LiniStepper

Microstepping Stepper Motor Driver Kit

FAQ:

Questions:

• spamdbroadwellSPAM at SPAMgmail.com asks:

  I'm considering using the Linstepper for a azmith/elevation antenna project. For the elevation I have two motors that are mechanically in parallel and (hopefully) can both drive at the same time. As they are both mid size motors (of the same model number and rating 5.1V@1A) I was hoping to accomplish this with one linstepper and possibly changes to the driver transistors. Is this possible?

  James Newton replies: Sure. But it will require a solid understanding of electronics on your part.+

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• kenny_saltiel-comverse- asks:

  Hi,
  I purchased 2 boards and finished constructing the first one, which is bolted to a bracket and large heatsink. While testing with a 3.2v 2A stepper on my mill, the bracket seems to get too hot. I replaced the 1 ohm resistors with 0.5 ohm 10w resistors and am driving the board at 24v. Within about a minute, the bracket the transistors are mounted on, gets so hot I can't touch it with out getting burned.
  I have a 42cfm fan blowing directly on the heatsink but it can't cool fast enough. I'm afraid to burn out the board so I turn it off after 1 minute.
  While it is working (for that minute) it works perfectly on full-step and half-step. Haven't tested micro-stepping.
  Am I doing something wrong or is my setup too power hungry for this board?
  Thanks.
  

  Saltiel replies: I guess I'll answer my own question. As documented elsewhere on this site, the difference between the motor voltage and the supplied voltage is translated to heat. I experimented with lower voltages for my steppers, and it seems that 15v will be sufficient. At this voltage, the board remains cool with my heatsink and fan. Kenny.+

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• Mel Guevarra asks:

  hi all,
  
  i have posted this question on another page, and i am posting it here again.
  
  will the source code work with the newer PIC16F628A? anything that i should change in the source code. not a pic programmer myself, just a newbie. what do i need to change in the source code?
  
  also, can i use a 20MHz crystal instead of the 16MHz? do i have to change anything on the source code? if so what will it be?
  
  sorry for asking too much.
  
  thanks in advance.
  
  mel guevarra
  

  James Newton replies: The A is backward compatible so it should work fine. Since nothing is timing critical, the crystal should also be ok.+

  Mel Guevarra replies: hi! thanks then. at the moment i am populating my breadboard and will test it with a 555 as signal source like how you are doing things. will post on here the results. thanks again. mel+

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• spamcorradiniSPAM at SPAMyahoo.com asks:

  Hi! I just built the kit, with the 555 driver kit. I'm using it to (hopefully) drive a 6-wire linear actuator, which will slowly push a syringe pump. The motor is a Hurst SLS custom-jobbie I got from a surplus dealer here in Silicon Valley; the label says 12VDC, 11 1/2W (which, in my newbie brain, means about .96A; 12.5 Ohms...?)
  
  So - what are my power supply requirements/hookup? (Sorry, but I wasted my education on an MBA, and am mostly trying to learn chemistry lately - my EE knowledge is decades old....) TIA!
  Andrew

  James Newton replies: Motor power supply should be 2 to 3 times the rated voltage of the motor.+

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• I would aappreciate a little help. I intend to use a 2.7A motor, but is aware that tnhe the sense resistor cannot be lower than 0.66 ohm. I understand that R14-R17 has to be changed, and so do R18-29. Have tried various values, but it's it been really a shot in the dark. Could you be able to suggest some values are starting point.
  Thank you for your help and a agreat design
  
  Kind regards - Jock James Newton replies: You can use the form about half way down the page at http://www.piclist.com/techref/io/stepper/linistep/lini_tun.htm to find the sense resistor values to use for your target motor current. I'm a little confused as to why you feel the other resistors must be changed...+

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• spamdurljSPAM at SPAMcomcast.net asks:

  I am using a US Cyberlab Neuractor CNC-4+ kit that I built 10 years ago. My software is DANCAM. My motors/drivers are pretty whimpy. Do you know if your stepper driver has been used to retrofit a CNC4+ kit to provide better torque and speed? Thanks, Durl

  James Newton replies: Sorry, I don't know anything about that specific kit. What does it put out? What type and rating are the motors?+

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• asks:

  They say that there is no such thing as a stupid question, I say "Are they nuts"? Please clarify, can one linistep control multiple motors from one printer port? Futhermore, I just "ebayed" three (Hy200 Nema 34 170A8 1.7 amps) motors. I paid nearly $50.00 USA, is that a good price, and is that motor suitable for the linistep? Thank you very much for your help.

