A while ago I made my own touch probe, but didn't post anything about it here.
Since this thread appeared...... http://www.cnczone.com/forums/showthread.php?threadid=28226 a few people have been asking me how I made it.

The original idea came from another website, which for some reason I can no longer find. So thanks to that guy, and if anyone has the url, please post it here.

I'm still looking for a lot of the files that I used in making the probe, but I will find them all and post them here. Every part for the probe was cut using Gcode produced by 10Bulls' CamBam.

For now here's a few pics.... I'll add more stuff as I find it and as I get time.

I hope it useful to someone.

Regards Terry...

The original idea came from another website, which for some reason I can no longer find. So thanks to that guy, and if anyone has the url, please post it here.


http://www.indoor.flyer.co.uk/probe.htm ??

There's also some info in the files section of the TurboCNC Yahoo group for a similar probe.

There was also a thread started by mikegasman:

Cheap home made Touch Probe- http://www.cnczone.com/forums/showthread.php?t=22837

Which includes the link ger posted as well...

Anyone remember those toys that used to be around, the ones that were an array of small diameter metal pins? You could push you hand into one side and the hundreds of little pins would raise to create the 3d image of your hand on the other side... You coud put any object in it, I remember watching people hold it against their face and it would make a pretty accurate profile...

Maybe someone could think of some clever way to use one of these to speed up the pointcloud scanning process... rather than have a probe scan a single point at a time, one of these arrays could be used to get thousands at once... Just a thought, maybe it'll inspire someone...

I found this in my searches for home made touch probes a while back. I still haven't made it but I almost have the thing modeled in solidworks (with sizes of ball bearings I have on hand instead of what the print shows). Aren't MM's those tasty little chocolate candies? :)

If anyone has g-code for a probe I'll gladly cut it out as I'm still a ways off from being able to generate code from my model.

I have all the gcode files for my probe, along with dxf's and CamBam files. The CamBam files will make it easier to change cutter sizes etc, as people might not have the exact cutter sizes I used.

I will be posting all these files here. I need more time to get them all together. They seem to be all over the place at the minute.

Regards Terry.

Here's the dxf, cambam and gcode for the PCB bit...

Let the probing commence! :stickpoke

Jabuffi - Spent all the afternoon while raking up leaves about the possibilities, so I'll start a new thread.
John

Ah yes... I wondered if the PCB files would appear.
Cheers 10Bulls.
I'll get the main body, upper and lower section files up later tonight.

Terry.

Here's the files for the lower half of the main body.
There are 5 files in the archive:

The main DXF file.
A CamBam file for the main pockets.
A CamBam file for the Holes.
A Gcode for the main pockets, cut with a 3mm endmill.
A Gcode for the holes, cut with a 1.5875mm endmill.

The CamBam files make it easy to change tooling parameters such as the tool size etc, then regenerate a new tool path and create the newGcode file.
Just select the machining op from the tree view on the left, type in your new cutter size, then right click the maching op and choose "Generate Tool Path". The tool path should now update using the new parameters, then right click on the machining op again to "Generate Gcode File". Easy peasy.

First run the pocketing gcode, labelled 3mm cutter. Then, leaving the part in place, run the gcode for the holes.

Regards Terry.

Thanks!

Please keep the files coming, I'm building each part as I get the file :)

Pierre

Oh crap. I forgot about this thread :withstupi . Got so much going on at the moment. Good job you posted, or it would have been an even longer wait.
I'll get right on with the next set of files.

I didn't think anyone was building it.
I'll be back......

Regards Terry.

Right. The Upper section of the main body is ready to go. Same as before.
Included in the .zip file is the.......

DXF file.
CamBam file.
And Gcode for a 3mm cutter.

Change the CamBam file to suit your requirements if needed, then regen the toolpath and Gcode. If not then just use the Gcode provided.

If anyone notices anything strange, let me know and I'll see if I can fix it. Hopefully it should run ok.

Looking forward to building your probe. Please keep the files coming. If you don’t mind, when the building is completed I will post some outputs.

MrBean

I appreciate your efforts and am looking forward to building the probe using your files. Thanks

Larry

Well, MrBean's prototype touch probe turned up (thanks very much!), so after some fun and games I finally got the thing connected and working.

