A homemade and computer controlled pen plotter/milling
machine based on a treadmill with stepper motors

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A homemade and computer controlled pen plotter/milling machine based on a treadmill with stepper motors

Report by Stefan Spännare September 6 2016, latest update February 25 2018.


Contents

1. Introduction
2. Summary of technical components and software
3. Computer program downloads and instructions New!
4. Some photos, printouts and videos the treadmill plotter and milling machine Updated!
6. References


1. Introduction

New! February 6 2018. Some stepper motor sterings computer programs are now available for
download below for the fast PCI-DIO024 digital I/O card and (the slow) Velleman K8055
USB I/O board.

Summer 2016 I came across a defective treadmill (Swe. promenadband) and got the idea
to make a computer controlled pen plotter of it with stepper motors. For some lucky reasons I
had the parts that were needed at home and they fitted surprisingly well to each other. Although
not originally belonging to each other. The resulting treadmill plotter turns out to be an almost
surprisingly well working technical device. Actually the mechanical setup of it was assembled
in less than a day.

I modified some of my old graphical computer programs for mathematical curves (se my old
ssdosmix.zip package for 32-bit OS) so an arbitrary milling machine or plotter can mill and
write them. For example a spiral, the Cocoon curve, a Dragon curve and Lorenz attractor.
The computer programs can be downloaded from this web page with instructions how to use
them. Perhaps I should already mention that a very fast PCI-DIO24 24-bit digital I/O board
(bought from JoR.se in Sweden) is used for the output signals from the computer programs
and desktop PC to the stepper motor drivers. The C-programs were compiled using Microsoft
Visual Studio Community 2015 (C/C++) which is very good and free for registred users.

November 2015 I made a CNC milling machine with a small coordinate table and stepper motors.
It has very high precision. Some images of this machine are shown soon below. Summer 2017
I sold these things again because the coordinate table was too small to be really useful.

The PCI-DIO24 I/O card is very good and fast but also quite expensive and a bit specialized.
There are USB 2.0 digital I/O cards available (for example Velleman K8055 and K8061) but
they are a bit too slow for these applications. An attractive approach would be to use a standard
breakout board with the parallel (or printer) port, but I am not so happy to program such a device.


2. Summary of technical components and software

Hardware for the treadmill plotter/milling machine

Software for the treadmill plotter/milling machine


3. Computer program downloads and instructions

Here are now C computer programs (with executables for Windows) for writing or milling
a spiral, a Dragon curve, a Cocoon curve or a Lorenz attractor curve. Read the readme.txt
file carefully as a whole before you start to use the programs. It is assumed that you have
a PCI-DIO024. digital I/O card in your computer. And a suitable stepper motor controlled
plotter or milling machine. Treadmills and old electronic typing machines can quite easily
be converted to plotters.

tmprog-DIO024.zip (1.06 MB, package version 1.02, latest update 2018-01-22) New!

readme-DIO024.txt (version 1.02, latest update 2018-01-22) New!

New! Here are now executables (for 32-bit Windows) for the Velleman K8055 USB I/O card.
Note, it is very slow. Only a few hundreds I/O operations per second. Your stepper motors
will run slow but it works.

tmprog-K8055.zip (0.33 MB, package version 1.02, latest update 2018-02-06) New!

readme-K8055.txt (version 1.02, latest update 2018-02-06) New!


4. Some photos, printouts and videos of the treadmill plotter and milling machine

Photos of the treadmill plotter and the electronics taken with my mobile.
Updated February 25 2018.

New! January 2018. Some scanned printouts from the treadmill plotter. Size
around 3500 x 2500 pixels. A spiral, a Dragon curve, a Cocoon curve and a
Lorenz attractor curve.

Three images of the coordinate table milling machine. The Proxxon KT 150
has a moving range of 150 mm x 150 mm. A small extra table is a holder of the
milling spindle motor. This little milling machine and the stepper motors were
sold again summer 2017. The coordinate table was too small to be really useful.



Two videos of the treadmill plotter writing a spiral and a Dragon curve of order 8. Here the
machine is still on the floor and with the high handle part not sawed of. The files are large
so perhaps you better download them to your computer desktop.

spiral1.mp4 (50 MB, about 75 seconds long)

spiral1-hd.mp4 (Full HD 154 MB, about 75 seconds long)

dragoncurve1.mp4 (148 MB, about 223 seconds long)

dragoncurve1-hd.mp4 (Full HD 455 MB, about 223 seconds long)


5. References

ELFA A nice electronics component shop in Sweden
JB CNC Everything for your CNC project in Sweden
JoR Measurement A place to buy very good I/O cards for PC and much more in Sweden
Velleman K8055 I/O board and many more soldering kits
Microsoft Visual Studio Community 2015 A very good and free programming environment with with C/C++ and many other languages
Embarcadero A place to download Borland BCC 5.5 compiler and much more


Author: Stefan Spännare
E-mail: stefan.sp@hotmail.com
Document created: 2016-09-06
Latest update: 2018-02-25