Bipolar Step Motor Driver: Difference between revisions

Jump to navigation Jump to search
no edit summary
mNo edit summary
No edit summary
Line 1: Line 1:
This is the wiki page for the Stepper Driver that [[User:Traylerphi|TP]] is working on.
This is the wiki page for the Stepper Drivers that [[User:Traylerphi|TP]] is working on.


This project is a sub-project of [[DIY CNC Router]].
This project is a sub-project of [[DIY CNC Router]].
Line 7: Line 7:


== Background ==
== Background ==
Being a form of brushless motor, stepper motors require that their windings are charged in a particular sequence with particular polarities.  A motor driver is an electronic device that uses logic signals from a controller to connect the winding(s) of a motor to a power supply.  The logic signals from the controller determine how and when connections are made, although some drivers simplify the interface out to the controller to only step (frequency controls speed) and direction (CW or CCW).  For the 50Ω bipolar stepper motors we need to drive, this boils down to two full H-bridges that can handle 12V with current spikes up to 400 mA, with an emphasis on minimum component count.
Being a form of brushless motor, stepper motors require that their windings are charged in a particular sequence with particular polarities.  A motor driver is an electronic device that uses logic signals from a controller to connect the winding(s) of a motor to a power supply.  The logic signals from the controller determine how and when connections are made, although some drivers simplify the interface out to the controller to only step (frequency controls speed) and direction (CW or CCW).  For the 50Ω bipolar stepper motors we need to drive, this boils down to two full H-bridges that can handle 12V with current spikes up to 2A, with an emphasis on minimum component count.


== Phase I ==
== Phase I ==
Line 22: Line 22:
The EasyDriver boards cost about $15 each (plus S&H).  I'll be trying to design a board that can be built for less than $30 to drive all the motors we need for the project.  The hope is to design something that can be incorporated into a kit we can call our own while being reasonable for another Hackerspace to use or even replicate from scratch.
The EasyDriver boards cost about $15 each (plus S&H).  I'll be trying to design a board that can be built for less than $30 to drive all the motors we need for the project.  The hope is to design something that can be incorporated into a kit we can call our own while being reasonable for another Hackerspace to use or even replicate from scratch.


A secondary design restraint is to make the custom board a drop-in replacement for the EasyDriver boards, so someone trying to build our CNC can use either without software changes (unbelievably, some people actually enjoy soldering custom circuitry - seems to be good for impressing upon non-tech significant others that your hobbies are challenging).
A secondary design restraint is to make the custom board a drop-in replacement for the EasyDriver boards, so someone trying to build our CNC can use either without software changes.  Unfortunately, there will be one major difference:  the Phase II driver will full-step whereas the EasyDriver micro-steps.  Hopefully this is only a minor software change, like a configuration setting.


== Phase III ==
== Phase III ==
Line 28: Line 28:
If the home grown driver is green-lighted by [[DIY CNC Router]] team, build soldered board and then test driving and controlling actual project motors with an [[Arduino]] controller.
If the home grown driver is green-lighted by [[DIY CNC Router]] team, build soldered board and then test driving and controlling actual project motors with an [[Arduino]] controller.


= Code =


= Current Status - Active - Phase I =
'''[[BSMD_PhaseI_Code|Phase I]]''' (Arduino)
 
= Current Status - Active - Phase II =


'''Phase I'''
'''Phase I'''
* In progress as of Oct 7th, 2009
* Completed, demo'd Oct 20, 2009 at weekly meeting
* Completion hoped for by Oct 13th, 2009
** We discovered EasyDriver "micro-steps" motors, which ''may'' not be the greatest thing
** Arduino on order - shipment time may delay completion past the 13th
** Rough draft of software complete, just waiting for board to arrive to test


'''Phase II'''
'''Phase II'''


* R&D in progress, back-burner style
* Basic circuit planned out
* Waiting for parts


'''Phase III'''
'''Phase III'''
Line 53: Line 55:
*** Since this is just a 'make it turn' exercise, the plan is to use a potentiometer for control: the more the pot is turned left, the faster the motor turns to the left, etc.
*** Since this is just a 'make it turn' exercise, the plan is to use a potentiometer for control: the more the pot is turned left, the faster the motor turns to the left, etc.
* Also ordered some cheap $1 hall-effect sensors (four) which could possibly be of use to the [[DIY CNC Router]] project at some point.
* Also ordered some cheap $1 hall-effect sensors (four) which could possibly be of use to the [[DIY CNC Router]] project at some point.
'''Oct 20, 2009'''
* Demo'd Phase I for Jim and Paul.
** The connector broke again when I went to dissconnect it from motor.  :(
* Jim and Dave have put together a 4 motor test stand - very cool
** Dave is taking lead on EasyDrivers now, so I am moving on to Phase II


= Current Issues =
= Current Issues =


* Lead end of test motor connector is soldered to the EasyDriver, so trying to connect Phase II prototype to test motor will be a problem
* Waiting on part order
** Actual motors for project have pigtail leads and not connectors
 


= Next Steps =
= Next Steps =


* Await arrival of [[Arduino]] board and test
* I have a $5 H-Bridge chip coming with an order I made for my RC car that has not been dedicated to anything; I ordered it 'just because' - too bad I only got one.  I think it is rated for 5A.  I'll get some more after doing a proof of concept.
* Demo Phase I for project group
 


= Links of Interest =
= Links of Interest =


* http://www.schmalzhaus.com/EasyDriverQuad/index.html
* http://www.schmalzhaus.com/EasyDriverQuad/index.html
[[Category:Arduino]]
[[Category:ActiveProjects]]
[[Category:Projects]]
234

edits

Navigation menu