A freeware PC-based digital readout for the home machinist

updated 4-24-99


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:
A more detailed status report

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!

Any questions, thoughts, comments? Feel free to email at kulaga@mcs.net .