Re: [CAD_CAM_EDM_DRO] Reflective pickup

I used an inductive pickup, made by Cherry and sold by Digikey. It
works very well. No other signal shaping electronics is required.

In order to get the 10 to 30% duty cycle necessary for TCNC to get a
proper spindle signal, the "tooth" that the pickup "sees" has to be 10
to 30% of the circumference of the perimeter. (I hope that made
sense...)

The sensor tooth must have a round face. If one uses a square tooth,
the pickup will sense the leading edge of the tooth, then turn off, then
sense the ending edge of the tooth, giving you 2 (TWO !) pulses, neither
one with enough duration to quality as a signal for TCNC.

I helps to have access to an oscilloscope when setting up the sensor.

I sent Dave K some pictures of my sensor setup. He may have posted them
in the public area of the TCNC board. I no longer have those pictures
on this computer.

Kim

On Thu, 2003-11-27 at 23:39, wanliker@... wrote:
> Can anyone on the list give me a suggested part numbet to add a pick up on a
> Sherline lathe for TurboCNC threading.
> I don't want to use a tab on the Sherline pulley due to the danger it would
> present.
> I am looking for something that can see either a reflective or a BLACK spot
> with mimimial dimensions, working distance in the range of 1/4" to 1/2" +
> range.
> I want the type that will sense off the end or side of the device, but not
> the type that has a U shape with pickup between the U sides.
> Or if you have done this to a Sherline, Please describe what you did, and
> what part/parts you used. And would you do it the same way again?
> Any suggestions would be greatly appreciated.
> Thank You,
> bill
>
> Cross posted to other groups.
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Kim Lux <lux@...>