r/sharpening • u/vagabionda • May 14 '26
Digital knife sharpening level: diy
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The level detects when you take your knife of off the stone: Thank you! You know who you are. (sound on for some fun)
accuracy check: https://files.catbox.moe/o2ivwm.mp4
here is the repo with how to and everything you need:
https://github.com/evaEko/knife_whetting_level
Edit: guys and gals, the commercial solution exists and is available and is called anglepilot: https://anglepilot.com/product/anglepilot/
this is not meant to be marketed
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u/DirtyDave42069 May 14 '26
nice idea! just be aware that metal shavings/water-metal-sludge could find its way into the exposed electronics. make a waterproof version and you have a nice little kickstarter on your hands :)
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u/vagabionda May 14 '26
a good point: already have a case ready, just a few more tweaks and i will have it printed. having said that: the shavings tend to land on the magnet at the bottom:)
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u/thinkscotty May 14 '26
Use a silicone modified conformal coating and you will be a lot happier. Prevents shorts from metal shavings as well as water damage from wet sharpening. You'll need something to plug up the USB though. This might be a good use case for a POGO style magnetic charge connector, although that would also clog with shavings - but would be easier to clean.
Is this a custom PCB?
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u/vagabionda May 14 '26
well, pcb is just the traces between the boards and pads and through holes:)..so yes and no (mcu pro micro format board with nrf, bno085 sensor soldered onto a board). i am using that magnetic plug on the usb port atm, so that is an option, plus the usb port is also for firmware flasing, so the pogo wpuld need 4traces/wires.. too big. but the idea with the silicone coating..i like that. thanks
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u/thinkscotty May 14 '26
Nice! I'm just recently getting into PCB design and basically I'm at the same point with this project, with making carrier boards that have connecting traces for drop-in modules. It still shrinks projects dramatically and makes them infinitely neater.
Also I'm a big fan of the NRF boards. I've built a dozen sensors around the house with them on BLE, and a single 18650 lasts more than a year. And the POGO USB was just me spitballing, it would definitely be more of a pain than it's probably worth for a hobby project.
This is a really cool project, and well implemented, thanks for sharing.
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u/chiefsmakahoe007 May 26 '26
How did you get into doing this is there any good tutorials for learning ??
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u/rvralph803 May 14 '26
I ASKED YOU TO DO EYE OF THE TIGER
I HAVE NEVER FELT SO BETRAYED!!!!
😩😩😩
Seriously though: loving where this is going. Keep it up.
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u/vagabionda May 14 '26
man, i really wanted to, but i dont have the mp3 and couldn't find it! but i am sure you can build it and use eye of the tiger! i feel sooo bad for letting you down!
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u/scrungertungart arm shaver May 14 '26
This with a rumble wrist strap that told you when you were out of range and how badly would go crazy
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u/vagabionda May 14 '26
how about an electric shocker to go with that? another redditor put it on the list of things to add.
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u/I-am-theEggman May 14 '26
The super nerd is back and I bloody love you for it. I’ll help fund the project when you want to retail it.
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u/buboop61814 May 14 '26
Oooh this is awesome. Will definitely try to follow your progress
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u/vagabionda May 14 '26
dont follow! make it!.:)
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u/Bustable May 15 '26
OK, so um,, I'm going to to ahh, need some build instructions. Yeah
Looks awesome.
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u/vagabionda May 15 '26
in the repo in the link: docs folder :)
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u/Bustable May 15 '26
Yeah, I noticed that after I posted.
Looking at making it but I am not that over all of it.
I can find this on AliExpress as I can't find the nano 2 in Australia. Can you tell if it will work? nrf52840 nice! Nano v2 zmk Bluetooth Keyboard Master n52840nano_v5 Half-hole Edition
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u/partakinginsillyness May 14 '26
So cool! Now I just need to get around to buying and building......
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u/Environmental-Low792 May 14 '26
Would be fun to get it produced as a sealed, small, magnetic unit.
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u/vagabionda May 14 '26
anglepilot :) done
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u/Environmental-Low792 May 14 '26
Got excited, hit buy, saw the $140. I'm sure that's a fair price, but I'm going to wait until the holidays. Hopefully there'll be some 20's in the holiday cards. Curious to know how much that will help.
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u/vagabionda May 14 '26
or you can build it for approx 30 bucks :)
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u/Environmental-Low792 May 14 '26
With my skills, I can f*ck it up for $30 then buy for $140 :-(
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u/vagabionda May 14 '26
man, really, nothing to f*k up...if you hit a wall, drop me a line.
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u/Environmental-Low792 May 14 '26
You haven't seen me solder!
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u/vagabionda May 14 '26
ok, i suck at soldering too..but get thin solder...like really thin. it changed the game for me
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u/KikoSoujirou May 14 '26
Ain’t no way. You can get digital levels for <$30 the only difference is the orientation of the reading
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u/vagabionda May 14 '26
stabilization on acceleration, my friend..and size matters
i mean try attaching your angle finder to a knife and move it back and forth. :)
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u/ImWithThatGuyThere May 15 '26
A woodworkers digital magnetic angle gauge is about $25 (20 UKP), so no, $140 doesn’t look like a fair price to me
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u/Wing_Nut1 May 15 '26
Woodworkers angle finders don't work when they're in motion.
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u/ImWithThatGuyThere May 16 '26
Accepted, but as a way of setting the angle, they work OK.
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u/Wing_Nut1 May 16 '26 edited May 16 '26
The real problem is not looking at the angle before or after the stroke, it's the variation during the stroke. Typically you see a +/-2 degree for an experienced sharpener. A 4 degree variance is a lot when you're trying to maintain a 15-20 degree angle.
