Hi all, I have a project that uses a stepper motor to control the focuser on a telescope, this is connected to astronomy software via a PC and is used to focus a digital camera for long exposure astrophotography.
The current version uses a 12v, 5 wire unipolar stepper motor driven by a ULN2003 which is controlled by an Atmega 328. Unfortunately as the stepper motor is geared its quite slow so I want to replace it.
I have a replacement stepper motor: the MY3002, the first one in the list.
http://www.astrosyn.co.uk/docs/mini_hsm.pdf
from the maths it's a 3.3v, 0.95a, 3.4Ω per phase unipolar stepper.
As far as I understand things, I can't use the uln2003 as it cannot provide the full 0.95a current that the motor could use.
I also have an L293B and an L298N that I can use, again I don't believe the L293B can handle the 0.95a draw from the stepper, so that really leaves me with the L298N.
Am I correct in thinking that if I want to use the L298N I would have to wire the stepper as a bipolar stepper?
If that's correct, how do I deal with the phase resistance of the windings and power resistors to limit the current?
Lastly where do the resistors go in the circuit? Ignoring the common wires as they're not used in a bipolar configuration, do I use 1 resistor per pair of wires?
Regards,
Reggie.
The current version uses a 12v, 5 wire unipolar stepper motor driven by a ULN2003 which is controlled by an Atmega 328. Unfortunately as the stepper motor is geared its quite slow so I want to replace it.
I have a replacement stepper motor: the MY3002, the first one in the list.
http://www.astrosyn.co.uk/docs/mini_hsm.pdf
from the maths it's a 3.3v, 0.95a, 3.4Ω per phase unipolar stepper.
As far as I understand things, I can't use the uln2003 as it cannot provide the full 0.95a current that the motor could use.
I also have an L293B and an L298N that I can use, again I don't believe the L293B can handle the 0.95a draw from the stepper, so that really leaves me with the L298N.
Am I correct in thinking that if I want to use the L298N I would have to wire the stepper as a bipolar stepper?
If that's correct, how do I deal with the phase resistance of the windings and power resistors to limit the current?
Lastly where do the resistors go in the circuit? Ignoring the common wires as they're not used in a bipolar configuration, do I use 1 resistor per pair of wires?
Regards,
Reggie.