Monday, February 01, 2010

A stepper controller for the Delta Robot

Some time ago, Nophead {Chris Palmer} suggested that I use microstepping instead of gearing to get the resolution that I need in using the herringbone rack and pinion with the Delta Robot kinematics. I had hesitated because doing so got me into the surface mount Allegro controller chips. I could have used the standard Reprap controller board except that it is incompatable with my Pic-based controller.

A happy solution presented itself yesterday. Pololu offers a breakout board equipped with an Allegro A4983 controller.



The A4983 is somewhat different than the A3977 that is standard in Reprap electronics in two ways. Foremost, the A4983 can handle a maximum current of only 2 amps instead of the A3977's 2.5. I don't find this compelling because in practice Repraps rarely require more than 1 amp in any case.

The winner for me is that the A4983 controller allows for microstepping down to 1/16 compared to the A3977's 1/8. While the A3977's microstepping is more than adequate for conventional Reprap machines I can use the extra resolution with the Delta Robot.

8 comments:

nophead said...

My name is Chris Palmer, don't know who Chris Dyson is but he probably wont appreciate being called nophead!

Forrest Higgs said...

Sorry Chris. Just chalk it up to me getting old and confused. It's fixed. No malice was intended. :-(

BodgeIt said...

Its the vacuum bed tie in both are innovative designers :-)

mfsamuel said...

love to see pictures when you have it wired up. i think a decent number of people are playing with these. combination of price and micro-stepping.

greg said...

i plan on going this route. mainly because the price. but i don't know what i will do for the extruder.

Cristian Paul said...

Pic-based controller?

Tell us more !

Software who drives it? schmatics?

Regards

Cristian Paul said...

btw http://www.pololu.com/catalog/product/1202

could save time to avoid external power regulator

Forrest Higgs said...

Cristian Paul said...
Pic-based controller?

http://www.3dreplicators.com/cgi-bin/cblog/index.php?/archives/537-Tommelise-3.0-I2C-board-finally-built.html

I write my own firmware.

"btw http://www.pololu.com/catalog/product/1202

could save time to avoid external power regulator"

The boards that I build already have voltage regulation, so I don't need to do that again. :-)