I did a few modifications (he knew I would), reducing and sharpening the probe tip. I also put in a new spring rather than the piece of car wash cloth.

One of the problems with these probes is that they can stick in the open circuit state. Increasing the strength of the spring helps but this increases the probing pressure and you end up with lots of 'pin pricks' in what you are probing. I think for just digitising it may be easier to rig up some sort of microswitch and a plunger, but the other benefit of this sort of probe is that it can do edge detecting and hole scanning.

I used the Mach digitize wizard to create a point cloud. I'll need to write a new digitizing program if I plan to do much of this.

To view the results I knocked up a quick and dirty CamBam plugin which basically reads in the X,Y,Z triplets and makes a polyline out of them.
You could then take this polyline and generate an engraving mop.
To make things easier to see, you can scale the polyline by altering it's transformation matrix.
The binary and source are attached. Copy the dll into the CamBam\plugins folder.

This scan is pretty boring. It is a 10 x 2.5mm section of an Australian 10c piece (you can just see the bottom of the 10 and some lyre bird feathers). I'll post some more results soon.
The Z detail is pretty impressive. The maximum Z range is only 0.26mm.

Fantastic stuff MrBean!

Looks really nice, this is for sure a must have tool.

And now for us that still have our mouthes open and the deer in the headlights stare!!!!

When scanning (i know) a piece, could you define the area and then have it probe the piece on a .X mm grid automatically?

Thanks again Mr. Bean and 10 Bulls, For the Mr 10 Bean Probe.

Hager

Hi,

Great thread. Have to build one of these (have to finish the CNC Router first though).

Any suggestions on a probe material for use on sensitive objects that you wouldn't want damaged. By this I mean an antique made of soft wood with a varnish finish that you definitely would not want any scratches or other damage to appear on.

I would guess that a probe with a rounded, or even flat, tip could be fashioned out of some self lubrication plastic like HDPE. Or even a HDPE ball attached to the end of the metal probe may work.

It's good to see you got the probe working ok Bulls.

I'll post another file or 2 in the next few hours.

Regards Terry.

Here are the files for the lower half of the inner body. There are 4 files included.

The DXF
The CamBam file
3mm cutter Gcode
1.5875mm cutter Gcode

You could make just one Gcode file from the CamBam file and do the tool change at the appropriate point. I made 2 seperate Gcode files. I ran the 3mm cutter file first. That cuts the centre hole and the outer profile of the part.
Then I ran the 1.5875 file to cut the small pockets.

Again all the files are there so if you need to alter anything it shpuld be pretty straight forward.

Regards
Terry.

This one's for the Inner Body, Upper section.
There are 2 CamBam files for this. The first is the main pocket, which just leaves the 3 alignment studs sticking up.
The second tidies up the studs and cuts the remainder of the part.
So we have:

2 CamBam files
2 Gcode files
1 DXF

Regards Terry.

...2 CamBam files...
Ah Terry San! I see you are at one with the CamBam! Nice work! :rainfro:

I had a bit of an 'eppyfanny' whilst painting the ceiling. I wonder if you could somehow angle the pins so the inner point is lower (a bit like a shuttlecock):confused: . That would make the thing try to sit at the lowest point. I think whats happening is because the pins are
all in the same plane, there's nothing preventing it sliding side to side. I think the 'open circuit syndrome' happens when the pins slide a bit and get stuck to the balls by friction. Shinnier pins would help too. Brass and drill shafts are too rough maybe. Another idea is to have a spring on each pin pushing it down, rather than one big spring.

Scanning today didn't go too well. I got a couple of open circuits and then my Z axis started missing steps. (I'd been playing with motor tuning, trying to get more speed :( ). I noticed my 5V pull up on the parallel port pin had fallen off too. Gonna try again tomorrow.

:cheers:

That "eppyfanny" shuttlecock idea sounds like a good'un. Should be easy enough to machine a new inner body to accomodate that. Although, thinking about it, there might not be enough height inside the main body. Will have to dig out the CAD model a take a look. What kind of angle are you thinking?
45 Degrees, 20 Degrees?? Any ideas......

Have you tried a weight near the tip of the probing end? It might help a bit?

Regards Terry.

