ELFOS - a Control System for Multiple Stepper Motors


Overview


ELFOS v3 Splash Screen

Ed L. French (ELF) created an operating system to make use of stepper motors on the rose engine lathe significantly easier. This system is based on the Teensy Microcontroller and uses a Nextion Human Machine Interface touch screen.

This system was developed to

  1. Automate the mundane tasks
  2. Provide for the use of stepper motors
  3. Provide for electronically synchronizing multiple activities (much like other OT equipment is synchronized using mechanical linkages)
  4. Provide a way to do this for users who are not strongly computer-literate by using an intuitive, touch-screen interface

ELFOS versions are outlined below.

Version

Spindle

X Axis

Y Axis

B Axis

M3 Axis1

M4 Axis2

Comments

2

Version 2 has been deprecated. Upgrading to version 3 is recommended.

3

 

Notes:

  1. M3 (motor 3) is a configurable axis, and is often used for controlling the rosette phaser / multiplier
  2. M4 (motor 4) is a configurable axis, and is easily used for spherical slide

Additional pictures of this device

Examples of work produced with this device

Examples of this device in use

Usage Notes

The ELFOS V3 User Manual contains a number of calculators which make some operations easier. Examples of this include:

  • Dynamic rosette phasing with lobe multiplication
  • Using the Recip function to make a basket weave pattern

The on-line manual also includes instructions for topics like

  • Adding threads to an object

How it works

The system is comprised of these key components:


Nextion Human Machine Interface
in 3D-Printed Case

A Nextion Human Machine Interface touch screen which is the manner by which the artist interacts with the system. Ed's software includes the screen configurations for the Nextion display.

This display is often-times many feet away from the rest of the system, tethered by a single cable. Ed has developed a 3D-printed case for the 4.3" display, and the 3D printing design is on his GitHub page.


 


Teensy Microcontroller
on Printed Circuit Board

A Teensy Microcontroller is used to synchronize all the stepper motors in real time. Ed's software includes all the programming necessary for this. Ed has also developed a printed circuit board for more easily connecting all the electronics needed for the Teensy. The Teensy connects to the stepper motors via drivers.


Teensy Microcontroller

 


DM542T Stepper Driver

Each stepper motor is connected to a stepper driver. The one typically used is the StepperOnline DM542T, though there are other options.

A separate driver is needed for the spindle and for each axis.

Notes on making one

Ed has maintains the complete code base for the system on GitHub.

The documentation for building the system, along with the components required is on the MDF Rose Engine Library. The key documents are on the 2nd shelf. The two manuals of note in the Instructions for Building the Control System for Multiple Stepper Motors include:

  1. Volume 1, Part 3 which outlines how to build the system, and
  2. Volume 2 which outlines how to install the software (& upgrade it over time as new updates are released).

Recommended items are in bold.

Ver

PCB

Display Options

Micro Controller Options

Driver Options

Comments

2

4-Axis

Nextion 4.3"

Teensy 3.2
Teensy 3.5

StepperOnline DM542T1
Pololu DRV88252

Version 2 has been deprecated. Upgrading to version 3 is recommended.

3.0.5

4-Axis

Nextion 4.3"

Teensy 3.2
Teensy 3.5
Teensy 3.63

StepperOnline DM542T1 Pololu DRV88252

Other drivers can also be used, but these have been extensively tested.

5-Axis

Nextion 4.3"
Nextion 5"
Nextion 7"

Teensy 3.2
Teensy 3.5
Teensy 3.63

3.0.8

4-Axis

StepperOnline DM542T1 Pololu DRV88252

Other drivers can also be used, but these have been extensively tested.

5-Axis

Nextion 5"
Nextion 7"

Teensy 3.5
Teensy 3.63

Notes:

  1. The StepperOnline DM542T requires less re-configuration as options or connections change. However, it also requires more space than the on-board Pololu DRV8825s.
  2. The Pololu DRV8825 mounts onto the printed circuit board (PCB). However, it does require more work to ensure it is correctly setup or the chip can be overloaded, necessitating replacement.
  3. The Teensy 3.6 is faster than the 3.5; however that extra speed is really not needed. Additionally, the pins on the Teensy 3.6 are more sensitive to over voltages than the Teensy 3.5.

If you pursue making one of these, consider the 7" display options. The larger screen is much nicer to use than the 4.3" display, though it does take up more space.

More Information

Published Articles

Books and Papers

Web Sites

Presentations

Other

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About this Site

Disclaimer: eMail comments to me at OTBookOfKnowledge @ Gmail.com. The process of woodturning involves the use of tools, machinery and materials which could cause injury or be a health hazard unless proper precautions are taken, including the wearing of appropriate protective equipment.