  James Newton replies: One lini per motor. I don't know, I pull my steppers from old copiers, printers, and fax machines. If it has 5 or more wires, it will work fine.+

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• spamcamdesignSPAM at SPAMgmail.com asks:

  The 1 0hm 3W resistors are for 1 ampere current limit. Is it nessecary to change these resistors when i want to use a motor with 0.6 current rating for one phase? Or can the driver with these resistors be used for any motor up to 1 ampere per phase?
  
  Steven from the Netherlands

  James Newton replies: I would change them.+

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• spamakrookeSPAM at SPAMntlworld.com asks:

  How large a stepper motor would you need to use to drive the steering gear of a small ship, producing about 400KNm? Sounds ludicrous I know, but I was just wondering.

  James Newton replies: It's a good question... Sadly, it is almost impossible to answer. There are so many things that affect the actual torque output of a stepper motor that estimates are useless. You just have to try and adjust motor size as needed. The actual torque or a specific motor/driver/power supply combination can be measured but is very difficult to guess.

  Take a look at the stepper page and the torque page for more general information.

  There is an automated tool at http://www.galilmc.com/support/motorsizer/index.html which proports to answer this sort of question. You put in system type, load mass, etc... and it tells you want motor and drivers to use. Does require registration. And that is specific to thier motors and drivers.+

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• spamjanroseSPAM at SPAMntlworld.com asks:

  http://homepage.ntlworld.com/janrose Hi to all! I'm very new to Pics, but have had excellent results so far with "burning" the 16f types, using source codes or hex files compiled by the experts "as is". The Linistepper looks fantastic to me, but I need some advise here. The project calls for a 16Mhz resonator. The Pic on the pictures seems to be a 10Mhz type. 1.Is this correct or am I misreading something?
  2. Instead of using a 16Mhz resonator, can I use a 10Mhz crystal instead? (Got some in hand).
  3.Most of all, I would like to use Pic 16f628, but of what freq? Does the source-code need modifying to suit? If so, what?
  Thanks for the patience.. Can somebody please e-mail me directly..Regards, Jan Huyser

  James Newton replies: 1. The kit is supplied with the correct part for the resonator. 2. A slower osc can be used, but the unit will have a lower maximum step rate. 3. I would expect the source modifications would be minimal.+

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• I have a question about the Linistepper. There appears to be no protection for the back emf generated by the motor coil when the drive is turned off. It appears to me that the voltage on the transistor collector will rise to a fairly high value and be in danger of destroying the transistor. Obviously this does not happen, perhaps the caps on the base drive limit the dI/dt sufficiently? I am curious if you have ever looked at the voltage waveform on the transistor collectors. If nothing else, the current would take longer to decay on turn off than if it were shunted with a reverse diode, or even better, a zener, that clamps the back emf to say 50V, before it can pop the transistor. This current would tend to reduce torque as it is opposing the rotor moving to the next position.
  
  By the way Linistepper is a great piece of work, how to do a lot with very little parts.
  
  TomH sarnidac{AT}bigpond{DOT}net{DOT}au

  James Newton replies: The caps do a very nice job of smoothing out the high voltage pulses and the remaining juice leaks off quickly.+

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• Jerry Foster asks: "Do you have a schematic for a 555 ckt that you know works with your board? Thanks." Yes, here it is, and we are working on a PCB / Kit for this circuit which should be available soon. Update: The 555 kit is not available

• spamgustavo_afonsoSPAM at SPAMig.com.br asks: " Is the circuit diagram at the linistep page revised? Can I make that circuit without worry? Regards from Brazil" James Newton replies: The sense resistors are usually customized for your motors and application. There was also a minor update that is detailed in the "how to build it."+

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• The instructions for the LiniStepper kit refer to a 16Mhz resonator. I didn't think you could get a 16Mhz version of a 16F84.
  
  Also the instructions show 2 what the text refer to as 470 Ohm resistors but on my screen look like 47 Ohm (yellow, violet, black) and are not shown on the circuit diagram.
  
  Yours Perplexed
  Chris
  cjudge@globalnet.co.uk

  James Newton replies: The LiniStepper kit supplies a 16F628 (or compatible) chip which is rated to run at 16Mhz. While the source code can be re-compiled for the '84, it would need to run at a lower speed or be "pushed" (which is not recommended).

