The project I am working on is basically a 2-axis positioning system mounted vertically. It requires two stepper motors for the x-axis so they will both be moving at the same time. The z-axis stepper will therefore move independently from the other two.
Bearing in mind I have VERY little arduino experience and NO experience using steppers before, is there a single stepper motor driver that would suit this or would I need multiple?
Well perhaps a ULN2803 could be used for each motor, two channels per motor lead for better current
handling. You'd lose some volts so a 7.5V supply would make sense. But that's assuming unipolar is
the way to do things, which I don't really buy into.
As its a six wire motor it might make a lot more sense to use it bipolar, in which case its a 15 ohm
0.55A motor, needing perhaps 18 to 24V to run well with a DRV8825 or similar.
Can I ask why not pick a motor more compatible with DRV8825 modules (ubiquitous these days, any
low impedance bipolar stepper upto about 1.5A will work well with them). A lower resistance motor
will work better (torque + speed) from 12V supply that a high resistance motor.
DRV8825 and similar motors only need two pins from the arduino to control them, the ULN2803
unipolar method requires four. With several motors the pin count soon adds up.
MarkT:
Can I ask why not pick a motor more compatible with DRV8825 modules (ubiquitous these days, any
low impedance bipolar stepper upto about 1.5A will work well with them). A lower resistance motor
will work better (torque + speed) from 12V supply that a high resistance motor.
So what decides whether or not it is compatible? Is it just the bipolar/unipolar setup and the voltage and currents values? I found these bipolar steppers on eBay that look a bit more promising;
They don't provide the torque-pulse curve but the stated holding torque is ≈2x the torque I require from each motor so I was hoping that they would do.
These are rated at 1.5A, will these be okay with that driver as I am unlikely to use them at full power?
MarkT:
DRV8825 and similar motors only need two pins from the arduino to control them, the ULN2803
unipolar method requires four. With several motors the pin count soon adds up.
Still a bit confused with the driver.. would I need multiple drivers or would this be able to drive all three of the steppers?
Thanks for your help and sorry if this stuff it really basic!
