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***For Support on this Project, Please use the forum on my website. Just go to http://colvins.ca and click the forum link on the side bar.***
I am 14 I have always wanted to build a cnc machine but because inexpensive parts are hard to find in Canada I have had trouble trying to build a decent cnc controller. The purpose if this Instructable is to show that anyone can build a cnc controller using an old scanner. The scanner I used was an old OpticPro scanner. I had previously extracted the stepper motor and experimented with it but not considered it for a cnc controller. All of the controllers on the Internet had a large number of expensive transistors or were ridiculously complex. I finally stumbled across this controller and realized I could build it. By reusing the parts from the old scanner and making the case from recycled cardboard, I am cutting back on my impact on the planet. Also, because this controller is so simple, it only needs one power suply, so, it only needs 1 12 volt (for both the logic and the motors), instead of 1 5volt (for the logic) and 1 12 volt (for the motors). This saves energy, especially when you run it for a long period of time.
If you don't already know what a cnc machine is, it is a machine that uses special motors called stepper motors to moce an object a percise distance. The difference between a stepper motor and a regular DC motor, is that stepper motors "Step", not spin. if you don't understand, refer to this artical. There are two types of stepper motors. There is Bipolar, and Unipolar. Bipolar motors have 4 wires. Unipolar motors can have 5, 6 and 8 wires. The difference between these two types of motors is that unipolar motors have 4 coil inside that, when energized in a certain order, allow it to step forward and backwards. This makes them easy to control and is why we are going to use them in this instructable. Bipolar motors only have two coils that can be energized in forward, or reverse. To drive a bipolar motor you need two H-bridges. Because of this, bipolar motors motor controllers are much more complex.
***For Support on this Project, Please use the forum on my website. Just go to http://colvins.ca and click the forum link on the side bar.***
I am 14 I have always wanted to build a cnc machine but because inexpensive parts are hard to find in Canada I have had trouble trying to build a decent cnc controller. The purpose if this Instructable is to show that anyone can build a cnc controller using an old scanner. The scanner I used was an old OpticPro scanner. I had previously extracted the stepper motor and experimented with it but not considered it for a cnc controller. All of the controllers on the Internet had a large number of expensive transistors or were ridiculously complex. I finally stumbled across this controller and realized I could build it. By reusing the parts from the old scanner and making the case from recycled cardboard, I am cutting back on my impact on the planet. Also, because this controller is so simple, it only needs one power suply, so, it only needs 1 12 volt (for both the logic and the motors), instead of 1 5volt (for the logic) and 1 12 volt (for the motors). This saves energy, especially when you run it for a long period of time.
If you don't already know what a cnc machine is, it is a machine that uses special motors called stepper motors to moce an object a percise distance. The difference between a stepper motor and a regular DC motor, is that stepper motors "Step", not spin. if you don't understand, refer to this artical. There are two types of stepper motors. There is Bipolar, and Unipolar. Bipolar motors have 4 wires. Unipolar motors can have 5, 6 and 8 wires. The difference between these two types of motors is that unipolar motors have 4 coil inside that, when energized in a certain order, allow it to step forward and backwards. This makes them easy to control and is why we are going to use them in this instructable. Bipolar motors only have two coils that can be energized in forward, or reverse. To drive a bipolar motor you need two H-bridges. Because of this, bipolar motors motor controllers are much more complex.
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Signing UpStep 1: Required Parts
The parts that are required for this project are:
In the scanner:
-1 stepper motor
-1 uln2003 chip
-2 steel rods
For the enclosure:
-1 cardboard box
The tools:
-Hot glue gun and glue
-Wire cutters/strippers
-Scissors
-Soldering tools
-Paint
For the controller
-1 DB25 port (recycled from previous project)
-some wire
-1 dc barrel jack (recycled from old RC car)
For the test rig
-1 threaded rod
-1 nut to match your threaded rod
-various washers and screws
-scrap wood (recycled from previous building projects)
For the control computer:
-1 old computer (I used an old laptop)
-1 copy of TurboCNC (get it here)
In the scanner:
-1 stepper motor
-1 uln2003 chip
-2 steel rods
For the enclosure:
-1 cardboard box
The tools:
-Hot glue gun and glue
-Wire cutters/strippers
-Scissors
-Soldering tools
-Paint
For the controller
-1 DB25 port (recycled from previous project)
-some wire
-1 dc barrel jack (recycled from old RC car)
For the test rig
-1 threaded rod
-1 nut to match your threaded rod
-various washers and screws
-scrap wood (recycled from previous building projects)
For the control computer:
-1 old computer (I used an old laptop)
-1 copy of TurboCNC (get it here)
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spread over 8 lines , and change "last phase" to 8 (like you did with the four from the instructable), you will double the resolution, without doing anything else!
