Big thumbs-up for dc42's IR probe!

Over the past week or so I've been trying to sort out a Z homing height problem on my Duet-equipped CoreXY printer (now sorted by a change to gcode and, hopefully, by an additional fix with new firmware).

Yesterday, while testing the gcode changes, I realised that there was something that could have caused all sorts of pain - I illuminate my bed with a pair of LED strips that are actually vehicle daytime running lights. My printer runs off 24V so used a pair of 12V lamps, and they are much too bright to look at directly (my camera has compensated for the intensity of the lights, so they don't look as bright in these photos as they really are).



At X100 Y0 Z0 these lamps are less than 50mm from the IR probe - and the probe STILL manages to find the height correctly! I am impressed...

And, before anyone says it, I know the probe works using infrared and these LED strips hardly emit any IR, but the fact that they still work when flooded with ordinary light is remarkable.

Edited 3 time(s). Last edit at 01/15/2017 04:58AM by David J.

Had one of these ir probes sitting in my upgrades box for ages... Might be time to get it hooked up I think.

I think if you have a printing surface with even (and good) reflectivity to IR then it works very well. Definitely beats inductive and capacitive sensors. If using spray of some sort this will affect the precision in some parts of the bed.

It's pretty new but I've recently tried using a Piezo disc to create a touch based hotend sensor which has taken my delta autocalibration deviation from 0.05 (with ir sensor) to 0.013 across a 330mm bed. What's needed now is to make a small neat version of this hotend mount sensor. It's promising though as it's very sensitive and very reproducible as it is irrelevant how reflective the bed surface is as it's touch based. And unlike bltouch there's no offset in x y or z.

I think there is likely to be a collaborative effort to develop this into a universal and optimal z probe. Currently discussions on this here [forums.reprap.org] and on duetwifi forum [www.duet3d.com].

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Quote
DjDemonD
I think if you have a printing surface with even (and good) reflectivity to IR then it works very well. Definitely beats inductive and capacitive sensors. If using spray of some sort this will affect the precision in some parts of the bed.

My print bed is 3mm glass with black card underneath, with hairspray on the glass. The probe works nicely.

I'm not saying it won't work but when I had hairspray on my bed, doing delta autocalibration the results were a bit variable. Noticeably better if I cleaned the hairspray off.

Now comparing this to the Piezo sensor and I'm getting much better results. David's on board with helping us to develop the Piezo sensor, his ir board can do the signal conditioning needed.

Edited 1 time(s). Last edit at 01/15/2017 09:31AM by DjDemonD.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions