pwm and dc motor speeds

[rbisping]

I have been watching a discussion on the reprap-dev list about dc
motor speed control and it occured to me that the problem with low pwm
settings on makerbot could be eliminated by using a custom pwm output
rather than the default arduino one. The real issue with loosing
torque on the dc motor with decreasing settings is the inductive
loading and the high pwm rate of the output channel. if instead you
used a 1 sec pwm rate the motor would be driven at full voltage for
whatever 1/255th of a second and be idle the rest of the second, there
is enough spring and compression in the extrusion system its self to
allow this to equate out to a steady flow at the nozel and still
mantain reasonably precice flow rates. I realize that the push to move
to steppers is on and I am all for that but there are a lot of botters
out there that will still have dc drives for a long time in the future.