  In the picture, the brown does look a bit black, but they are 470 Ohm resistors. They were added to improve operation and tolerance for component variation after the design was complete and the boards produced. They are important, and will be incorporated in the next revision of the design.+

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• spamanthony05SPAM at SPAMearthlink.net asks:

  Thank you so much for the information on this site and contained in the links! My goal is to use my own program and printer port to control stepper motors. If I use your linistepper boards do I have to worry about Electro Magnetic Feedback from the motors going into my PC? Also, if I used my PC, then would this eliminate the need for a separate timer?
  

  James Newton replies: You should ALWAYS worry about spikes and so on going back into your PC. Especially with high power connections like this one. A good opto-isolated IO board would be nice to have, although I've found them to be very expensive. I personally use an old '286 computer that I really don't worry about frying for all my experiments. People are giving them away all the time.

  I am working on a PC interface board with some very low tech, low cost optical isolation for the hobby market and I hope to have something ready soon. For now, just be careful.

  And yes, your PC can be used as a timer by sending out pulses from the parallel port. Your accuracy may not be perfect, but it should get the job done.+

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• spambobSPAM at SPAMbnbbooks-plus.com asks:

  Hi, I was wanting to use your driver for a PCB router project. I thought I would use 80 oz/in motors. Do you forsee any problem with this idea. And, also, can you recommend a good source for stepper motors. (Preferably, for poor people.) Thank you for your assistance.

  James Newton replies: You really need to look at the amp/phase rating of the motor rather than the torque.

  Industrial Junkyards and office equipment repair shops are the best Stepper Motor sources I've found +

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• how much will the 3 axis kit cost me to ship to the uk?

  James Newton replies: The USPS website says shipping to the UK costs $6.40, plus $7.50 for registered mail (which I have found is necessary to prevent "accidental" loss of things in customs) and another $1.75 for a return reciept. Both our addresses have to be written on each of those and on the customs form (that is 4 copys of exactly the same data... yes, it is a government agency) so I get another few dollars for my time.

  Short answer: $20 shipping and handling to the UK (and most other places).+

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• With regard to my question below, I've done a big more research and found that I'm going to need around 160 in. oz. of torque. Haven't been able to find such high torque steppers that are around 1A/phase - do they exist?
  
  Also with the heat sink, I just realised that although I'll only be stepping the motor very rarely, the stepper motor will be holding its position for hours on end, so I presume there will some heat dissipation here.

  James Newton replies: That sort of torque is very doable... with a gear train. There is a low power hold mode, but yes, you really do need heatsinks.+

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• spamstebboSPAM at SPAMnewsguy.com asks:

  Hi,
  Your controller looks like what I'm after, but maybe you could verify. I'd like to control from a PC a roller-blind type projector screen. Rotational speed from the motor would only need to be somewhere between 2 - 5 rev/s, the rod for the blind (being 80" long) would be light and the screen a light material, so I assume a 1A/phase stepper motor would do the job. Would I be able to get away without extra heatsinking/fans considering I'd be only driving the motor continuously for 10 seconds, then nothing for hours (assuming optimal PSU)? Or is heat generated at idle?
  
  Thanks
  
  Simon
  

  James Newton replies: I aways like to err on the side of too much heatsinking rather than too little. Plan on the heatsinks, and if it never gets warm, cut down, but never elimiate them.+

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• spamkburdgesSPAM at SPAMmindspring.com asks:

  I want to drive a stepper motor at various speeds to a given number of steps, or until stopped by a signal. I have built the linistepper kit, but have to learn how to program the pic. Is it possible, or do I need to go to a more powerful processor?

  James Newton replies: Very possible. But learning to program a PIC may be easy or very hard depending on your experience. Try the PICList beginners page for good starting points.+

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• Jaime asks: "Will the motor get burned if I exceed the voltage rating but maintain the current limit..." Roman answers: No, the motor will be fine, but the lini will dissipate MUCH more heat. You will need a larger heatsink and fan. Unless you need very high motor speeds it's best to keep psu voltage as low as you can.
   
  Jamie asks: " I came across linear power supplies like 5V-6A and 12V-3A, would this be enough for the motor supply. Also their is also 5V-8A and 24V-7A but isn't this quite high for the 8.6V motor?" Roman answers: You need a PSU that puts out about 3v more than the motor voltage, with enough current to run 3 motors when all phases are on, ie 6x current. With your 8.6v 1A motors that means an 11.6v 6A psu.
   
