A Software Defined Edge Finder with CNC Compatible Output

[rgsparber]

This Electronic Edge Finder uses very few electronic parts yet is rather complex. The complexity is in the software that runs inside one of the parts, an ATTiny85.

As with all of my other Edge Finders, the user simply connects one clip to anything conductive mounted in the spindle. A second clip connects to the table. When the thing mounted in the spindle touches a reference surface, a contact closure is generated that can be sensed by CNC software. In my case, I'm using Centroid's CNC12 system which has automatic touchdown. Very nice!

Repeatability has been measured to be less than +/- 0.0001 inches. The cost of the electronics is under $10.

If you are interested, please see

http://rick.sparber.org/SDEF.pdf


Your comments are welcome. All of us are smarter than any one of us.


Thanks,

Rick

[Paul Jones]

Rick,

Wow, the repeatability measured to be less than +/- 0.0001 inches is very impressive.

You have provided us with an excellent edge finder probe design and the written description and theory is outstanding. I am surprised at not seeing more articles about the capabilities of the ATTiny85 8-bit microprocessor with an 10-bit A/D converter first introduced in 2005 by Atmel founded in 1985. So cool to be able to use the Arduino in-system programmer (ISP) for an Arduino.

I think Atmel were ahead of their time but will be very useful the Internet of Things to come.

Thank you,

Paul Jones

[rgsparber]

Paul,

Paul,

Glad you enjoyed it. Hopefully this project will inspire others to take a second look at Arduinos in the shop.

I think people may overlook the ATTiny85 because it has so few I/O pins but what is inside is impressive. It was a perfect fit for this application.

I have IoT on my short list of things to learn. My Flow Monitor and Control has a local audible alarm but IoT will make it really useful.

Rick

[DIYer]

Thanks Rick! We've added your Software Defined Edge Finder to our
Measuring and Marking category, as well as to your builder page: Rick's Homemade Tools. Your receipt:

Software Defined Edge Finder by Rick Sparber

tags: electronics, edge finder

[Jon]

Congratulations rgsparber - your Software Defined Edge Finder is the Homemade Tool of the Week!

We had a very strong week for high-end builds, quite a few of which received more Thanks votes (a strong indicator we use for granting this prize) than rgsparber's build.

This edge finder stood out because it was an extreme lowbuck (under $10), incredibly detailed (55 pages) tool that built on multiple similar builds that were created over years, and documented in hundreds of pages.

Literally: 6 similar builds, over 6 years, comprising 262 total pages of published work, all on the subject of electronic edge finders. There's enough here for a technical reference manual or a dissertation.

Some good picks from this week:

Squareness Comparator by rossbotics
Sine Plate by olderdan
Router Table by Bellevue Woodshop
Fly Cutter by Canobi
Tap by Cascao
Pipe End Forming Tool by Frank S
Variable Speed Belt Sander by Rorschach
Tiny Thread Checker by mklotz
Lathe Tailstock Handle by Paul Jones
Tool Post Grinder by athomp
Grinder/Belt Sander by Rorschach
Finger Plate by editor@glue-it.com
Camera Dolly by Bricoleando
Recessed Plate Forming Tool by KustomsbyKent
Spring Loaded Chuck Key by Ralphxyz


rgsparber - we've added your tool entry to our All Homemade Tool of the Week winners post. And, you'll be receiving a $25 online gift card, in your choice of Amazon, PayPal, or bitcoin. Please PM me your current email address and gift card choice and I'll get it sent over right away.

Most importantly - this is your 3rd Homemade Tool of the Week win! You join these other 3-Time Homemade Tool of the Week winners: rossbotics, mr95gst, Paul Jones, Christophe Mineau, Captainleeward, immortalx, scorch, Brendon, Frank S, mklotz, Vyacheslav.Nevolya, brianhw, LMMasterMariner, jjr2001, Tuomas, olderdan, tonyfoale.

You'll notice the 3-Time Homemade Tool of the Week award trophy graphic in your postbit beneath your avatar.




Here are all of your winning tools, followed by all 6 of your edge finder builds from over the years:

CNC Controller by Rick Sparber

tags: CNC, controller

Irrigation Flow System by Rick Sparber

tags: farm and garden, electronics

Software Defined Edge Finder by Rick Sparber

tags: electronics, edge finder

Electronic Cutter Touch-down Detector by Rick Sparber

tags: machining, lathe, edge finder

Self-Compensating Electronic Edge Finder by Rick Sparber

tags: lathe, mill, edge finder

Noise Canceling Electronic Edge Finder by Rick Sparber

tags: lathe, edge finder

Lathe Electronic Edge Finder by Rick Sparber

tags: lathe, electronics, edge finder

Electronic Edge Finder by Rick Sparber

tags: electronics, edge finder

Software Defined Edge Finder by Rick Sparber

tags: electronics, edge finder

[rossbotics]

Congratulations on your win, very simple yet functional tool

[rgsparber]

Thanks!

Rick

[tonyfoale]

A worthy winner. Well done. Like you I use Arduinos and other micros for many workshop tasks.

[rgsparber]

For the longest time I saw Arduinos as a great solution looking for a problem. I look forward to finding more uses for them. Same goes for Internet Of Things.

Rick

[tonyfoale]

For the longest time I saw Arduinos as a great solution looking for a problem. I look forward to finding more uses for them. Same goes for Internet Of Things.

Rick

I didn't take up Arduinos until a year or two back. Most of my potential use was for data acquisition on various test gear like my shock dyno, engine dyno and flow bench etc. for those I found the LabJack which I can highly recommend. Although you can buy the small Arduino clones for around $5 (must be the bargain of the century) the lowest price LabJack is around $100.
As I never need to use the LabJack (which is designed as a data acquisition system) on more than one thing at a time I have mounted it in a box and brought all the terminals out to a D32 socket. So with D32 plugs on each piece of equipment I can quickly swap it around. The Arduinos are so cheap that I use dedicated ones on whatever job.
I prefer the LabJack where it is suitable, it is dumb and all the application software resides in the connected PC, it doesn't work stand alone, although some of the newer more expensive ones can do. So to swap around I just run different software on the PC, no need to upload software as you would with an Arduino if you wanted to share it between different tasks.
For me the determination as to which to use in a particular application is based on two factors.
1. If I need it to run stand alone then it's the Arduino.
2. If I need interrupts then it's the Arduino.

One example where I wanted both features was on a valve train test rig. Where i wanted to trigger a strobe light with a small incremental delay on each engine revolution to great a slow motion effect with a regular video camera.

I have not needed to try one yet but the Pi is supposed to be like an Arduino on steroids.