Re: [CAD_CAM_EDM_DRO] Re: Digitizers, Renishaw

True....that's the "hole" idea (pun intended). When the light is blocked
from reaching the photocell, the circuit is interrupted, thereby indicating
a point of contact with the part...exactly the desired effect.

As long as the probe is NOT in contact with the part, the mirror would line
up properly with the photocell. Rotation of the probe about its own axis
would not deflect the light, whereas sideways or vertical movement would.
Vertical movement of the probe would cause the probe to move sideways at the
same time.

Smoke

>In the design being postulated, the idea was to have a very small pinhole
>allowing light to hit a photocell. Now, whether the pinhole is on the

raised

>edge of a disk or is fixed and the probe has a mirror on the top of it
>reflecting light towards a fixed pinhole, any rotation of the sensor stylus
>would change the alignment of the pinhole to photocell and so 'black the
>cell out' or would reflect the light away from the pinhole and so again
>prevent it from reaching the photocell.
>
>Ian
>--
>Ian W. Wright
>Sheffield UK
>www.iw63.freeserve.co.uk
>----- Original Message -----
>From: "Smoke" <Smoke@...>
>
>
>> I don't see why you'd need to keep the probe from rotating. Since the
>probe
>> is round to begin with, and all your doing is probing for vertical
>location,
>> what difference would it make?
>
>
>
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