• Wayne asks: " Inoticed the Lini software can be compiled for a Pic16F84, will the Pic16F84 work correctly?" Roman answers: I designed the linistepper to use my surplus stock of 16F84 chips for my own use. It can use a 16C84, 16F84, 16F84A, 16F627, 16F628 and some of the non flash OTP chips that also have 18 pins. :o)
   
• Tom asks:

  I am considering this controller for a project that will automatically guide a newtonian telescope. Could it smoothly control a motor down to 1 revolution per hour? Also, with all the heat, does it eat a lot of power? I would like to run a small stepper off of a 6v lantern battery.

  Sure, the linistepper can "smoothly" rotate a load at 1 RPM and it does not "eat a lot of power." Given a 200 step per revolution motor and microstepping at 18th over, you would have 3600 steps per revolution with a 1:1 connection. A 2:1 belt or gearing would give 7200 steps per rev. For even smoother operation, a fluid damper or flywheel mass would smooth the motion. Now, each step will be imperfect in size but *average* tracking will be perfect. See Linear stepping with the Linistepper or How smooth is smooth? for more information.
   
  If you REALLY need micropower, You would be better off with a DC motor and a good feedback like a quadrature encoder to close the loop and allow the precise positioning and rotation OR use a small stepper and turn the entire driver circuit OFF between each step so it only uses power while moving a step. The linistepper does not have an option to turn off the power, but it is an open source project, so anyone could try to add it. Both these micropower systems will require some clever engineering on your part. The easy suggestion? Just buy a decent sized lead acid battery and use a small stepper motor and a linistepper.
   
  I have run a small stepper motor from an old printer (under no load) for several hours on a 9v battery. A tiny 5v stepper motor from a modern floppy disc drive will run ok on about 100mA per phase, average 150mA, will give a few hours use from a decent sized 6v lantern battery. However a larger sealed lead acid battery will work MUCH better and is rechargeable. Your mileage depends on the load, the motor, the battery and the phase of the moon. I can only suggest that you try it. I'll accept the return of a WORKING unit for a refund less shipping if you find it isn't efficient enough.
   
  We are getting a lot of interest from the astronomy crowed, and I would love to hear back if this works... One point to keep in mind: The Linistepper expects step and direction signals from an outside source, so you will need a computer or a little clock "pulse generator" circuit to activate it. OR, since this is an open source project; the uController could certainly handel this internally if someone modified the code. 
   

• al lewis of fkb asks:

  Hi ref the LiniStepper v1. I take is as it has a pic that all the programing for running the stepper motor is programed on board. Could it therefore be used with a hand controller? I also have a 4 wire Bipolar stepper . How about that?
  Seasons greetings and thanks. al

  First, Unipolar only... your Bipolar motor needs a different driver. Second, since the project is open source, the code in the PIC could be modified to do other things, including (I assume) respond to a hand controller.
   

• spamatmelSPAM at SPAMxs4all.nl asks: " i wonder if it also works with the 16C84 type !!! " +
   
  Yes a 16C84 could certainly be used to send step, direction and other signals to the PIC on the Linistepper board, and if you are thinking about replacing our PIC with a 16C84... With some source code modifications, yes, it could work...
   
• spamgreywolfSPAM at SPAMvcn.com asks:

  How do you hook the motor to the Linistepper board?
  Does M+ connect to one end of each phase, or do you connect the center tap to the M+ terminal?
  
  thanks
  James

  Hi, with most common 5-wire unipolar motors;

  • find common "centre tap" using an ohmmeter
  • common goes to M+ power
  • other 4 wires are the phases

  With 6-wire unipolar motors;

  • find the 2 common wires
  • connect these together
  • connect commons to M+ power
  • other 4 wires are the phases

   

• spambimbo1SPAM at SPAMcenturytel.net asks: " can't get through with PayPal. Would you email your address and i will
  send a money order. Thanks marvin" +
   
  Sure!
   
• spamstan.stelmachSPAM at SPAMrogers.com asks:

  Very informative and interesting! I have one question regarding the kit for the Linistepper: the PIC chip is programmed already, isn't it? How to go about tools/info on programming these chips? Stan

  Thank you! The PIC is pre-programmed. You can find information about PIC device programmers at the PIC programmer page +
   

• spammd_christisonSPAM at SPAMhotmail.com asks:

  Hi, I'm a newbie and would like to know what it would take to drive the stepper motor board directly from the printer port--as in, does the software posted here do the trick directly, or do I need to figure out how to make calls to the printer port?