Does anybody know is it possible to adapt this circuitry to work with hybrid motors?
Because they draw current way to much.
I have tried putting light bulb in series on the ground then it gets really weird.
After first jog with turbocnc light bulb lights up then it wont stop even without jogging.
ES MAS FACIL BUSCARLOS EN IMPRESORAS DE PUNTO, ESTAN CERCA DE DONDE ESTA EL CONECTOR DEL MOTOR PAP, SON 2 CHIP FACILES DE RECONOCER YA QUE ANBOS TIENEN LOS MISMOS NUMEROS EN LA CARA VISIBLE.
EN SCANNER NO HE BUSCADO PERO DEBERIA ESTAR CERCA DEL CONECTOR QUE VA HACIA EL MOTOR, PUEDES BUSCAR LA EQUIBALENCIA EN INTERNET, GOOGLE, ESCRIBES EL DATO DEL CHIP QUE SACASTE Y AÑADES DATASHEET Y TE MUESTRA LA PAGINA CON DATOS DEL CHIP. ESPERO QUE TE SIRVA
I recommend looking for the ones that have parallel or centronix ports on them. Possibly SCSI, too. The older ones were not small and you can easily see the "guts" and make you decision about its usefulness to you. Anything that has USB is probably going to have very little you want. They tend to have very small stepper motors and might be bi-polar. The exception being some of the UMAX Astra scanners that have parallel and USB. I also noticed the older ones tend to have really thick hardened steel rails. An added bonus for linear motion.
You can see a simple 1 axis version implemented like that here.
And thus the transistor that turns "on" first will take the full current load unless some sort of regulation is supplied to assure that each transistor in the array is "exactly the same"....
And to be truthful, I don't think there's any way to do that as the base leads to each transistor in the array are internal.
This circuit is good for 500ma per phase and there's a lot of small surplus nema 17 and nema 23 stepper that can be used with this circuit, but a lot that can't.
For those that can't, instead of using the ULN2003/ULN2803 just use a set of 4 TIP120's or TIP142's instead of the ULN chips.
look at these links for an idea of how this works and what your ratings will be:
http://www.luberth.com/plotter/TIP120schematic.png
http://www.luberth.com/plotter/tip120pcb.htm
http://www.ebay.com/itm/3-x-ULN2003-ULN2003AN-2003-ARRAY-7-NPN-DARLINGTONS-IC-/250853356024?_trksid=p5197.m1992&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D14%26meid%3D889391569064097534%26pid%3D100015%26prg%3D1017%26rk%3D1%26#ht_1497wt_799
please tell me .if i connect it to my computer do not burn my computer processes? because of feedback of electrical current form motor .
or any dangerous on my pc?
Hope this helps
Thank you very much
One other thing, the port monitor numbers the port pins differently than you have here, and my X axis seems to run on pins 2, 3, 4, and 5. Sorry if that's too much to address.
disconnect one two of the four wires and reverse them and try it again
http://www.instructables.com/file/FZ0WAKRGT19NJTB/?size=ORIGINAL
From the page:
http://www.instructables.com/id/Parallel-Port-Break-Out-Board-BOB/step3/Whyd-You-Make-it-This-Way/
Which should have been in my image library but having looked through it a half of a dozen times I'm a bit tired of that now. So those links will have to suffice. Fire the webmaster! Or more fitting in this case, web disaster.
The riser cable is of course the flat gray ribbon cable plugged into the printer cable.
how can i use the CNC version to drive a bipolar motors ? can i do that ?
thank you , great work
http://www.pololu.com/catalog/product/1182
Even my drivers own it handily:
http://www.instructables.com/id/TB6560-Microstepping-Bipolar-Chopper-Stepper-Motor/
Though with built drivers so cheap not worth the trouble building.