what I do it just wobbles and sits there. At some point in the frequency range it begins moving back and forth erratically then stops again and wobbles. I have downloaded the lini zip file, is that the correct software? I compiled it from source rather than re-use the existing hex file.

are you sure the schematic and software on the home page of linistepper are the glitch-free versions?

I am using an atx power supply which worked fine on another tip1220-based driver of mine so that side is ok.