  Thanks for your time--it's very much appreciated!

  You are very welcome! The linistepper software is for the PIC on the actual controller board. Computer Numerical Control software for your PC will send signals to the parallel port to activate the controllers. See our CNC page for some options. The hardware connection is easy, just make sure the linistepper and the PC share a common 0v (gnd) and then connect the parallel port to the linistepper input pins. The resistors are already on the linistepper board. +
   

• spamcook8SPAM at SPAMadelphia.net asks: " How do I connect 2 or 3 board (motors) to the same printer port." +
   
  Answer: With our 4 Axis / mode control / +5 Power / 555 test / Relay board board, of course!

  In general, the Linistepper can listen to 5 signals. So, for example, you could connect a single Linistepper to the PC Parallel port like this:

  Port
  Pin  Axis  Signal
  ---- ----- ---------
  D0   1     Step
  D1   1     Direction
  D2   1     Power
  D3   1     Mode
  D4   1     Mode
  

  Which limits you to one axis per port. If you don't care about the low power hold mode, just wire that pin on the Linistepper to +5 and then you can get two axis per port:

  Port
  Pin  Axis  Signal
  ---- ----- ---------
  D0   1     Step
  D1   1     Direction
  D2   1     Mode
  D3   1     Mode
  D4   2     Step
  D5   2     Direction
  D6   2     Mode
  D7   2     Mode
  

  If you drop the low power hold mode, and run all the axis in the same mode, you can get three per port:

  Port
  Pin  Axis  Signal
  ---- ----- ---------
  D0   1     Step
  D1   1     Direction
  D2   2     Step
  D3   2     Direction
  D4   3     Step
  D5   3     Direction
  D6   All   Mode
  D7   All   Mode
  

  But normally, you will operate the Linistepper in only one mode which will be selected by wireing the mode and power connections directly to +5v or ground. This is the standard way that most stepper controllers are used.

  In a production environment, were the boards are being pushed to the limit, the low power hold can be very important. With the modes hard wired, the low power pins of all three axis can be controled from a port pin:

  Port
  Pin  Axis  Signal
  ---- ----- ---------
  D0   1     Step
  D1   1     Direction
  D2   2     Step
  D3   2     Direction
  D4   3     Step
  D5   3     Direction
  D6   All   Low Power
  D7   All   Free: Mode1?
  

  Note that this leaves one line unused. Connecting it to Mode1 would allow the system to switch between full or half step and a microstepping mode which could be useful for fast traversal when jogging, homeing, or otherwise moving without cutting.

  Each board (and stepper) really requires only two signals, Direction and Step. The other signals are for configuration of the operating mode can be supplied by manual jumpers. Each printer port has 8 data outputs (D0 to D7) plus some control signals. The standard way of connecting stepper controllers to parallel ports is like this:

  Port
  Pin  Axis  Signal
  ---- ----- ---------
  D0   1     Step
  D1   1     Direction
  D2   2     Step
  D3   2     Direction
  D4   3     Step
  D5   3     Direction
  D6   4     Step
  D7   4     Direction
  

  This allows for 4 axis control, and is the option supplied with our 4 Axis / mode control / +5 Power / 555 test / Relay board which really makes the entire thing very easy.

  If you need more there are two options: Install a second parallel port (for 8 axis) or combine direction signals.

  IF your software supports it, you can wire all the direction inputs to one parallel port pin so that the remaining pins are available to step other axis. The software needs to set the direction for the first axis, then pulse the ONE step signal for that axis and continue repeating this process for each axis. Obviously this takes longer but when you compare electronic signal speeds to the speeds of the mechanical world, you can see that it won't matter much.

  Port
  Pin  Axis  Signal
  ---- ----- ---------
  D0   1     Direction
  D1   1     Step
  D2   2     Step
  D3   3     Step
  D4   4     Step
  D5   5     Step
  D6   6     Step
  D7   7     Step
  

  So this would allow 7 Axis control from one parallel port.

  Actually, most of the software available for PC's will specify which Port Pin is to be used for what, or will allow you to specify in the software how you have connected the signals.
   
