Re: [CAD_CAM_EDM_DRO] Tach Sensor

Hi Bill,

I don't think I'd try to wind a pickup coil. A Hall-effect device is
what's called for. Got any scrap 5" floppy drives? They often had
them. I recall an old thread that posted a PN# for a useable device.

Probably much easier would be to use a reflective optical pickup. Check
out what Dan does at Camtronics. The sensors are available at DigiKey
too.

Alan KM6VV


William Scalione wrote:

>
> I could use a little help with a tach sensor.
>
> I have a Red Lion Controls Cub5 Counter/Rate Indicator that I would like to
> use for a spindle tach on my Dyna-Myte mill
> http://www.redlion-controls.com/products/doc/01012.pdf
>
> The sensor trigger levels are
> Vih: 4.2V min
> Vil: .5V Max
> V Max: 28VDC
>
> Current sinking: internal 40KOhms typical pulled up to 5V
>
> Ok, I assume the Vih is the min voltage pulse required to trigger the
> counter. Red Lion sells a magnetic pickup as an option for the sensor. Could
> I simply mount 2 magnets on the spindle pulley 180 degrees apart (for
> balance) and a coil of wire wrapped around a steel shank, placed close to
> the magnets as a pickup, and if so, will that generate somewhat close to the
> voltage required to trigger this thing? Will some sort of pulse shaping be
> necessary to clean up the pulses?
>
> If I will need an amp or pulse shaper for the above, should I just use a
> photo reflective or interruptor type sensor to put out a 5V pulse to the
> counter? Is there one, that anyone knows about, that requires no external
> circuitry, just Vin and ground and outputs the required pulses? Photo
> reflective would be prefered. Price is no object as long as it's cheap.
>
> Thanks from the electronically challenged.
>
> Bill