Tip:
Highlight text to annotate it
X
Ok folks just making a real quick video here to show you will we have
working
this is your standard uh... RAMPS
RepRap controller
uh... what i've done here it is uh... removed the
polulu drivers on this side... taken those guys out
put in a set of ten headers and made up a little connector here
with the cable running to this guy which is the
THB
sixty sixty four A H driver
we're selling the kit for this which includes the PCB board and
the parts
and the chip
uh... these drivers are really really fantastic little units it is a uh...
Toshiba made product
and it uh... will do
fifty volts and four-and-a-half amps continuous it is is not something that
uh... is a ke creating
so it's a a very good little unit we've got that hooked up to a nice big
honking
NEMA twenty-three motor here
and
over on the screen you may be able to see there in the corner prompter faces
running
printer face printer interface
and that we are stepping
in the CNC world nobody would really care about that
not a big deal you see things like that every day
what's unusual here is that
this
unit is running the Merlin firmware standard
off-the-shelf everybody's running
now with a lot of people running and it puts out he stepped pulse which is one
point eight eight
milliseconds seconds, excuse me, microseconds that's u S microseconds long u_s_ micro seconds long
very very very narrow step pulse
most
stepper motor controller
uh... systems will not the drivers will not actually handle that
so i have tried previously with uh... with the local open-source when the
Linistepper driver which
would be a great fit for the reprep community since it's open source
it just uses a PIC that you can program commonly available pretty cheap
you can build your own boards or probably even builder
uh... fa fa
a different shield that would accommodate the driver right into it the
problem is that it's running code
with in the PIC that is polling or waiting for that signal to come in and
the signal is so
short
that the PIC doesn't have time to see it and so we missteps and you get this you
know really horrible
run when you when you try to actually get to spin the motor
uh... i just you know goes crazy
so
uh... these polulu drivers uh...
the chip that they use from allegro is actually ready to being able to accept
a 1uS pulse
which is going to get very unusual most of the drivers and seen seaworld
most of these big guys like this one
um... they just cannot handle that kind of uh...
uh... tiny little pulse
this particular chip according to manufactures datasheet is actually
raided his as is meeting the minimum
uh... two point three micro second
pulse for the step als however
as you can see
it is working
perfectly
uh... even under load and this really is kind of the point here you know white
why do you care about this why are we looking at this even
well here's why
It's. I'm holding on to this pretty much as hard as I can
that hurts
uh... either the extremely strong motors
uh... and they can actually move
uh... quite quickly
i'm so i'm pretty happy with this i think this is something that
we might be able to make use of this is you know potentially useful for people
who are
um...
working with
uh... very large units very large RepRap machines
trying to expand the size of it
and that by the way it is uh... five thousand millimeters per minute
uh... on the Pronterface interface
screen right along
okay just wanted to show you that again it is exceeding manufacturers
specifications of the datasheet
uh... but this is one of the few drivers i found that he is capable of handling
those tiny little steps
uh... we are going to best meet possibility of building a little pulse
stretcher which will take that tiny one micro second pulse and stretch it out so
they could potentially be useful in a separate driver
but that is for another day thanks bye-bye