Anyone know how to make a spindle speed display

Thanks Earwigger
Yes please, any info you have would be much appreciated.

It took ALL day. But here it is! Works great. I had NO idea how electrically NOISY a CNC machine is but everytime I mounted the tach it quit working. I finally changed over the wires to shielded CAT 6 and grounded the shielding to the ground bus. That reduced the noise to the point of functionality. The new code is capable of at least 25,000 rpms - I don’t have anything faster apparently. It is also attached.CNC_Tachometer_FreqMeasureLib_v4.ino (3.0 KB)

SmallerTachVid.mp4 (8.8 MB)

Here are more detailed pics of the assembly:

Mount for the sensor made from HDPE (kitchen cutting board):

Mounting the sensor to my dust boot/air deflector plus a new LED downlight made from a book light to ease some of my Dewalt envy:

Painted my collet nut black and applied strip of reflective tape:

Cut ends off of a Cat 6 shielded patch cable. The shielding must be grounded on one end only.

Mounted directly to spindle with double sided tape.

Shot from underneath spindle turning, downlight on:

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So glad i found this topic! I just did my first real carve last night, ever!
I’m an Arduino fan for over a year now - I have the IR sensors & LED’s - I’ll start experimenting this week. (also getting a vacuum boot in the next week or so. This will be a VERY important addition to my X-Carve, in that I want to keep stats on bits, medium, and soon RPM.
not that i want everything, but besides RPM, wouldn’t it be great to have a “stressometer” that could indicate how hard the spindle (bit) is working in real-time?

Russ from Coral Springs, Florida, USA

If you have access to an old Macintosh that someone is throwing away - there is a set of thermal sensors inside (4 or 5 of them) that also operate on the I2C protocol and that would be a very easy addition to this. Put one on each stepper and one on your stepper driver chip or power supply. If I had purchased a larger display, I would have implemented this… just for fun - nothing really seems to get hot, except perhaps the shop vac. If you are using Mach 3, you can tap into the Serial out put on one of the pins and have it output locations and other stats to the display as well.