Autoleveling on 3D printers: 9 myths and 12 sensors tested!

There are many options for a 3D printer's bed sensor and even more misconceptions about what they can and should do. So after a ton of testing with a custom-built precision test apparatus (TM), 9 myths about these sensors have been examined - and we got a ton of data about how precise each one can be!
🛒 M8, 2mm inductive sensor (5V) s.click.aliexpress.com/e/UnYVZFe
🛒 M12, 4mm inductive sensor s.click.aliexpress.com/e/e6QJqn6
🛒 M16, 8mm inductive sensor s.click.aliexpress.com/e/fuVJu3F
🛒 M16, adjustable distance capacitive sensor s.click.aliexpress.com/e/YfIQFie
🛒 M16, 20mm capacitive sensor s.click.aliexpress.com/e/ujEuvZf
🛒 David Crocker's IR sensor www.escher3d.com/
🛒 SHARP analog sensor s.click.aliexpress.com/e/mEMnaQF
🛒 Microswiches s.click.aliexpress.com/e/2z3Njm2
🛒 BLTouch geni.us/BLTouch
🎥 All my video and editing gear toms3d.org/my-gear
👐
/ toms3dp
Certain elements may not be included in the CC-BY-AS license, e.g. third-party images and music. Trademarks are property of their respective owners.
Polygon background created by Starline - Freepik.com
Standard deviation graph by Jeremy Kemp under CC-BY 2.5
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👐 Enjoying the videos? Support my work on Patreon! / toms3dp

[@slimanus8m]

Its been 4 years, will be cool to see a redo with current offerings

[@MAGA_Patriot2024]

I'm officially finished with 3d/bl touches...they're both garbage, so yeah I'd like to see a 2021 sensor showdown myself 🙂

[@slimanus8m]

@@MAGA_Patriot2024 They really are garbage. for me after a long journey I came back to the source. end stop prob - klicky, the simpler the better

[@mynameisdex8785]

@@slimanus8m its been 5 years now

[@slimanus8m]

@@mynameisdex8785 Damn

[@slimanus8m]

@@mynameisdex8785 Ya....Now its official, just use Klicky or even Unklicky. it's simple cheap and accurate and cool

[@pensandcalls]

I think you did the BLTOUCH a disservice, Tom. While the other sensors perform equally well in any position, such as your horizontal position in the test fixture, the BLTOUCH is designed to work vertically. When put in the horizontal position, the sensor pin and magnet must overcome the additional friction of sliding along the bore of the guiding hole. This can lead to inconsistent measurements due to friction and grabbing. I consistently get average variation in readings around 0.015 mm

[@jesondag]

This!. The BLtouch is probably the best sensor on the market when used properly. It doesn't care what your build surface is and once your offset is determined you never have to worry about bed leveling or adjusting anything to do with the Z axis again. I routinely start a print and walk away, and expect it to come out perfect, and it does. The autoleveling is done once the bed is up to temperature, then the nozzle wipes across a brass brush, and quickly moves to the bed and starts printing. The BLTouch is an awesome bit of kit.

[@alejandroperez5368]

0.015mm is a lot of deviation

[@Backenfutter85]

This was awesome. Finally a proper comparsion between the different sensor types. Thanks a lot for your effort!

[@choschiba]

Thank you very much for this very interesting & informative video!! I love those technical contributions.

[@cdreid99999]

Wow great video thanks. This should get a lot more attention

[@brandonterry1517]

This was awesome. I love these technical kinds of videos. Thanks for the info, Tom!

[@stomping_leaf]

Incredibly thorough, concise review! Keep up the great work

[@andrewmalaty8]

How are you only at 67K subscribers? Your videos are so good and the editing lighting etc is amazing! I wish you lots of success Thomas. I really enjoy every single video that you make.

[@erhardpostinger1326]

He could get millions of subscribers from the FNL (GDR) which never learned english.

[@therealdjdemond]

Tom's videos are great and have amazing production value but how many 3D printer enthusiasts do you think are in the world? I imagine 67k people is a sizeable proportion of them.

