Best Sensor for ABL

Lookiing to choose the best sensor for ABL
Running Duet
Direct Extruder

Bed is Alum + 1/4" Glass + PEI sheet

Consider.

Capacitance Proximity Sensor
Piezo Disks - [www.thingiverse.com]
[www.ultibots.com]

PiBot Optical Reflection Endstop - [www.pibot.com]
Mini Differential IR height sensing board - [miscsolutions.wordpress.com]

Not sure what i should use.. I want to avoid the Endstop switch on a servo style.

any recommendations?

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Makerparts.ca
Your Canadian source for V-Slot Extrusion, CNC and 3D Printing Parts and Accessories.
we are proud to be an official Openbuilds distributor.

I have tried DC42s mini differential height sensor and found it accurate and relaible. The only problem I have with it is that there is an additional step needed if you change your nozzle - the height difference between the sensor trigger point and the true nozzle height needs to be set if there has been any change or adjustment.

I have been doing some trials on the piezoelectric disk method - the one you cited on Thingiverse and also at [3dprint.com] and I have found that a 27mm disk is frankly awesomely sensitive. I have yet to get it working in hot blood but hope to have something in the next week.

I have not tried piezoresistive sensors (your ultibots url) but in the distant past I used these in large numbers and was never happy with them - they may have improved since the 1990s though.

Mike

I may be biased because I make the differential IR sensor, but here is my take:

- Capacitive: as you have thick glass, the capacitance being sensed would be very low in your case, making the sensor even more sensitive to changes in temperature, humidity etc. than usual.

- Piezo disks: I haven't tried them, but sounds similar to FSRs under the bed. You would need to keep them cool even when the bed is hot, because piezoelectric properties are destroyed by even modest heat. The bed of your printer will be very heavy, so I think it may take a lot of downforce from the nozzle to trigger the sensors. PEI is rated at about 200C, so you won't want to probe when the nozzle is at ABS printing temperatures. But if you probe with the nozzle cold, then if there is any filament stuck to the bottom of the nozzle, you will get an inaccurate reading.

- PiBot: like all simple reflectance optical sensors, it will be very sensitive to bed surface, also sensitive to ambient IR including bright sunlight and incandescent light (especially halogen). One of my customers upgraded his sensor from PiBot to my IR sensor a few months ago, and reported that my IR sensor solved the problems he had with PiBot.

- My differential IR sensor: works well with PEI if you prepare the PEI in accordance with the instructions I provide, i.e. spray the underside with matt black stove/barbecue paint, cure the paint in an oven (because that's what you have to do with heat-resistant paints), and only then stick it to the bed plate with heat-resistant adhesive sheet. It's also smaller and lighter than most other head-mounted sensors.

Edited 2 time(s). Last edit at 02/24/2016 03:56AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

The BLTOUCH is stupid simple, light, and easy to set up. End of story.

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Folger Tech 2020 i3 and FT-5 as well as modified JGAurora A5 with direct drive E3D/Titan. All running the BLTOUCH.
Great kits. Having fun and running the heck out of them.
Running Marlin 1.1.0 RC8 on the i3 and FT5. Custom firmware on A5.
Folger Tech Wiki board >[folgertech.wikia.com]

When tjnamtiw says that the BLTOUCH is stupid simple, light and easy to set up then that is marketing but "End of story" is unhelpful and even plain insulting.

BLTouch looks interesting.

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Makerparts.ca
Your Canadian source for V-Slot Extrusion, CNC and 3D Printing Parts and Accessories.
we are proud to be an official Openbuilds distributor.

Quote
leadinglights
When tjnamtiw says that the BLTOUCH is stupid simple, light and easy to set up then that is marketing but "End of story" is unhelpful and even plain insulting.

WHAT ARE YOU TALKING ABOUT? Maybe 'stupid simple' doesn't translate well into what ever language you speak but it means it is very easy to understand, connect and use! How can it be insulting? I do not work for the people that make BLTOUCH but I AM a satisfied customer and I just answered the question as to viable options for bed leveling.

END OF STORY means that IMHO there can't be a simpler solution for the OP's situation. I realize that you have been on here 4 years and delight in testing the most obscure solutions but apparently you don't want to consider that there are very simple, workable solutions to the problem.

