Hi Prof,

On the electronics side of things :-

As your motors are only 600mA and 800mA I think they would get hot if they are drawing 10Amps.
Yes you do need current limiters.

The formulas you need are:-

E=I x R and W=V x A

so at 12V, 600ma a series resistance of 20ohms, 7watts would be required and for 12V, 800mA a series resistance of 15ohms, 9watts would be required.
As high wattage resistors are relatively expensive Tom has used bulbs in his design, which is what I suggest you use.

Hope this helps,

Tweakie.

Dear sir
              Please send me the circuit diagram for the stepper motordriver circuit for the 3 axis interfceable with mach3, and alos please send me the component list and their numbers, let me know what will the maximum RPM of the steppers. send me the circuits immediately. My email : rsrikrish1984@gmail.com.

Thanking you

Srikrish R

I am going to use the McGuire Stepper Motor Driver, but I am going to be adding quite a numer of LED's so I can see the inputs, outputs, switchs all working.
 
Here is what I have come up with so far: Stepper Motor Driver Board (1).
 
Both the printer port outputs on my PC and my Laptop go high once windows is loaded, but as soon as the Mach3 Software is loaded they are pulled low, Witch is good, I know the Mach3 software can be setup to rest at Low or High, so that is all fine.
 
Can someone have a look at the way I am driving the LED's and tell me if I am doing it right?
I in my design I am using BC547 and BC577, I don't know if there is better suited transistors for driving the leds.
 
With regards to the switches for the limit and home switches, It is safe for the switches to pull to ground or is it best to put a resistor inline, and if so what rating.
 
Thanks for your time.
 
Best Regards.