[@andrewmalaty8]

Touché, but also lots of people that are interested in 3d printing don't have to be enthusiasts. Like you said though his production quality is probably some of the best on KZbin, and that is not an exageration. Many channels 10 hell even 100 times his size can learn a thing or two from him!

[@3DPrintingNerd]

67k is quite a small subsection of 3d printing enthusiasts. Talk to Lulzbot and Ultimaker about their sale figures. Heck, Prusa and his company are shipping 3,000 printers a month, and that's only because that is the limit at what they can produce right now, giving new orders a 7 week lead time.

[@therealdjdemond]

So this got me thinking what is the size of the global hobby 3d printing market? There's plenty of data on additive manufacturing market size but that's not people buying prusa i3 mkII's.

[@diylab]

Thank you for this comparison! We just doing the same for a customer and we were asked this question very often as we do a lot of printer customizing.

[@TheChumm]

That test machine was brilliant! I built an i3 clone following your guide and this sort of thing is really great for developing upgrades. Thanks for being so thoughtful in the design and execution of the testing.

[@gizmoguyar]

I want to address something I've been seeing floating around the internet regarding the inductive/capacitive probes. People keep saying you need a 12 V to 5V voltage divider on the output. This is partially wrong, and may, in fact, introduce more errors in your bed leveling. The sensors do absolutely need to be run from 12 volts to achieve their rated specs, but if you are careful to buy an NPN type sensor, you can simply plug the output directly into the Ramps input pin. This sensors are what is called "open collector drain" output. It means that it doesn't provide an output voltage when trigged, rather it pulls the signal provided to it to ground. The Arduino/Ramps board has internal 20 kohm pull up resistors on all of its pins (enabled in Configurations.h). This pull up provides 5 volts to the output pin of the sensor, when the sensor triggers, it pulls that 5 volt signal to ground. If you use a voltage divider, you might reduce the 5 volts enough to cause unreliable switching in the Arduino. PNP type = needs voltage divider. NPN type = do not use voltage divider.

[@MuditGupta89]

Perfect, new video right as I get home from work. Amazing content

[@inthehead1763]

Wow Tom that was a very in depth video and very well put together as usual. Thanks!

[@dvlbkrby]

Very informative video that highlights the differences in sensor types. Just what I was looking for to help decide what sensors to look at.

[@paulpardee]

This is the kind of video I subscribed for. Great content!

[@nourdraw1548]

I have not seen any video like this one, wow! super informative! keep it up man

[@spikekent]

Invaluable advice and comparisons Tom. Massive appreciation mate.

[@bobdavis7192]

What a great video. This is one of the BEST Tom. Great job!!!!!

[@hayfahvytsen]

Especially good description of what standard deviation means in this situation. Gut gemacht!

[@samuelkemp4557]

This is amazing! Finally a useful application of the scientific method to get some hard data. It is so much more convincing than people's opinions. Love your videos!

[@davidstafford4873]

So much work and planning to make this. Great job!

[@otternas3]

Guden Thomas, wie immer: Sehr Informativ und Professionell! Ich danke dir für all deine Super Videos zum Thema, diese brachten mich in die Welt des 3D-Drucks! Weiter so, alles Gute und schöne Grüße aus dem Hessen, Otter

[@you_just]

I think one of the things you have to remember is that the BLTouch is an all-in-one solution for bed leveling; it won’t interfere with your nozzle at all because of its retraction. That retraction most likely adds a significant wobble.

[@Handy-Harry]

Really great channel Tom. Keep up the good work!

[@InventorEgoSum]

Great video Tom it was really informative.

[@vagabound1010]

Incredible experimental design, helped me so much in making an informed choice. Earned my subscription and then some!

[@xThaWolfx]

This is exactly what I was looking for, thank you!

[@dariussteele3843]

I would love to see this video updated to include Ultrasonic sensors, and name brand inductance sensors like those made by Osram up to say 16mm sensing distance. That being said, this video is so helpful. Thank you for making it.

