Adding TouchDro Tach readout for my mill

[Rob]

Started adding a tach magnetics for a readout in TouchDro. I have the Glass/Magnetic Scale Adapter https://www.touchdro.com/resources/getting-started/glass-scale-adapter.html.

I started by drilling and taping 8 holes in the bottom of my spindle pulley. I plan to start with 4 magnetics but went ahead and added an additional 4 holes so they could be added if needed.


Yury started the post about the new adapters at just the right time as I was just starting to think about what connector to add for the magnetic pickup. With the new adapter having s video connector I decided to use that one. I do plan to add a DRO to my lathe later and when I do I will use the adapter I have for that and purchase a new one for the mill. Having the same connector will make it just a plug and play when I do change.

Forgot to get pictures and will try to add them later but here is the connector I used. https://www.amazon.com/dp/B00CQNU5TK?psc=1&ref=ppx_yo2ov_dt_b_product_details. I was able to take a 1/2-20 die and thread the outside of the connector and then drilled and taped the side of the housing and screwed the connector into it.

Here is the pickup that I used. https://www.amazon.com/dp/B0859SB83M?psc=1&ref=ppx_yo2ov_dt_b_product_details I held it below the magnetics with the mill running and I did not get any readout on the display. I held it fairly close but not as close as it would be when it gets mounted.

So here is my question for Yury or anyone else who is knowledgeable in this. Should this pickup work or do I need a different one? If this one should work I will go ahead and mount it so I can get it closer to the magnets. If not I will get the needed pickup and mount that one.

 

[markba633csi]

I believe it has to be fairly close (less than 1/4") to work, depending on the strength of the magnets
Make sure you have it connected correctly

 

[RJSakowski]

The distance will depend on the strength of the magnets and the construction of the Hall effect sensor. I made my own pickup from a Hall effect chip and used 40 5mm magnets on my intermediate pulley to provide feedback for the PWM controlled DC motor on my lathe. I have the chip about .030" away from the magnets.

The sensor that you linked states a 10mm distance for the supplied magnet but changing the magnets change the distance. I would suggest setting up a simple circuit with a battery and a multimeter to to determine the maximum distance for your magnets. Then I would halve that distance to ensure reliable triggering.

 

[Rob]

OK I found out my issue. The sensor is sensitive to polarity of the magnetics field and I had them in upside down. As RJ suggested I move it to the workbench and did some testing. The sensor would work with the magnetics in the opposite direction and not in the direction that I had. Now need to get some pan head screws to mount the magnetics with.


And as promised here are pictures of the connector mounted in the box. As you can see on the one connector I threaded it 1/2-20. It was on the small diameter for theading but it will work for what I am doing with it.


Thanks for the help.