Makelangelo #1072 Working(ish) Custom Arduino Uno+Pololu

[Anonymous]

I’ve finally got Makelangelo #1072 working. Due to having limited materials and a drive to work from scratch, I acquired some Steppers that work well but are low impedence and don’t like being driven by the Adafruit Motor Shield, As I also had a pair of DRV8825 pololu driver boards I built a custom Arduino Uno protoshield with two drivers and servo output, and altered the Makelangelo-Firmware to support it (for some reason I didn’t just buy a RAMPS board which would be easier !).

Pictures in Action
Makelangelo #1072 in progress by Paul Hurley, on Flickr

Board
Arduino Uno Pololu protoshield by Paul Hurley, on Flickr

Result
Iron Man (partial) by Paul Hurley, on Flickr

Custom Firmware https://github.com/paulhurleyuk/Makelangelo-firmware/tree/v0.0

Currently there’s issues in the code around speed(its too slow and doesn’t really implement the feed_rate properly) and physically that the servo jogs the gondola to one side when it lifts the pen, but its a start !

Paul.

[Anonymous]

I’ve noticed the sideways jog, too. The gondola could be improved by turning the servo to swing up/down instead of left/right. Try it and share your findings?

[Anonymous]

Thanks for the thought, I’ll certainly try it. I was also wondering how hard it would be to make a linkage that translates the servo into pure in/out motion via wire links, I’ll try both and report back.

Its all a bit bodged at the moment, I hope to 3d print a better pen holder once I have a better design, and possibly move from nylon string/bobbins to belt/gears, but I’m happy with the results so far !

Thanks for your contributions and ideas !

Paul.

[Author]

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