Re: [CAD_CAM_EDM_DRO] Re: CNC Etch-A-Sketch, EggBot

Just thinking about it, an optical sensor might be of use here. Normally, an
optical cable Y connector is used for this version. Drill a tiny hole in the
end of an LED, ans insert a piece of optical cable with a drop of clear cement
on it, and let dry. Insert the other end into one of the top arms of the Y
connector, and do the same thing to the other arm with an optical sensor diode/
transistor. Attach more optical cable to the bottom arm of the Y, and use the
other end for a sensor probe. When light from the LED is reflected from
something close, a certain amount of light goes back up the cable to the sensor
transistor, and gets electronically detected, outputting a signal.

This is probably not quite accurate enough distance-wise, but a two cable
version could be. Set it up such that the LED cable points light across the
front of the tip of the sensor cable. When the sensor gets a reading you know
that the tip is right next to where you want to be, and the pen needs only N
silly millitweeters more travel to be in contact. When the signal goes away,
it's time to bring it back down before continuing. Dead simple.

Bill

On Thu Jan 3 17:21:46 2002, ballendo, <ballendo@...> wrote:

>Alan,
>
>The simple thing is to use a parallelogram (think rear
>derailler,10speed) on the "pen" axis...
>
>Hi-tech would be to sense the surface, either by contact/retract (not
>good as it marks up the egg!) or with a small "angular laser"
>distance module...
>
>Hope this helps.
>
>Ballendo
>
>> > I'm wondering if any of our CAD/CAM *EGGHEADS* can suggest ways
>to track
>> > an egg's surface?
>> >
>> > Alan KM6VV

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