Ah Terry San! I see you are at one with the CamBam! Nice work! :rainfro:

:cheers:

CamBam is great. I'm using it more and more these days. It takes a bit of getting used to, but I can't really think of how it could be any user friendlier. By it's nature, it's not going to be the easiest thing to use ever. No CAM software is.

I hope you get back on with some more development soon. I know you're busy with other stuff, but Fingers crossed you'll pull out a bug fix or two, and maybe a couple of plugins.(nuts)

Regards Terry.

Shallow would be OK. 15-20 degree maybe?

I didn't use weight. The spring is pretty strong now so don't think it will have much effect.
I think it is pushing a bit lop-sided though. Thats why i think 3 separate springs would be better.

Any suggestions on a probe material for use on sensitive objects that you wouldn't want damaged. By this I mean an antique made of soft wood with a varnish finish that you definitely would not want any scratches or other damage to appear on.
My advice is DON'T DO IT!!!!
I'd hang on until MrBean invents a frikin laser beam (laser bean?) scanner device (flame2) :D :D
...then again

Have a question:

When using the probe is it necessary to move the probe by hand, or could you define the area and then have it probe the piece on a .X mm grid automatically?

Thanks

Have a question:

When using the probe is it necessary to move the probe by hand, or could you define the area and then have it probe the piece on a .X mm grid automatically?

Thanks

Mach3 has a couple options, one of which is a wizard that let's you specify the grid size and spacing.

Mach3 has a couple options, one of which is a wizard that let's you specify the grid size and spacing.
That's right. It's pretty basic stuff but it does the job.
It actually generates a probing program in g-code which does the scanning.
Biggest problem with it is speed (I think there may also be issues with larger numbers of data points).
Having to probe down, retract, move along a fraction of a mm then probe down again a few thousand times is slow going. Because the distances are quite small you rarely get out of the 'ramping' area of the motor speed control.
Because these probes work sideways as well, a more intelligent method would scan down then zig-zag until it hits something.
A multi-pass thing would be good to. First pass to get rough dimensions then a finer pass to digitize details. This way you can spend more time at faster feed rates.
I think it would be a nightmare to do something like this in g-code. I'd like to knock up a stand alone program to do this.

@*!?!& and $??#!@-ing %*!!?-ards!!!!

Things were going so well, then open circuits started to happen again :( .
I'm sure with a few tweaks they'll go away.

This is a 0.2mm grid scan of a dog tag. This took ~7 hours to scan.

I think I'll put probing on hold for a bit until I get more time to play with the mechanics and write some scanning software. (I've got 16 8' x 4' 18mm birch ply sheets coming in the next couple of days so I may be a little preoccupied).

I like the scanning idea.

If one could set aside enough memory for a completed scan of an object, taking into consideration the size and final resolution of the image, one might be able to speed up the scan process.

Think of it like a topographical map. It is scanned at Z height. If any peaks appear at that height, they should activate the probe and those points could be located at the correct X, Y, and Z points in memory.

On the next pass, the Z height is lowered. The probe is looking for contact. Maybe a look Ahead function could also be worked out where the system knows where the previous contact points were, and can bypass those but continue the scan at the next point.

This would allow the probe to move at some speed at a fixed point in Z axis space until contact is made. If the look ahead function works, the previously scanned areas would be bypassed and only the areas without data would be continiously probed until the scanning was complete.

Guys, I know this is complex, and I left out a lot of steps, but it might be possible if someone has a few hundred hours to spend on it.

Jerry

My advice is DON'T DO IT!!!!
I'd hang on until MrBean invents a frikin laser beam (laser bean?) scanner device (flame2) :D :D
...then again

All the commercial scanners and computer controlled measuring systems uses tools with ball tips. Shouldn't be a big problem to put a ball bearing ball at the end of the tip.

although im sure physical measuring is used for a lot of tasks, it really isnt suitable for use on antiques, as 10bulls mentioned. I have previously used laser scanners to image small statues etc, but these tend to be very expensive.

As for a 'cheap' diy solution, well if you consider a dlp projector and a decent digicam cheap, you can do pretty well with structured light scanning. Its good to sub-mm accuracy, but not as accurate as a touch probe. http://www.ercim.org/publication/Ercim_News/enw44/rocchini.html

Playing around with this has made me want to try a more sensitive probe. I was thinking of using probe tips epoxied to piezzo transducers. A gentle poke should give a good voltage spike to pick up.
...or even use a record player stylus!