  Again, see out page on the parallel port pins for the actual pin numbers and pictures of the connectors.
   

• "Can I control this board from my computer with software like turbocnc running standard G code?"
  
  Answer: I only have a limited knowlege of turbocnc but one thing i'm sure of is that it will output standard "step and direction" signals. So the answer is yes. :o) There is more info available at the turbocnc page.
   
• "I want to run a higher torque motor(150 to 300 oz-in range). Will this board do it?"
  
  Answer: YES. Provided you choose motors that are rated at 1.5 amps per phase OR LESS and that give that torque AND they are 6 wire or 8 wire motors! (not 4 wire). When buying new motors you will have the option to choose motors that have differing amps ratings but the same torque. Just be aware that some suppliers try to push the "low inductance" motors that tend to be high amperage.
   
  Warner Electric make a suitable motor; KML091S02, 6wire, 1 amp/phase, 34 frame, 215 oz/in (don't expect it to be cheap!)
   
• "...how powerful of a motor can it drive? I need to drive some 1.5V - 5V @ 2.5amp-4.6amp stepper motors."
  
   If your motors have 4.6 amp on the label the stepper driver must be capable of that. Our stepper driver is only suited for small and medium sized motors, generally marked as 1 amp or 1.5 amp on the motor label.
   
  Your large 34-frame motors will work from our driver, but only at 1.5 amps per phase, which won't give you full torque if they require 4.6 amps per phase to get full torque. Large high-amperage motors usually require a more expensive driver, something like the geckodrive etc. Those big motors get real expensive. :o)
   

Bruce M. Stump Says: " Does anyone know if linistepper can be used to control coils sequentially at high speed for a homemade type linear motor " James Newton replies: Hi Bruce it sounds like you want a controller to fire coils in a linear motor? Yes the lini module can do that but you would probably need to re-program the internal PIC software to do it and even then it will only work for 4 (or less) coils. The max speed is determined by the software, since the PIC is crystal resonator locked you could program it to be the firing controller and you could fire the 4 coils in sequence at a very high rate, about 2MHz i think. You might want to look at the 4017 logic chip, this accepts a simple clock input and drives TEN outputs in sequence. It can do the high speed you need and you just need up to ten transistors for your coils. For best results do a search on ("linear motor" controller) as there are commercial modules. -Roman :o)+

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Comments:

• spambhaguanSPAM at SPAMgmail.com

  Hi all,
  Kai Ries, if your there, I would love to see the code for your alt-az telescope controller!
  I can find no link to it :(
  Please do post a link here if you wish to share it, you will save me and many others days of head scratching !
  Many thanks,
  Dylan.

  James Newton replies: http://www.piclist.com/techref/io/stepper/linistep/mod-maxries.htm+

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• spammark.phillisSPAM at SPAMntlworld.com

  Hello
  I am looking for controlling a stepper motor in 1 or 3 degree stepps.This is for a Comparater dial for my master clock.The stepper would recieve 1 sec and 30 sec pulses from a master clock.The idea of this is to show the differance between master clock time and frequency time.The stepper would go clockwise with frequency and anti clockwise with master time and the dial on the stepper would show the differance between the two.I first have to find away for the stepper to move the 1 or 3 degree from the pulse from the master.
  Any help would be great.
  Regards Mark

  James Newton replies: The Linistepper will NOT do what you want. It needs step and direction signals.

  However, the Linistepper is based on a PIC Microcontroller and it is open source. So, you could reprogram it to accept the signals you need. Or an experienced PIC programmer could anyway.+

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• spamries0037SPAM at SPAMplanet.nl

  Hi!
  
  I'm very confident about the linistepper! I made two of them on one board, for driving two floppy drive steppers. It is for use of a dual axis telescope drive (1:3000 gear ratio). I have modified the firmware to support only the microstepping mode and your special halfstepping mode. Microstepping is very accurate and what is more important, there are absolutely NO vibrations, which can be even more distracting than rough step sizes. For controlling the stepper board, I have made a very simple controllerboard, based on an 16F84. It operates the two motors independantly and is also able to be controlled by RS232. It is adapted to be used for a altazimuth telescope. However, it could be interesting for other standalone operations as well.
  
  Kind regards,
  
  Kai Ries
  
  

  James Newton replies: See: http://www.piclist.com/techref/io/stepper/linistep/mod-maxries.htm for Kai's modifications.+

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See also:

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