Another Aussie Adventure in Optical Edge/Centre Finding

[Greolt]

On the Artsoft forum a member called Zarzul is making a nice anodized mount for a web cam to be used as an optical edge finder.

He is selling them together with the web cam. They look good.

http://www.artsoftcontrols.com/forum...p?topic=2519.0

Anyhow this caught my attention. This could be very handy.

I often spend quite some time accurately lining the spindle of my X3 with an edge or centre mark on a job.

Mach has a facility built in to view a video window which has cross hairs for accurately aligning with a feature.

Searching this forum there are some posts about this but not many. This suggests to me that not many people are using this feature.

Being the sort that like to have a fiddle I thought I'll have a go at this.

Though Zarzul's offering is great, me being on the other side of the world and our local dollar falling I decided it would be more sensible for me to make my own.

So off down to the local market and grabbed the most basic spec'd web cam I could find. $15

Got it home and made up a mount to suit and gave it a try.

Well it took a bit of fiddling to get it adjusted to read spot on centre but once I got that right it works like a champ.

I use the small plastic lens cap as a slip gauge to set the lens height consistently above the job, which is about 4mm.

Had to screw the lens out a fair way to get good focus this close.

The lens was a little wonky in the thread ($15 remember) so when set, I hot melt glued it. Now it is rigid.

Mach has a wizard written by German Bravo to find the centre of a hole by entering any three points.

This works really well with the camera. Edges and centre marks are easy to align.

So all up I am very pleased with this. It is a very simple to make and inexpensive.

If you have got a mill and use Mach then give it a go. Or buy one of Zarzul's

Greg

PS, the pic shows a rule with 0.5mm graduations.

[epineh]

Very interesting Greg, I am guessing you probably don't want to run the spindle while doing this

Looks like a winner !

Russell.

[Greolt]

Originally Posted by epineh ...... I am guessing you probably don't want to run the spindle while doing this ...

Ha Ha Ha I don't spose the lead would survive doing that very often.

Greg

[Oldmanandhistoy]

Hi,

Just wanted to say that is an excellent idea; thanks for sharing.

One question how did you calibrate it (align it with the spindle)?

John

[Greolt]

Originally Posted by Oldmanandhistoy Hi, Just wanted to say that is an excellent idea; thanks for sharing. One question how did you calibrate it (align it with the spindle)? John

Yeah it is a good idea. Certainly not mine though.

Firstly you need to mount it so that the lens is as close to on centre as you can.

Then if you look close, or even better look at the link to Zarzul's one, you will see it has grub screws to adjust it for precise centre.

You focus it at your chosen distance then adjust while tuning through 180 degrees till you get it perfect in each axis.

If your mount is made well it should not need recalibration very often. Very quick and easy to check anyway.

Also note that it needs to be used at a consistant height above the job.

I use the lens cap as a slip gauge between lens and job.

Greg

[Oldmanandhistoy]

More and alternative information in this thread

Webcam centre / edge / hole finder

John

[aminear]

Greg,

Thanks for the plug. I thought I would post a picture for anyone interested.

I have been using the micro innovations web camera mdl 435C , it is ideal for mounting since it has a hole in the housing directly opposite the lens and it pretty much round. The shaft has 3 adjusting screws that allow you to accurately center the camera. I have sold about 40 of these so far. If you have a lathe they are fairly easy to make, except for the recessed part, that requires a cnc or ball turning attachment, it is half round to conform to the shape of the camera.

See my attached pictures.

Zarzul aminear@wyomingwireless.com

[bill south]

Does anyone know if Art or Brian generated any information on how to use the video plug-in feature in Mach3. It appears to have many features but I'll be darn if I can figure out how to properly use them!
Bill

[Greolt]

As with most Mach stuff, documentation is a bit light on.

Brian wrote the newer video app.

I would get on to the Yahoo group and ask specific questions.

http://groups.yahoo.com/group/mach1mach2cnc/

Brian is more accessible there.

Greg