I couldn't resist having one last tweak tonight. I manually bent the brass tube pins upwards and put 3 separate springs in. I put a bit of double sided carpet tape over each pin. This holds them down, stops then sliding AND gives something for the spring to stick to so it doesn't sproing out.

I also put quite long m3 screws that hold the cap down. This allows for a wide range of adjustment. Tight down results in quite a hard poking force but no doubt reliable. A couple of turns loosened I managed to get it to a point where I could reliably trigger it with my finger without drawing blood and it
didn't seem to stick. Though I don't think I'd trust it to scan any part of my anatomy any time soon.

I'm going to give it one last go tomorrow for now.

Another use for a touch probe.

Having a stiff probe may not be so bad. If you had a pointy diamond tip on the probe, you could record how far you had to push to trip the probe.
You could equate this to hardness (maybe).
At metallurgy work experience we did something similar but measured the width of the diamond imprint with a microscope).

I've often wondered how well my experiments at tempering metal work. You could use this as some sort of indicator.

It could also make a pretty effective body piercer in the wrong hands.

although im sure physical measuring is used for a lot of tasks, it really isnt suitable for use on antiques, as 10bulls mentioned. I have previously used laser scanners to image small statues etc, but these tend to be very expensive.

As for a 'cheap' diy solution, well if you consider a dlp projector and a decent digicam cheap, you can do pretty well with structured light scanning. Its good to sub-mm accuracy, but not as accurate as a touch probe. http://www.ercim.org/publication/Ercim_News/enw44/rocchini.html

I have been measuring prototypes in clay with mechanical devices. The CE-J machines are of course extremely sensitive, but if you need to leave marks on the measured device, the probe spring is too strong.

That's at least my opinion. :)

Regards,
Sven

Hi!

Can anyone help me I have problem to import DFX.cambam files (probe) from MR Bean. I have Microsoft xp service pack 2, and installed MS Net Framework1.1 and hotfix kb886903 and NET Framework 2.0 with security update. I can install Cambam and get the program to start, looks normal. And after that i downloaded files from MR Bean probcambam and try to opend it but only receive an Error message:There is an error in the MXL-document (14,55).
and a code is diffrent from file to file. I have tried the other way to install the cambam with no luck. I have two computers and thay behave in the same way, same Error. What do i do wrong please help me i really want to make the probe. And for extra info i cant load any file.

Thanks Magnus

And for extra info i cant load any file.
Bit of a stab in the dark, but it may be related to regional settings (loading DXF files will also have problems). Can you try changing your decimal character to '.' rather than ',' and see if that helps.

Eureka! I think we've cracked it!!! :banana:

The "One Penny" Touch Probe (http://www.brusselsprout.org/CNC/1P-Probe)

This probe took me a few hours to make, using pretty simple stuff and has been continuously scanning for 2 days now (90,000 cycles), without any glitches.

It's only a wobbly prototype but can resolve down to about 0.01mm.
Some surface mount bits turned up today so I'm going to build a Mk II version using a milled pcb and some other improvements MrBean and I are contemplating.

I also happen to have had dumped on me several acrylic sheets some builder was chucking out in some assorted (day glo) colours. I think that'd look pretty cool, especially a 3 LED version :rainfro:

Oh well,

enjoy!

Yeh. Forget "Intel inside", this should be badged "Electronics Outside".

well the picture isn't all that clear on your web sight.

So just to clear it up.

The coin/penny is drill thru and the bolt goes thru it?

this then rests on the pin heads for contact?

The spring pushes down on the penny/bolt for adjustment?

And the silicone is for keeping the penny from sliding around?

And from what I gather the silicone goes around the prob inside of the shaft hole underneath the pins???:stickpoke

well the picture isn't all that clear on your web sight.
Sorry, it had been drinking, I'll have words with it.

The coin/penny is drill thru and the bolt goes thru it?
Yes, so that the head is against the top (unfaced face).

this then rests on the pin heads for contact?
Yes, like a dolmen.

The spring pushes down on the penny/bolt for adjustment?
Yes

And the silicone is for keeping the penny from sliding around?
Yes. To be honest, I haven't put any on the prototype, but I thought it would be a good idea as if the probe gets pushed sideways the disk
can rub against the inside of the cylinder and hang.

