Ive drawn the schematics for a cheap unipolar driver but capable of driving high ampere steppers, because I got some 1'3V/3'9A steppers and there is no real schematic able to drive that amount of current. I've built and tested with Master5 at a P266 with w98, an old PC-AT PSU and:
- Surplus unipolar Nema23 1V3/3A9 unknown torque
- Surplus unipolar Nema34 1V2/4A8 unknown torque
and variable satisfaction the nema23 has good 'tactile' torque and moderate speed, nema34 very good 'tactile' torque at low rpm.
Credits to the idea to www.cnconabudget.com
and this thread: Upping the capability of a 5804 IC
Next steps will be triying to add some current control IC to avoid RBallast.
Now, for the schematic:
- Wired for LPT pin2 Direction, LPT pin 3 Step, repeat for other axis (pin3&4 for Y, pin 5&6 for Z) or rewire for other pins as needed
- Wired for outputs always enabled
- Use Steper Calc (credits to Eric Van Andel) for Value of Rballast