I suggest you have an appointment with a psychiatrist! I AM THE ONE INSULTED!

Edited 1 time(s). Last edit at 02/24/2016 11:17AM by tjnamtiw.

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Folger Tech 2020 i3 and FT-5 as well as modified JGAurora A5 with direct drive E3D/Titan. All running the BLTOUCH.
Great kits. Having fun and running the heck out of them.
Running Marlin 1.1.0 RC8 on the i3 and FT5. Custom firmware on A5.
Folger Tech Wiki board >[folgertech.wikia.com]

Quote
makerparts
BLTouch looks interesting.

If you print on glass, it is IMHO the easiest solution. If you get one, I'd be glad to share my configuration.h file from 1.1.0 RC3 with you. I hope that's helpful and not insulting................... ?????

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Folger Tech 2020 i3 and FT-5 as well as modified JGAurora A5 with direct drive E3D/Titan. All running the BLTOUCH.
Great kits. Having fun and running the heck out of them.
Running Marlin 1.1.0 RC8 on the i3 and FT5. Custom firmware on A5.
Folger Tech Wiki board >[folgertech.wikia.com]

If you re-read what I said, I referred only to the claim that your BLTOUCH was the end of story. As I said, this is an insult to those who are working in the field to try to get better answers.

I would suggest that you take lessons in reading and attempting to comprehend what was written.

Mike

Quote
tjnamtiw

Quote
leadinglights
When tjnamtiw says that the BLTOUCH is stupid simple, light and easy to set up then that is marketing but "End of story" is unhelpful and even plain insulting.

WHAT ARE YOU TALKING ABOUT? Maybe 'stupid simple' doesn't translate well into what ever language you speak but it means it is very easy to understand, connect and use! How can it be insulting? I do not work for the people that make BLTOUCH but I AM a satisfied customer and I just answered the question as to viable options for bed leveling.

END OF STORY means that IMHO there can't be a simpler solution for the OP's situation. I realize that you have been on here 4 years and delight in testing the most obscure solutions but apparently you don't want to consider that there are very simple, workable solutions to the problem.

I suggest you have an appointment with a psychiatrist! I AM THE ONE INSULTED!

I run Duet Board.. it doesnt run marlin.
runs RepRap Firmware DC 24

will it work?

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Makerparts.ca
Your Canadian source for V-Slot Extrusion, CNC and 3D Printing Parts and Accessories.
we are proud to be an official Openbuilds distributor.

Quote
leadinglights
When tjnamtiw says that the BLTOUCH is stupid simple, light and easy to set up then that is marketing but "End of story" is unhelpful and even plain insulting.

What IS marketing is "upgraded his sensor from PiBot to my IR sensor a few months ago, and reported that my IR sensor solved the problems he had with PiBot. ...... My differential IR sensor: works well with PEI if you prepare the PEI in accordance with the instructions I provide," I don't sell BLTOUCH or in any way represent them.

Edited 1 time(s). Last edit at 02/24/2016 11:25AM by tjnamtiw.

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Folger Tech 2020 i3 and FT-5 as well as modified JGAurora A5 with direct drive E3D/Titan. All running the BLTOUCH.
Great kits. Having fun and running the heck out of them.
Running Marlin 1.1.0 RC8 on the i3 and FT5. Custom firmware on A5.
Folger Tech Wiki board >[folgertech.wikia.com]

ok guys lets chill out. and just stay on topic please

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Makerparts.ca
Your Canadian source for V-Slot Extrusion, CNC and 3D Printing Parts and Accessories.
we are proud to be an official Openbuilds distributor.

I'm out of here! I'm too old to argue semantics with egotists! Just trying to help. I learned my lesson as to see who's in the topic before lending any help. Bye.

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Folger Tech 2020 i3 and FT-5 as well as modified JGAurora A5 with direct drive E3D/Titan. All running the BLTOUCH.
Great kits. Having fun and running the heck out of them.
Running Marlin 1.1.0 RC8 on the i3 and FT5. Custom firmware on A5.
Folger Tech Wiki board >[folgertech.wikia.com]

Some people just get bent out of shape about wording. This is why giving every kid on the baseball team a trophy is a bad idea.

Anyways, I would love to see your config.h file for the BlTouch.

I just got mine and am installing it on a Folgertech 2020 I3.


Thanks!!

Ernie

I want to PUBLICLY thank tjnamtiw for sharing his config with me. The BlTouch sensor is amazing. It works flawlessly and once set up it really makes printing easy. I load some files on the SD card and while I am at work I have the wife start the printer, remove prints and start over! It was nice coming home to a finished cable chain last night!!

THANKS AGAIN tjnamtiw !!!!



Ernie

You're very welcome, Ernie! I'm glad it all worked out for you. The BLTOUCH is a great little thing that does a remarkable job. Enjoy and maybe your wife will want a printer of her own!

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Folger Tech 2020 i3 and FT-5 as well as modified JGAurora A5 with direct drive E3D/Titan. All running the BLTOUCH.
Great kits. Having fun and running the heck out of them.
Running Marlin 1.1.0 RC8 on the i3 and FT5. Custom firmware on A5.
Folger Tech Wiki board >[folgertech.wikia.com]

Is the bltouch able to retract the pin in free air, or does it have to contact the bed to put the pin away?

Yes, it has an electromagnet that pulls it up. After bed leveling, It stays up.

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Folger Tech 2020 i3 and FT-5 as well as modified JGAurora A5 with direct drive E3D/Titan. All running the BLTOUCH.
Great kits. Having fun and running the heck out of them.
Running Marlin 1.1.0 RC8 on the i3 and FT5. Custom firmware on A5.
Folger Tech Wiki board >[folgertech.wikia.com]

I have to confess that sounds really nicely done. To my mind we only need to add one thing for a bltouch style probe to meet all the requirements that have been discussed in various threads recently - a reference plate that uses either force sensors or a continuity circuit to measure the offset between the probe level and the nozzle tip. That way we can still get a real nozzle tip datum without the problems of trying to detect nozzle to bed contact across all the different print surfaces. The reference plate can be specially built for the job and wouldn't need to be very big.

May I caution would-be users of bltouch that if used with Arduino/RAMPS electronics, you are likely to burn out the 5V regulator on the Arduino unless you supply external 5V power. Please don't take this as a criticism of bltouch, it is a well-known problem of Arduino/RAMPS that it cannot support enough 5V power to drive servos, graphical LCDs etc. safely. The RAMPS board ought to include a 5V regulator to power additional devices, but it doesn't.

I see that the supplier of bltouch is attempting to protecting it with patents. Is bltouch also closed source? In the spirit of RepRap, my own differential IR sensor is not patent protected, and the schematic and firmware are open source.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Yes, as far as I can see they are keeping the bltouch proprietary and closed. Your keeping the IR sensor open is noted and appreciated.

Can you really patents a solenoid with a hall sensor attach to it ? I mean its a dead simple thing.

That crazy now the thing you can patents

need to put this into some perspective.

I think this is a device that can be patented. it has some development required to produce it.
its fairly unique

compare it to this
[www.google.com]

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Makerparts.ca
Your Canadian source for V-Slot Extrusion, CNC and 3D Printing Parts and Accessories.
we are proud to be an official Openbuilds distributor.

Makerparts is correct IMHO. You can patent almost anything BUT all 20 of those CLAIMS have to be met. If you change any one thing, then you aren't infringing on the patent.

I would guess that the BLTOUCH is a design patent because, like GroupB said, you could easily print out a holder for a hall effect sensor with a pin/magnet riding in it and then come up with a circuit to energize/deenergize an electromagnet according to the signal from the servo pins. It's really just a streamlined version of the servo operated arm with a micro-switch conglomeration.

As far as breaking the spirit of REPRAP goes, anyone can replicate the workings of the BLTOUCH. You'd just have to read the patent and change one thing in the CLAIMS section. All the other sections are really meaningless as far as the patent goes. Heck, I would imagine the stepper motors are patented. Who knows, maybe the aluminum extrusion designs are patented. [www.wikinvest.com]

One good point brought up by dc42 is that some BLTOUCH'S won't work on the 5 volts at the servo rail on the RAMPS board. Mine wouldn't and I never could find out why. The first generation drew 800 ma briefly and then idled around 10 ma., I think. The new version like I have idles at just a few ma's and somewhere in the sequence briefly draws 300 ma. I found that it was just as easy to take one of the MANY old cell phone chargers I have laying around, change out the plug, and just plug it into a spare location on the servo rail. Then when I power on the printer at the power strip, it comes on. Eventually, I'll wire up the 7805 I have and have it powered from the power supply but I'm not in a hurry. I put a DC ammeter in line with the 5 volt supply and I never see it go over 1 ma.! I haven't put a scope on it and see no reason to drag it out of the attic.

Edited 2 time(s). Last edit at 02/28/2016 01:27PM by tjnamtiw.

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Folger Tech 2020 i3 and FT-5 as well as modified JGAurora A5 with direct drive E3D/Titan. All running the BLTOUCH.
Great kits. Having fun and running the heck out of them.
Running Marlin 1.1.0 RC8 on the i3 and FT5. Custom firmware on A5.
Folger Tech Wiki board >[folgertech.wikia.com]

The current draw on the BlTouch is SO much lower than a servo I am sure it would be fine on it's own. I'll measure the current draw on it when I get home tonight. I am always all about seperating high draw 5v lines using a BEC if needed though. ;-)

Ernie

Quote
dc42
May I caution would-be users of bltouch that if used with Arduino/RAMPS electronics, you are likely to burn out the 5V regulator on the Arduino unless you supply external 5V power. Please don't take this as a criticism of bltouch, it is a well-known problem of Arduino/RAMPS that it cannot support enough 5V power to drive servos, graphical LCDs etc. safely. The RAMPS board ought to include a 5V regulator to power additional devices, but it doesn't.

I see that the supplier of bltouch is attempting to protecting it with patents. Is bltouch also closed source? In the spirit of RepRap, my own differential IR sensor is not patent protected, and the schematic and firmware are open source.

BEC >> Gotta be an RC modeler!

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Folger Tech 2020 i3 and FT-5 as well as modified JGAurora A5 with direct drive E3D/Titan. All running the BLTOUCH.
Great kits. Having fun and running the heck out of them.
Running Marlin 1.1.0 RC8 on the i3 and FT5. Custom firmware on A5.
Folger Tech Wiki board >[folgertech.wikia.com]

I am going to attempt to implement this guys setup. [www.thingiverse.com] It like the BLtouch in that it wouldn't matter what the surface is and it doesn't have some big arm coming down like the others that use a servo.

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Newbie with Folgertech 2020 i3.

Is the BLTouch available for purchase now? If so where?

The only place I could find was an indiegogo campaign, which had finished as far as I could tell.

I had high hopes of using an IR sensor, but as I put my bed with PEI surface together before anyone had tried IR + PEI, I didn't paint the bottom black. Now the reflectance is too variable, and I didn't realise that PEI was transparent to IR. A physical touch sensor seems to be the right approach anyway, instead of hoping that the PEI sheet is the same thickness everywhere. At least with a physical sensor you are calibrating against the surface you're trying to print on.

Before coming across the BLTouch, I was thinking of using something like this:
[www.thingiverse.com]

They are selling the BLtouch on eBay.

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Newbie with Folgertech 2020 i3.

Quote
nebbian
I had high hopes of using an IR sensor, but as I put my bed with PEI surface together before anyone had tried IR + PEI, I didn't paint the bottom black. Now the reflectance is too variable, and I didn't realise that PEI was transparent to IR. A physical touch sensor seems to be the right approach anyway, instead of hoping that the PEI sheet is the same thickness everywhere. At least with a physical sensor you are calibrating against the surface you're trying to print on.

No need to hope that the PEI sheet has uniform thickness. With the underside painted black, the reflection from the top of the PEI is what the sensor picks up.

What sort of printer do you have? If it's a delta, you need a sensor that has low mass and can be placed very close to the nozzle.

Btw when I was developing the IR sensor, I had a backup design using a solenoid activated probe and sensing the change in inductance to detect bed contact. So a bit like bltouch but without the Hall sensor. I sourced some suitable solenoids, but stopped work on it when I got the differential IR sensor working well, because of its smaller size and weight.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].