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Pi PICO DRO/Quill-Knee combiner

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I'm just throwing this out here in case anyone is interested.

I'm knocking-up a DRO and Knee-Quill scale combiner using a Pi PICO.

Both use the PICO's PIO (programmable input/output) to count the quadrature input from the scales . The four  PIOs unload the fast counting operations from the main program,  so enabling the rest of the code to be written in MicroPython . 

The Quill-Knee combiner reads each scale (they can be different resolutions and could even be a capacitive caliper type scale with appropriate driver) then  add or subtracts the result before pulsing a quadrature output to drive the Z input of a DRO (this can also be a different resolution) .

As a DRO, the four inputs can count any resolution , I'm setting this at 0.1um (100nm),  at upto about 12MHz  (it would take some cranking to get the knee upto that speed ;-0)

ATM I'm considering a separate  SDD1322 128x64 by 16 greyscale  display for each Axis (or may each pair) as a single large display may eat too much the PICO available RAM.
I want to implement my scrolling analogue fractional display that I used on a Visual Basic based DRO i made some years ago :

If anyone is interested, please respond and I'll post the progress here.

Very interested Bill!
As you know, I built your DRO of 15 years or more ago back then. I've still got it!

A very long time lurker,

I too would be very interested in following this and maybe if my skills alow building one.


Hi Joe , James  good to have you onboard :)

This doesn't look much ATM  but this is the heart of the DRO :

On the extreme left is a hand-wheel encoder and right , a servo motor they are  standing in for a glass scales giving a 2000 and 5000 pulse per rev quadrature output . Each feeds a PICO PIO programmed as a quadrature counter and displayed as K: ans Q: .

A third PIO input , Z: , is fed from the quadrature output pins @ 2000pulse per unit  which is currently squirting out the sum of K and Q (the slight error in the counts is due to the difference in resolutions (my mill would not see those last two digits)

Fred Bloggs:

Im just in the process of converting my 1950's German vertical mill to 3 phase with a VFD and your DRO would be a good addition, please post  :nrocks:

Best regards



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