David's IR Sensor: Questions

dc42

@br7408 it may work against a PEI coated flex sheet, if the surface colour is uniform (or you can avoid probing at points where it isn't) and the PEI layer is thin. Worth a try. The IR sensor doesn't work well against a sheet of PEI on top of a bed plate, because the reflections from the front and back surfaces interfere and the thickness is large enough for that to matter.

Let me know how well it works. If we can find a surface that works well enough, then with a firmware change we could run it as a scanning Z probe.

dc42

PS there is another coating you can get on flexible build plates called PEX. I don't know whether this is also transparent to IR. If it isn't then it could be a good solution.

br7408

@Norder Thank you very much for that information. I will look into that plate and report back what I end up going with.

br7408

@dc42 I saw the PEX ones as well, some say they work better than the PEI.

I have the sensors on order, and I will design & draw up a new CAD mount once I get them. I currently have a PEI sheet that came with the printer, so I will do an initial test with that. Anything is better than this bltouch as it is giving crazy readings due to this bed.

Norder

@br7408
Regarding the falsified measurement results of the BLTouch due to the disturbing magnetic fields... I once posted something about this with a solution that works quite well, depending on which metal you use.
Maybe it will help you ?

Link to Thread:
https://forum.duet3d.com/topic/29491/hint-bltouch-incorrect-measurement-due-to-magnetic-print-bed?_=1682329087880

Google Translate
--- Original Text ---

Zu den verfälschten Messergebnissen des BLTouch wegen der störenden Magnetfeldern... dazu habe ich mal etwas gepostet mit einer Lösung die je nachdem welches Metall man nimmt, ganz gut funktioniert.
Vielleicht hilft es Dir weiter ?

Link zum Thread:
https://forum.duet3d.com/topic/29491/hint-bltouch-incorrect-measurement-due-to-magnetic-print-bed?_=1682329087880

droftarts

@br7408 For what it's worth, it is my understanding that the Creality CR Touch uses an optical sensor, which shouldn't be affected by magnetic beds. From https://www.creality3dofficial.com/products/creality-cr-touch :

Inside of CR Touch is a small PCB with an electro-magnetically controlled metal probe. The sensing function is via a light-triggered "Hall Effect" switch with a Normally Open design.

Electrically, it's a straight swap for a BLTouch, though it's a different size physically.

Ian

oliof

@dc42 I have a PEX sheet that I can test (even though it is partially destroyed, it should be sufficient for testing). I am also awaiting some other materials for testing soon, I will let you know how those go.

br7408

@Norder I tried that with what magnetic shielding tape available at a local store. Minimal improvement as these magnets are very strong.

br7408

@oliof said in David's IR Sensor: Questions:

@dc42 I have a PEX sheet that I can test (even though it is partially destroyed, it should be sufficient for testing). I am also awaiting some other materials for testing soon, I will let you know how those go.

That would be great. I ordered and received the buildtak nylon surface. I will try that and the textured PEI that I currently have and report back. I should receive the sensors tomorrow and I will start revising my printhead CAD design for mounting provisions.

br7408

I'm happy to report that Dave's IR sensor works great with TinyMachine's PEI plate and WhamBam's PEX plate. It is ok on textured PEI, but I believe the uneven-ness of the texture throws off the height map slightly.

dc42

@br7408 thanks for the feedback. I will build new IR sensor firmware soon to test with the scanning sensor support in RRF 3.4beta4.

oliof

@dc42 3.5b4, no? Also, how would one update the firmware in existing sensors at home?

dc42

@oliof said in David's IR Sensor: Questions:

Also, how would one update the firmware in existing sensors at home?

You would need a programming tool for AVR microcontrollers, such as a USBASP or AVRISP or an Arduino running the ISP program, plus a 6-pin pogo pin adapter such as https://www.sparkfun.com/products/11591.