And from what I gather the silicone goes around the prob inside of the shaft hole underneath the pins???:stickpoke
I would put it outside. That way you can put it on afterwards when you're happy it's working. Or you could use a small piece of silicon tube maybe.

10Bulls is it still working? Are you gonna post plans?

Mike

10 bulls - just a thought. Had you considered substituting a small cylinder of foam rubber for the spring ?
I see the spring as being asymetrical in its pressure on the penny, and the foam could also act as a seal above it. The foam could be stuck to the penny for location, and a second piece underneath the pin assembly could as as a lower dust seal.
John

10Bulls is it still working? Are you gonna post plans?
Yes, the scan completed with not one hang. The plans (such as they are) are on on the web link in post #39.

10 bulls - just a thought. Had you considered substituting a small cylinder of foam rubber for the spring ?
Yes, in fact MrBean's Mk I probe had a piece of foam for a spring.
It would certainly work and I like the idea of gluing it to the disk to help prevent sideways movement.
The design lends itself to tinkering and using what's lying around.

All the commercial scanners and computer controlled measuring systems uses tools with ball tips. Shouldn't be a big problem to put a ball bearing ball at the end of the tip.

Actually I had a brilliant idea the other night. Traditional violin makers, when they see an instrument where they want to preserve as much information as they can, make up a plaster mold cast directly from the instrument. Modern materials allow us to use a combination of silicone rubber (which will not stick to varnished surfaces) and urethane polymer to make the final casting.

A violin maker I know in NYC tells me that his sillicone/urethane castings come out so accurate that they preserve even the smallest imperfections in the surface like chipped varnish, etc.

So I make a urethane casting, then use the touch prove on that. And I can be as rough with that as I want. Couldn't be simpler.

So I make a urethane casting, then use the touch prove on that. And I can be as rough with that as I want. Couldn't be simpler.

Where do you get the casting material? Any brands you prefer?

Vince

This is my source for urethane and silicone rubber http://www.jgreer.com/ There was a paper published a couple of years ago in the journal of the violin society of america detailing the process (actually it is the transcription of a talk given by a violin maker from NYC of the method he uses. Prior to these materials it was plaster castings. I used to have a hard copy before the big hard drive crash of last summer (damn maxtor). This isn't the same paper but I found it with a quick google. http://www.abcviolins.com/moulds1.html

Oh yeah Vince. Always test on scrap wood first (john's source material sometimes changes).

intresting Topic, i get the picture, i'll start working on my own little probe..

idea!

It is possible to place this switch in the top of the Indicator and the design could be simplified.

Regards.

Se le puede colocar este interruptor en el tope del indicador y se pude simplificar el diseño.

Saludos.

Tactile Switch (tipo mouse): http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=119010

i'm not sure this will work, since it can only switch when pressed on, , and how are you gonna design a system that triggers the switch, nomatter which way you move the probe?..

anyways, to make a long story short, i've made my own probe already only 25 mm in diameter, repeatability within 0.005 mm, so i think it's accurate.. :)

http://i12.photobucket.com/albums/a220/ArieKabaalstra/Beagle-1/DSC_0473.jpg

http://i12.photobucket.com/albums/a220/ArieKabaalstra/Beagle-1/DSC_0462.jpg

idea!

It is possible to place this switch in the top of the Indicator and the design could be simplified.

Regards.

Se le puede colocar este interruptor en el tope del indicador y se pude simplificar el diseño.

Saludos.

Tactile Switch (tipo mouse): http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=119010

I ripped apart a few computer mice the other day looking to grab some parts for my new edge detector/probe. I had three Logitech mice and they all used OMRON mini-switches. I think it would be hard to adjust as there is quite a bit of hysteresis between off and on.
Looking at other parts of the mouse though the X-Y IR detection circuits are interesting. I am going to use a few of these positioned at 120 deg. and one on top of the probe shaft for Z-axis touch. With a small hole in the pcb about the size of a sewing pin it should work. Designing an adjustment method now.

Esta es mi idea

This is my idea

Saludos.

