Author Topic: which optical reflection is that? 3D printer, auto leveling  (Read 1930 times)

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Offline legacy

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which optical reflection is that? 3D printer, auto leveling
« on: October 30, 2015, 11:09:42 PM »
they argued "auto leveling optical-reflection's sensor", I wonder what they have used  :-//
 

Offline legacy

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Re: which optical reflection is that? 3D printer, auto leveling
« Reply #1 on: October 30, 2015, 11:26:20 PM »

Based on infrared sensor with two fix holes spaced 20mm.


Sharp GP2Y0A21YK0F, IR distance sensor (10cm-80cm) -


I'd like to see the data sheet of this optical reflection sensor used to auto leveling, and its response, it's said that it's "Based on infrared sensor ", but I don't know if it's similar to my SHARP GP2Y0A21YK0F IR distance sensor  :-//

(and I guess NO, too inaccurate for the purpose of measuring micron)
 

Online Marco

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Re: which optical reflection is that? 3D printer, auto leveling
« Reply #2 on: October 30, 2015, 11:42:19 PM »
I'd say it's a TCRT5000L with bend leads.
 

Offline legacy

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Re: which optical reflection is that? 3D printer, auto leveling
« Reply #3 on: October 30, 2015, 11:58:14 PM »


Description
The TCRT5000 and TCRT5000L are reflective sensors which include an infrared emitter and phototransistor in a leaded package which blocks visible light.
The package includes two mounting clips. TCRT5000L is the long lead version.
 

Offline legacy

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Re: which optical reflection is that? 3D printer, auto leveling
« Reply #4 on: October 31, 2015, 08:52:12 AM »
I just wonder about the analog part, I mean, the gain of the Operational Amplifier you have to use to amplify the output from TCRT5000L in order to see 1┬Ám

is it possible?
 

Online Marco

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Re: which optical reflection is that? 3D printer, auto leveling
« Reply #5 on: October 31, 2015, 10:28:45 AM »
The precision which can be attained mostly depends on the consistency of the reflectivity of the bed I think.

I think one half of the LM358 is used as a transimpedance amplifier and the other as a comparator.
 

Offline legacy

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Re: which optical reflection is that? 3D printer, auto leveling
« Reply #6 on: November 03, 2015, 10:08:30 PM »
Studying the data sheet, and looking around for professional solutions, I guess they(@PiBot-kit) say bullshit, I do not believe that sensor is able to have a resolution of nor 1um neither 0.1mm (100 um), I guess it's 0.5mm of resolution in the best case.
 

Online Marco

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Re: which optical reflection is that? 3D printer, auto leveling
« Reply #7 on: November 04, 2015, 12:28:25 AM »
It's really hard to say, it sounds implausible but these sensors have a fairly wide beam and thus a fairly large surface reflecting and evening out any inhomogeneity in it. Over a long time it might not have repeatability with past measurements, but for a short term it might very well be able to very accurately match distances at different points which might be enough for this application.

As a pure end stop at constant temperature I wouldn't be surprised at all if it had micron level repeatability.
« Last Edit: November 04, 2015, 12:32:07 AM by Marco »
 


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