A freeware PC-based digital readout for the home machinist
1/2/2003 : Note - The schematic and program in other sections of this site is only for the 2 axis card. If you have a 4 axis card than you need this version of the program Click Here to Download 4 axis version
Thanks to the generosity of Dan Mauch at Camtronics here are the Gerber files for the 4 axis board Click Here to Download The Gerbers
This webpage is the primary distribution site of DRO+, a software interface
for a digital readout for use with a lathe or mill, with pretentions of
becoming a CNC retrofit project. I'm writing this program to help myself
learn as much about machine tools as I can before I go out and spend the
big bucks on the actual machines. I'm a mechanical engineer by trade, so
I figure that metalwork is a hobby I can use to help my work skills, as
well as have alot of fun with.
The latest updates to the site:
The schematic required a fix to an error in the traces going from the IC's
to the power off the bus. Seems they got drawn backwards somehow!
(Tip: don't draw schematics when you're half asleep) There's
also a small change to the wiring off the LS138's and a table to help you
set the base address for the card. The hardware-enabled interface
is pretty much fully functional. There's a config file named dro.cfg
that is used to customize the interface to your needs. It has 5 lines:
For example, a typical dro.cfg file looks like this:
You can edit the dro.cfg file in any simple text editor, like Notepad or
similar (don't use a word processor like Word or Write). If you've
reached this point in the project and are having trouble, drop me an email,
I'll be happy to help you out. There's no point in waiting for me
to get these pages updated, since it's really catch-as-catch-can progress.
About the program
The current features include:
In the future, I hope to add:
SVGA or ASCII Graphics, depending on needs/taste
Multiple home references, not just one
Support for metric as well as english units
Unit conversion with user-customizable unit types
Tapping charts also expandable by user
A more detailed status report
CNC control of servo motors
Quick-CNC - Home the machine, draw a simple shape, and the machine does
A DXF file viewer
User-defined reference distance, not just zero the DRO
Pattern-following, bolt circle calculations, and scripting (the 'Human
Feeds & Speeds Calculator
Trig and Math stuff computing with graphic aids
A simple calculator with scientific functions
Anything worthwhile that you suggest!
Good news for those on smaller budgets: The text version looks
fantastic, thanks to some welcome input from Chris Braid. I ran a
quick-and-dirty version on a 386, and got a refresh rate around 20 milliseconds,
or 50 frames per second. This is way more than enough. I'd
estimate that even the lowliest 286 should get 15 FPS. Download
the text demo before you get the PC you plan on using. It's not
much, just a random number generator spitting ASCII graphics at you, but
it'll let you know exactly what the finished project will look like.
You may decide that you're happy with text and save money that might get
wasted on faster hardware.
I have a fully functional version ready to go, but I've resisted posting
it until I make sure it's tested more. I'd hate to release something
that gives bad numbers (and possibly increase the volume of metal in your
scrap buckets! ;). To test the functionality of your hardware,
you can get the PC7266 software off the US Digital website. If you
wire the board a certain way, the program runs fine, giving good test data,
except that axis 1 and 3 both respond to the X axis on the homebuilt board.
Email me if you are at a point that you need the full version, and I'll
let you have whatever is most recent on this end.
I'm trying to get more work done on the assembly instructions and tutorials,
but things get in the way, and I've let this project gather a bit too much
dust. If anyone out there has some good web references covering anything
involved here, pass 'em on and contribute to the community! I'll
post them right quick.
So, to date, we've got:
Check these links out, and get your parts ordered. I'll try to keep
chugging along on this end so that hopefully we can all have working 2-axis
DRO's before too much of spring passes by. And email me if you have
some tips for scrap dealers, good junk shops, or honest machinery dealers
in the Phoenix area. I'm still looking to fill out my shop, and I
don't know this area too well yet. Help!
The SVGA demo, with extra functions beyond the
The source code for the SVGA version, currently
in DJGPP, soon to be Borland C
The VGA demo, similar to the SVGA, but a bit
The text demo, which is just a DRO, no extended
functions added yet
The hardware grocery list page, with prices,
vendors, webpages, etc.
The schematic and assembly instructions
page, incomplete but getting there
The hardware-enabled version for those who've
got a working card
Any questions, thoughts, comments? Feel free to email at email@example.com