Hello Giacco,

Beautiful design.......but I see a potential problem. Your probe has no clearence for side to side movement and will only work in straight up and down probe movement. Some of the scan software has a feature that uses the side of the probe tip as much or more than it uses the end. I have a commercial probe and it has about 2mm clearence all the way around the probe shank where it comes out of the body of the probe. When using an extension for a total of 2" of shank I have quite a bit of overall movement at the tip when pressed from side to side. This allows for overtravel and helps to keep from damaging the probe while in use.

Mike

that's why i think a 3point setup is the best ( and i made my drawings just for that setup ), the slightest motion wil cause any of the 3 switches to break circuit, and thus giving the control a sign "hey!!.. something's touching!"

if you increase the diameter of the disc that operates the switch, it might even do "side probing" but i'm not sure it will be very accurate..

Es verdad, ya comprendo el funcionamiento.

It is true, already I understand the functioning.

Regards.

Second Prototype, changing concept. The sensibility might be controlled by means of the screws of adjustment. The circuit would be closed to the contact from any side. Suggestions please.
Regards.

Segundo Prototipo, cambiando concepto. La sensibilidad se podría controlar por medio de los tornillos de ajuste. El circuito se cerraría al contacto desde cualquier lado. Sugerencias por favor.
Saludos.

Giacco, I really like your engagement in the topic, but I think it's not the best solution.
The problem is that if an unexpected hit occur, the tip will be bent. The design with three pair of balls is a lot more flexible. Also it's self-aligning, the tip will be forced to fall back to same position even after a big move.
The big CMM companies also have flexible tip tools that allows several millimetres of travel.

Regards,
Sven

that's why i think a 3point setup is the best ( and i made my drawings just for that setup ), the slightest motion wil cause any of the 3 switches to break circuit, and thus giving the control a sign "hey!!.. something's touching!"

if you increase the diameter of the disc that operates the switch, it might even do "side probing" but i'm not sure it will be very accurate..
Hello Arie,
I was re-reading your post and got confused. You picture looks like a rennishaw type probe with 3 pairs of balls, but your last post said '3point setup' and disc. Can you elaborate a little please?

Also Arie, I would be interested to hear how you are getting on with your probe. You too Giacco!

...and icupeter, how is your optical system getting on?

I have a box of surface mount bits and bobs ready for my mk II probe, just need a couple of extra days in the week.

Here is a close up photo of my prototype which shows the disc resting on the pins. ideally I would have that bead of silicon around the shaft and the dayglo perspex to keep dust out and restrict the disc from wandering (the photo shows the shaft needs recentering).
The rough prototype performed well enough, I can't wait to see what a well put together one can do. I want to measure the sideways deflection distance in various direction as well...

:cheers:

with a 3-piont setup, i meant that the switches always rest on 3 sets of contacts.. just like my probe, and about any other one.. the "one switch" probe that's also posted in this thread doesn't have that setup, so it will be very hard, if not impossible to set it up right.. and have it fuctioning well..

recently i've designed a probe that's both easy to build, and accurate, it uses a disc-shaped piece of PCB, 6 copper or brass studs, and 3 steel bearing needles( or similar material, like shafts of drills )

http://i12.photobucket.com/albums/a220/ArieKabaalstra/Beagle-1/probe3.jpg

with a 3-piont setup, i meant that the switches always rest on 3 sets of contacts.. just like my probe, and about any other one.. the "one switch" probe that's also posted in this thread doesn't have that setup, so it will be very hard, if not impossible to set it up right.. and have it fuctioning well..
Ah I see, that clears things up thanks. You are obviously quite a skilled machinist and the 6 ball setup is no problem for you. Do you have any scanning results Arie?
Great work...nice drawings!

would you be willing to give up the cad files for your probe or post them hear?

maybe.. but i'll have to "tidy-up" my drawings first..i'm also thinking about selling the complete documentation, milling machine, along with all "accessories" like baby-toeclamps, T-nuts, Touchprobe, basemaster..

i don't want to sound like a dope here, but what is the funtion of the ball bearings?

thanks much

The ball bearings are contacts so there is electrical continuity through the contacts and the post when the probe is in a normal position (not touching anything). As soon as the probe tip touches something the post lifts off the ball bearings and breaks the circuit. Hope that makes sense.

it's like a lightbulb going off...got it.

Thanks for the help

John

Mr. Bean and 10 bulls have put up some great information.