[@lasercutzinfo4718]

ultrasonic too hard to work at small distance, basically time of flight is sooooo short electronics is not fast enough to process it. if you have at least 10cm distance then there is enough time to do calculation at reasonable precision yet you need to run higher frequencies. We tried to do auto focus device at 25mm distance even there we had to give up on ultrasonic sensors.

[@manny9639]

Really cool video! The idea of applying statistics touched base, true engineering style, trial and error!

[@SimonMenu]

High quality content episode, as always ! it s a plaisure to follow you thomas

[@MacRC8D]

Your work is excellent. Thanks for the video, it's going to be very useful for my graduation project.

[@chriswalter7030]

Clear, concise, metrologically accurate and empirically awesome. Legend.

[@thomas_st]

I never thought about using such sensors for measuring the bed level. At work I use mostly inductive ones but just for checking if there is an object or not. When I saw your video about the Prusa i3MK3 and its autoleveling I had doubts about the precision, but your video here has told me better. Thank you.

[@jedijeremy]

Nicely done! Thorough as always. I learned stuff.

[@wschadow]

Well done! Great information and nice experimental set-up!

[@Surfingspider69]

Great video. I really enjoyed the scientific real world tests. More like this please

[@JessVideoDude]

Awesome video, thank you for sharing, great engineering skills too!

[@SchwettyBawls]

I know this video is over a year old at this point so I hope this is still relevant. He tested all of these sensors horizontally. The BLTouch specifically states NOT to use it that way. It needs to be hung vertically as it would be mounted on a printer. I've used a mechanical switch with manual leveling, a mechanical switch that flips up with a servo, capacitive sensors, inductive sensors, glass beds, PEI sheets, Zebra Plate from PRINTinZ, aluminum beds, and even tool steel beds. I've tried a total of 15 different sensors and 11 different beds in my few years of 3D printing. NONE of them were as accurate as simply using the BLTouch. When it is installed correctly, it just works flawlessly. Best of all it doesn't care one bit what surface you have, it will work on anything. I think it deserves a re-test.

[@pellin-unleashthebiker3101]

It has almost no deviation on his tests, maybe 3 micron, which is next to nothing. He also states that it doesn't care about the surface material. So actually even in this horizontal test it comes out as (one of) the best choices regardless of where you want to print on.

[@winandd8649]

Very, very nice testing here! Thanks Thomas! I've been using a little microswitch (with lever) on a metal strip moved by a servo. It's working flawlessly for years now. (all metal printer, no 3d printed parts) Nice to see that this turns out to be a precise way indeed :-)

[@camiloecheverry5210]

Hi, Are you still using the micro switch?

[@christopherellis5256]

Dude, you are my 3D Printing Super Hero... Love your passion for the 3D printing. I'm in the Vegas Area and they are always talking about probing, especially with Area51 so close. Lol

[@ryankrammes8245]

Very happy with David Crocker's differential IR sensor and a sheet of Printbite.

[@jasonlipavsky7371]

good video.... I like the effort you actually put into this, I really did have ever these questions

[@raise-project]

Very informative, thats exactly the content I prefere. Some more mythbusteresque explosions would be neat.

[@raise-project]

Excellent :)

[@HenryLoenwind]

Yeah, let's slam that probe through that glass with some speed! *g*

[@freelectron2029]

brillant breakdown, very rich in useful info.

[@column.01]

Thanks for your video, now I can comfortably purchase an induction sensor with the knowledge I will likely have to give up my glass bed. I appreciate all the testing you did!

[@SuperRcbuilder]

So comprehensive comparison! Thanks

[@mariomassens]

AWESOME. I don't know how you find the time, but I would to live next door to you. Thank you for your hard work!

[@TheWeekendModder]

Great Video - seriously stellar quality and effort clearly went into this. The pinned top comment is exactly the question one is left wondering. Great job!

[@haqnmaq]

+Thomas Sanladerer Great video! Aluminum tape definitely works though! I have used it multiple times, amd we also use it reliably at our Makerspace. There are different types of aluminum tape however. It looks like you are using the "metalized" type that is similar to Mylar. That stuff will not work. You need actual aluminum tape. The metalized type isn't very conductive. Actual Aluminum tape is basically just like aluminum foil with an adhesive backing. The only thing you have to watch out for is the adhesive. Alot of aluminum tape has a low temp adhesive and will start peeling up at around 50°C, but you can find some that has a high temp adhesive which is what we use under our PEI at the Maker Space.

[@haqnmaq]

You can tell by the video that it's the wrong kind of aluminum tape. Actual aluminum tape has a dull surface to it, and it is much thicker as well. Basically the tape you tested is just plastic tape with a small ammount of aluminum vapor deposited on the surface. Other than that, Great video!

[@MattBergholm]

Agreed. I have had great results with aluminum tape on glass beds!

[@Sutech118]

I've used copper tape in the past on glass, that worked pretty well as well.

[@ElectraFlarefire]

Had minor problems with some Aluminum tapes and inductive sensors due to reduced sensing distances that I didn't like quite as well, found copper tape to be far better. But either works great. In fact on my setup(8mm inductive @12v) copper has better sensing distance than the aluminum heatbed(My printer crashes on autolevel if I leave the glass off and it tries to sense the aluminum sheet) Those here who use copper/aluminium tape under 3 or 4mm glass: What is your sensing distance? I put the tape on top and just don't print in the very corners as 1mm or so above the glass is too close for me with the tape under it.

[@jhitesma]

I've been using a piece of heavy duty aluminum foil between my heated bed and glass for almost a year - with a 8mm inductive sensor it works great. It worked with a 4mm sensor as well - but was a bit too close for my tastes and Marlin's probe test seemed to show the 8mm was about the same for accuracy so I've stuck with it and been very happy.

[@3DPrintingNerd]

Is this going to be the sensor version of Fillaween? ... Sensorween?

[@professorparabellum]

你內部人員幹嘛

[@neuxstone]

Tom. You pretty much nailed this one....also you mentioned that capacitive sensors are thrown off by humidity...they are actually the instrument they use to sense humidity.

[@Ultrasonictwo]

Very good testing ... Great Job

[@improprietary1]

Ormerod represent! Seeing DC42s revised IR sensor made my day!

[@lvikng57]

When I was working on the auto-alignment at Type A Machines, I was very surprised at the unsolvable nature of the auto-alignment problem. There's essentially no way to get the desired flatness when combining the standard deviation of the sensor, with the rated flatness of aluminum, and the thermal expansion when heating to over 80C. You could conceivably do it with steel, but that has other challenges from the weight and cost of facing. Glass is really the only material we could find with below +/- 50 um flatness and dimensional stability when heated (we even managed to find some with +/- 0.3 um). Really the solution is to crowd source some magnetic glass, minimum order is 5 tons and works with induction.

[@BlackHeartScyther]

I'm game, magnetic glass ftw

[@ruyvieira104]

just epoxy glue a steel sheet to a piece of glass

[@Mr.Laidukas]

Very good video! Useful, interesting and professional. Glad I subscribed to your channel.

[@NonSleeper_Occasional_Thinker]

always enjoy your videos, also enjoying the new seinci videos, make more with those too please!! Bryan, Canada

[@Nikel87]

Good video. I have thought about switching to inductive sensor but now I just think I can keep the microswitch without the lever.

[@ntesla66]

Outstanding work!

[@harrifiedify]

This was a great summary! For once, a youtube video that has more information than I actually need :-) (btw, the links for the inductive/capacitive sensors are all pointing to the same model)

[@joetke]

pretty rigorous tests. Thanks Thomas!

[@DSchmidt54]

Thanks Thomas, you have helped me figure out why I am getting inconsistent results with my 8mm capacitive sensor. Time to go and get BL Touch instead. :/

[@surviveonadime]

another great video, thanks Tom.

[@argonaise_jay]

Wow, how informative video it is... I should applause.

[@pradiptabiswas2393]

Cool comparison. I was looking for a sensor to measure distance for my research project. So this helped me to understand the basics of the sensors. Thank you for that. Also is it possible to have the part list for your test setup? It will be really useful.

[@massimookissed1023]

I'm surprised/impressed to see how accurate the no-lever microswitch was. (And pleased to see the 6~36v 4mm sensor is good, 'cos I have one ordered :)

[@robsonleite6776]

Fantastic work, excellent video, thanks!

[@machinerin151]

Should've tested 3D touch as well, for example from the famous clone manufacturer Trianglelab.

[@LBCAndrew]

3D Touch has a deviation about 3x worse than BLTouch.

[@spinorkit]

Great info, thanks Tom. I recently installed David Crocker’s IR sensor on my Prusa i3 box frame, which uses a 3mm glass bed and a red Mk2 PCB heated bed, inked black with a permanent marker in the sensor probing areas. After watching your video, I tweaked Marlin so that G30 would output the trigger height to 3 decimal places (1 micron resolution). I turned on my printer and made 46 measurements with G30 and got an s.d. of 1.4 microns. I noticed a trend in the data, presumably due to temperature drift somewhere in the system (probably the steppers warming up my crappy M5 threaded rods so the trigger point appeared to get lower with time). So I did another 34 measurements and the s.d. was 0.8 microns, but still with an obvious trend. I think these numbers are an order of magnitude better than you got with glass. Maybe it matters what is behind the glass? I should also mention there was a thin layer of glue stick on the bed under the probing area from the last print. Also I have slightly modded my sensor board to increase the trigger height from about 2.7 mm to 3.2 mm by tweaking the angle of the outer LED using a hot-air rework station. This is so that it would clear the bulldog clips I use to hold the glass down so I could still retain my full 200x200 build area.

[@vladmirputin7139]

That's because, most likely, your bed surface is suitable for Crocker's IR sensor. The testing surfaces and setup in the video is stated as not suitable in the documentation. If you are running a glass plate on top of bare aluminum it is recommended to paint the aluminum matte black. I wish this test was done with the proper setup.

[@creamshop]

Hi Thomas, your videos are great!, thank you

[@ZTNET]

Very very informative, thank you.

[@kevin_delaney]

I liked this video a lot, I simply wish the sensor I use (David Crockers IR Sensor) had a slightly deeper/more in depth review. I am given more confidence to continue using it, however, will no longer calibrate it with the heated bed on. That is a variable I had not even thought twice of! I simply set the bed for 55° for my PolyMax PLA and calibrated it when it was done heating right before the print...Thank You for that!

[@chrisjericho7123]

I've just discovered your channel and love the friendly sound of your voice. I want to do a few small projects and I was weighing paying for prints vs buying my own printer. I found the new matter mod-t for 299 but wondered was there something better for beginners that maybe will help them as they transition to an intermediate level of skill without going a lot higher ( +$200 US) in price. In any case, I enjoy your videos. Thank you.

[@kermitsc1036]

Tom, you really should continue wit the Myth-busting line. I have been experimenting with sensors I have to say that your conclusions corroborate my experience 100%. Given mechanical switches with lever , although less precise than inductive, can be used with borosilicate glass, I will stick to those. Awesome video, congrats.

[@ryangarrison7088]

This is awesome! Also fun fact: I use an aluminum mk3 heatbed with a 3/32 inch (2.38 mm) sheet of glass AND blue tape. The 8 mm inductive sensor triggers just fine for me thankfully.

[@kuanmingchen273]

Very helpful video , thanks!

[@DudeBoerGaming]

I have a unique idea for a sensor that might work better than any of these. I know it works much better than a Microswitch for sure at least....when I built it initially I didn't know what use it may be, but now it is all quite clear! Thank you Thomas! You inspire me!

[@adamfilipowicz9260]

Thanks Thomas! very helpful

[@RJMaker]

Fantastic Tom!

[@pascalgarcia5161]

Thanks for your videos. I have experienced difficulties with sensors. After a few consecutive prints, the levelling of the bed was not accurate, but was accurate again the day after. I now make the levelling when the bed is hot, but the problem still exists. I believe that the sensor close to the bed and the head warms up little by little, and the temperature of the sensor may have some effect of the measurement.

[@nunfre88]

Inductive always!! Its like a engine position sensor :)

[@JimmyJames420]

great video! cool rig, shows the power of rapid prototyping. been thinking about Auto leveling, I have a delta that uses pressure pads, would be great to see how well it stacks up, down side is Auto leveling is tapping printer head into the bed every time.

[@antisubae]

"Alumininium" alone earned my subscription, whether it was intentional or just a typo. :D This was very informative, thanks for taking the time to do all the testing!

[@johnz5359]

The entire world uses "aluminium." Only america uses "Aluminum."

[@antisubae]

John Z Watch the video again if you didn't see what I was commenting on. I promise that no matter what country you're from, it's not generally spelled that way. Tom inserted a small item into the video that is internationally known as a "joke", and is intended to provoke a humor response in humans with at least average spelling and reading skills.

[@antisubae]

+John Z Seriously dude, look at what I wrote in my original comment, re-watch the video, and then try to be amazed at how dense you actually are. The word is intentionally misspelled both by Tom in the video, and by me above. There are extra letters in it. It doesn't say "aluminum" or "aluminium". In your efforts to claim Internet Superiority, you've completely missed the obvious.

[@dthillafap]

If the tests were conducted as in the video , what do you make of Antcap's instructions regarding how the BLTouch must be mounted ? The manufacturer's website for the BLTouch clearly states this: if the sensor is mounted horizontally it WILL give wrong results. They don't equivocate. It is a crystal clear stipulation. It is underlined even . Would you care to comment ?

[@dthillafap]

@@TraitorFelon.14.3 except it is not just an electronic device . It is an electromechanical device and it is purpose designed to work mounted vertically . My kettle is a simple electronic device , it won't work as intended if I run it on its side or upside down.

[@dthillafap]

@@TraitorFelon.14.3 i take your point . But my inquiry is more to do with the method used to derive a conclusion , rather than the merits of this or any other device evaluated in the test. Manufacturer says this device X is designed and only works when used using method Y . Testing is done using method K , results turn out to be suboptimal . Why are the results suboptimal ? In truth we don't know ,. It may well be the product is unreliable but testing by using method K is not the way to find out. Over and out.

[@chloemcholoe3280]

Yeah he should have tilted it...

[@milutzuk]

If I'd design a device like this small I'd surely factor the gravity whether I'd use a spring to push the pin out or not (as it happens I'm not a flat-earther, I "believe" in gravity). Probably the pin is pulled in by a coil (with the ferromagnetic pin acting as a core). Because it needs precision, the spring, if there is one, should be weak, but the trigger point will be more influenced by the sensor orientation. I guess you could make it switch just by shaking it in the hand. To be able to ignore the gravity direction (and to have repeatability no matter the sensor orientation), the spring should be stronger, but, in this case, the precision will go away, especially with microsteppping. Factor in the uneven friction, which can be significant for a such small device and the need to keep the price small and you'll have an answer. I don't own this small guy (BLTouch) and I didn't check the datasheet, but your observation is perfectly valid. And the BLTouch test is not valid.

[@TheAkashicTraveller]

Also the other mechanical sensor results aren't valid either because he's just testing the switch itself when to actually use it you'd need a mechanism to remove it to actually print.

[@cncmachinery3470]

You measured mostly repeatability, and mostly ignored system accuracy due to heating/cooling. Excellent video, great charts. Should have had an external digital DTI measure the setups actual position, logging, and dwelled (paused) after contact on the probe. Then the DTI log would show where the moving piece actually was at probe contact, vs the start position when all was cold. Likewise, the triggering circuit for probe hit is critical. I did a lot of work on this, 8 years ago, on testing for lathe spindle index sensors, and we proved conclusively that sensors will give very fuzzy signals, that vary with temp/speed/luck. A sharp triggering circuit, and a sensor tuned to give a crisp response, will be about 100x more accurate on a range of speeds vs a typical probe "hit". I also saw that optical sensors will repeat to about 2 microns, with very simple basic cheap sensors.

[@Adikimenakis]

Excellent review and presentation Tom!! Very well done! I have a 6-7 mm glass on top of an aluminum bed. Which sensor should i use?

[@mikeschubert4890]

Super Übersicht. Danke! Ich weiss jetzt, warum mein kapazitiver Sensor so eine Streuung hatte. Benutze zur Zeit den PiBot Sensor, der auf optischer Reflektion wie der Sharp basiert. Bisher mit sehr gutem Erfolg.

[@keytree69]

Another one to try is the piezo force sensor. Mount it in your bed support or (as I did) in your hot-end mount on the carriage and it registers contact of the nozzle to the bed. Zero probe offsets in X, Y and Z, change nozzle and all you have to do is run the auto-level. Super convenient. Precision Piezo do a good rig.

[@AthanCondax]

EXCELLENT VIDEO!!!

[@geertbosch2778]

I feel like I've been in a time capsule. I got an early MakerBot CNC (#180) in 2009-ish, and was printing 3mm ABS on a raft on Kapton tape, using a .37mm layer height and no fans or heated beds. I woke up in 2021 receiving a Prusa Mini+ that prints directly on a magnetically attached and heated bed, using 50 micron layer height if I so desire, and supporting PLA, PETG and a plethora of other materials out of the box. In the old times, I tried using an optical mouse sensor for auto-leveling using focus. It actually worked with the sensor 1 mm from the bed, but I wanted something more like 10mm from the bed and never got the optics to work correctly. The idea was that the optical mouse sensor not only sensed the height, but also could read markings on the bed, or a printed sheet attached to it both for calibration precision and for communicating what to print. I never got to finish this project, but it seems like it still might be worth while: the inductive SuperPINDA doesn't even provide much headroom. Does anybody here have experience using optical focusing for Z height calibration?

[@Ryukachoo]

one thing you're missing are FSRs, force sensing resistors. i use them on my delta which has a glass bed over an aluminum heat spreader. they seem to be very repeatable but only above 0.13mm deviation, any less than that and smoothieware's autocalibration gets upset

[@jamessnell5131]

I too use FSR's with Smoothie on my delta. I like them a lot, though they have their own drawbacks too.

[@mexussound]

I have Omkon SN04-N inductive sensor. I use glass bed and have one layer of aluminum tape ON TOP of the glass where the sensor probes. It works pretty well :)

[@kevincrossland1898]

Perfect timing Thomas!!! I've been looking into upgrading my whole X carraige on my cheap I3 clone, with a new E3D V6 and titan. I was planning to use an inductive sensor with foil tape, I didnt even know about those optical sensors! my cheap chinese hotend and extruder are crapping out on me after a few years, I think i probably deformed the teflon liner trying to print either PET or nylon and there's a huge amount of internal resistance. I was printing some makergeeks PLA rated for 210-220 at 240C and only 12 mm/s, any faster or colder and the extruder skips like mad. I also dont think that it was actually 240C and my thermistor is probably going bad too

[@mkile]

Great video!

[@EngineeringVignettes]

As usual, info is very useful. Really because I am not aware of _anyone_ else who is doing these types of tests. Timely as well, as I have just started messing around with 9-point bilinear leveling using Marlin and an inductive sensor on my recently build Hypercube. - Eddy

[@a4gr]

Thanks for all that testing but now I want to know which probe is best for the Scoovo X9H. It has Kapton tape directly stuck on a glass bed with the silicon heating pad just under it. Board: RAMBo Firmware: Marlin

[@tritile]

What a great video!

[@matthiaseberhard1991]

Thanks a lot for that Video. Now all makes sense.

[@anthonymarconi3174]

Informative as always. I use a LJ12A-4-Z/BY with an LM7805 VR on the output this gives a steady 5 volt trigger signal. If you increase the input voltage does it does it strengthen the sensing distance.

[@stunamvap8617]

Very good synthesis

[@cncdaddio]

I have a question about the inductive sensors... How much 'material' do they need below and around them and at what point does it make a difference? For instance: If I trigger right on the edge of my aluminium plate it triggers lower then when probed in the middle of my plate. Does thickness play a huge role? Do they trigger higher when there is a bearing holder right below the sensing point? How thick does the aluminium need to be to not have that influence...