[Lston]

I just heard from Avnet and the bundle they sell in single quanities does come with the 3200cpi sensor.
http://www.cypress.com/?app=search&s...ords=CYONS1001

[kevlar129bp]

Not sure if this project has been round-filed, but I thought I would ask. Working on one myself. Just lurking for some thoughts...

Thanks for comments and thoughts,

Kevlar

[TheMeatHead]

any progress with this?

[Graham S]

Not from me at least, I lost interest, possibly because I don't need one.

If I were to build one, I'd use the avago encoders, some decent bearings and a Parallax propeller microcontroller linked to a PC via USB emulating a serial port. Then some VB or python to get x,y,z from joint angles. In many ways it is a simple project, the difficulty is making it work really well and calibrating the arm etc.

Just noticed some stuff about mouse sensors, a waste of time I think.

Graham

[D.L]

I'm building an arm less precise, its a diy pantograph arm standing 90 deg with a ball bearing tip on one side and a laser mouse on the other end. It will have an x axis slide for taking contour slice intervals, its mainly for surface work, 'streaming' splines for 3d modelling. It's only accurate to about 0.2mm, still, it gives me splines instead of mesh or point clouds which saves hours of cad work.

(i really hate mesh!)

[vicen]

Interesting thread even if old (like me). I have not read the entire thread, but think I got the gist of it, and have a question.

Instead of having to put up with the accumulated error of several circular position encoders, why not track directly, and in an absolute manner, the position of, say, the head of the stylus? Then the only additional information required to determine the position in 3D space of the tip of the stylus, would be the position of the tip with respect to the head of the stylus.

Of course I have assumed that the head of the stylus is more easily trackable directly than is the tip, or I would have suggested tracking the tip directly.

One simple way to track the head would be to locate an LED there. This is just an example, as the LED would probably not provide sufficient accuracy.

I know there are various inexpensive and accurate techniques for 3D scanning (e.g. photogrammetric techniques) that would allow determination of the 3D position of the LED (or whatever point we chose as target).

Perhaps this idea has already been explored? If so I would be interested in a pointer.

[willofgod]

I tried direct tip tracking back in the day and ran into a couple of problems. At the time the tolerance was not good, this may no longer be the case. LOS is the big show stopper. Basically any complex enough part will have line of sight occlusions even if you paper the area with cameras.

[D.L]

"Of course I have assumed that the head of the stylus is more easily trackable directly than is the tip, or I would have suggested tracking the tip directly."

I like your thinking, a mini gps system.

[willofgod]

Nice, my order of posts reversed and I managed to reply to 10 year old post in this thread... sigh.

[D.L]

Tell me about it, this website is falling apart.

[LN-JET]

Old thread yeah, but there is some good stuff in it.
Direct tracking via leds and cameras is the principle of the Metronor system.
Metronor CMM - Next Generation Portable CMMs

Lars

[rasta]

Hi; I got a old Faro , that i would like to play with it , it does not have any cables to connect to a computer, or to a power supply
also it does not come with any software . Graham S, I know that this thread is about 20 years old , but if you can share with me to the software that you developed for this project It will be very much appreciated
as most of the download links does not work
thank you
Rasta