My question is (this is a very old thread) is there anyone who has taken all of the information and created a probe that would be willing to share drawings, files, etc..

Has there been any advancements in the probe desing that are not noted here that would be worth incorporating??

I am looking to build a touch probe and want to build the best one I can without a lot of trial and error.

Thanks,

Kirk

My question is (this is a very old thread) is there anyone who has taken all of the information and created a probe that would be willing to share drawings, files, etc..

Has there been any advancements in the probe desing that are not noted here that would be worth incorporating??
Well this year my busy-o-meter has gone well and truly off scale, but I am finishing my 'day job' in just over a week and more touch probe development is planned. My rough as guts prototype is still working well so I will mostly be working on making it more mechanically accurate and adjustable.

ERRATA!
There is an error on the circuit diagram I posted on my web page.
R1-6 are actually 1.8kR and the R7 (from the collector of the transistor) is 12k. My apologies for this and I will try and update the web pages soon.

I recently had some fantastic feedback from someone who replicated the design using hand tools and pieces of scrap. He did a fantastic write up he plans to put on his website so I won't steal his thunder. He also alerted me to the incorrect circuit diagram (many thanks John!).

Here is a link to a guy called nophead who has turned the 1 penny touch probe upside down into a tool height adjuster for his fantastic rapid prototyping machine. He also mentions ways to possibly simplify the circuit.

http://hydraraptor.blogspot.com/2007_05_01_archive.html

Good luck captainkirk! May you boldly probe where no probe has probed before! :stickpoke

The ball bearings are contacts so there is electrical continuity through the contacts and the post when the probe is in a normal position (not touching anything). As soon as the probe tip touches something the post lifts off the ball bearings and breaks the circuit. Hope that makes sense.

Yes, the ball bearings complete the circuit, but there is a reason that they are balls. The six spheres plus the three rods form a kinematic mount that serves to precisely and repeatedly position the probe in three dimensions.

Motion in any direction will break the circuit.

Ken

i made my probe with needles from a needlebearing, and 6 copper dome-pins, tested it multiple times.

Accuracy is well within 0.002 mm, now for a second parallel port to put the thing in action.. :banana:

I like the simplicity of the mechanics in 10Bulls' probe. I am thinking of a little mod to enhance the re-centering of the probe after contact is made. Why not put a 1.25 x 45 deg chamfer/taper on the bottom of the moving disc and locate "ball head pins" of some sort to interact with the chamfer/taper? They would re-center the disc upon its return from a contact, alleviate the need to do all that drilling and positioning of multiple balls and keep the electrical simplicity/sensitivity of the original design. A diaphragm of "inner tube" type rubber sheet on the bottom of the outer body, positioned to center the moving disc and apply downward tension on it would replace the spring, keep the disc centered and seal the probe body.

the best way to make a probe recenter again is simply providing 3 resting points//

the ballbearing setup is the only way to get it right.. accuracy is far less important as it seems.. a tripod will never "wiggle", just make sure you can align the whole probe, to get the probe-needle centered.

http://i12.photobucket.com/albums/a220/ArieKabaalstra/Beagle-1/SCREENIE.jpg

Yipeee!!.. I've got mine working!!

http://www.youtube.com/watch?v=dzRdQG5nEpg

Yippeee.. Got my probe working...

Done some more work on the scanning program.. i scanned a model of a Mercedes CLK with a " profile following " routine..

first the probe moves down, until it touches, retracts and probes sideways.
if it doesn't touch within a give distance, it moves down until touching, if it touches something while going sideways, it will retract again..

saves a lot of time (nuts)

Im a newbie here ...sorry...if this was asked or answer in another post,
but what soft ware are you using... in your below post? to capture the probe
xyz? data

I was wonder how 3d articuating arm work? eg for example...in the old days
the granite shop would send someone out to from the shop to make up a template of your wall for granite counter tops... not any more the have guy with his laptop and a articulating arm / probe and they make a soft ware template..... have anyone seen this or know of a way to make a diy probe like this?

Articulated arm probes "know" their position by rotary encoders, every joint has one, and by knowing the angles of the arm sections, and their lengths, the software is able to calculate the x, y, and z coordinates

I capture my coordinates with USBCNC, a PC-based CNC controler, which is basically the only professional control for an affordable price,
www.usbcnc.com