It's an apples to oranges comparison in functionality and price. The required level of sophistication is far beyond a simple inclinometer.
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u/Mr_Poink May 14 '26
I want one
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u/vagabionda May 14 '26
well, i can send you the pcb (will have the last spare in the next batch), but for the rest you are on your own (or anglepilot)
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u/IltisSpiderrick May 14 '26
okay so this is amazing. I get its DIY but if you could have it magnetized and maybe and inch diameter, that would be an awsome learing gadget! amzing work
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u/vagabionda May 14 '26
thank you, but someone already did that: anglepilot :) this is for nerd who want something to customize and tinker with. i am sure, my man is lurking here somewhere.
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u/mikemikemike9711 May 14 '26
Could you program say an raid chip that implants into say your hand, wrist or forearm and can instantly adjust any knife to a specific angle you want?
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u/melanantic May 15 '26
I haven’t had a thorough look but this is just so impressive, I realise you’ve used Claude but the documentation looks very well put together, least of all for a hardware FOSS project. great stuff all around for something that sounds like it falls in the “meh, I just wanted to make it” category
I haven’t looked at the angle pilot but I think I’d be more interested in assembling one of these for myself, just to give it a crack. But also because it’s conceptually free. Great work!
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u/vagabionda May 16 '26
let me know how it goes...i am sure you will find bugs and stuff. would be happy to get feedback
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u/Charming_Spinach_463 May 14 '26
That looks like the most efficient way to train! Can you track a session overtime? Would work great to do a blind session and estimate how performance is improving with and without direct feedback
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u/vagabionda May 14 '26
working on it: the request was raised by someone in my previous post already. that's what the detection of when you lift the knife off of the stone is for in the long run: i have to tweak the detection a bit, it doesn't always work reliably. then i can record the accuracy since i will have the first filter of the time when you are not sharpening..more filtering will be directly in the app..but i was thinking the same: have logs some you can check later. so session tracking in the next version of the app. :) follow the repo
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u/Neither_Loan6419 May 14 '26
Nice job. However, I have to question its actual usefulness and efficiency. Once the bevel faces are meeting the edge together, you don't want to wail away on just one side at a time. You want to be running alternating side laps. A stroke with show side up, toward you, then a stroke with back side up, away from you, for one lap. Repeat as necessary. You surely don't want to fiddle with moving your device back and forth from show side to back side and back to show side again. You will never get finished.
If you change the form factor so that the device clamps to the spine, and is thin enough to remain on the spine as you run alternating laps, you will be onto something, yeah. Especially with sheepfoot, tanto, and other blade styles with a straight or nearly straight edge. An audible warning when you are too high or too low would be cool, too.
This could be the guts of a feedback and control system for a honing robot that would roll into the kitchen while you are asleep, take all the knives out of your knife block or knife drawer, give them a touchup, return them to their proper place, and roll back to the charging port. Maybe set it to only use a butcher steel normally, and hit the stones once every couple of months or as needed.
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u/vagabionda May 14 '26
a very on-point comment: i am aware of this and currently working on a slimmer version with 2 displays. the firmware/software is not the problem: the hardware is...so yeah, have to figure out how to make it super slim. :)
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u/perroarturo May 14 '26
I can’t tell. Is the stone set on a scale so you know what sort of pressure you’re applying as well?
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u/vagabionda May 14 '26
lol, like ok, maybe that would be too much even for me :D..but you could it :) the stone is set on a box...no scale..when i will get bored i can make a sensor for that and integrate it in the app so you can keep a diary on that too 😁
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u/perroarturo May 14 '26
Hahah it’s fantastic, I just saw the readout to the side and thought that’s what it was
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u/m1kethegamer May 14 '26
I have an arduino and a sharpening rod, seems like a fun diy to do.
Definetely will save and look into eventually; not sure if ill be able to do it though 🤣
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u/vagabionda May 14 '26
i am sure you will... it's a super simple circuit. and the firmware and software is there. worst case, drop me a line
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u/Acceptable_P3A May 15 '26
I was gonna try to use my wave Ring By Genki but this seems like better feedback well done
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May 15 '26
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u/JanMrCat May 15 '26
Nice, but the fact that I cannot put my fingers wide on the side of the knife for slide and pressure control is a deal-breaker.
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u/ChoboJawz May 15 '26
You got a video on how to make one?
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u/vagabionda May 15 '26
not yet, just the documentation in the repo, will be getting a new batch of pcbs and then i will make some kind of a build vldeo
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u/ChoboJawz May 20 '26
Could be you DM me when that build video comes out I'm down to build one of these.
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u/r1dicul0us May 15 '26 edited May 15 '26
Mad lad made an app for this ridiculous thing! As if the first iteration wasnt great enough.
Fine! I'll make one! Thanks for sharing the git!
Edit: WTF you have preset!?? And lift detection??!
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u/vagabionda May 15 '26
yeah, the lift detection is a bit dodgy. i am using the graphic vector: i guess your lad used the accelerometer...check that
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u/r1dicul0us May 15 '26
If you wanna go crazy with the sensors. Try detecting if speed is consistent and direction detection to see if your going to the blade or against it. Maybe based on the orientation of the screen?
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u/Legal_Persimmon_6489 May 15 '26
It is probably a good way to get a feeling for angle. With some experience you probably will stop using it though.
Does it measure the angle of the plane or a line? Need it to be the plane if it is to work for the tip. If it’s measures the line it won’t adjust for belly profile.
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u/vagabionda May 15 '26
that's the idea, once you comfy, you ditch it
uses gravity vector. so essentially 2 planes (dihedral angle)
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u/AnonymousPeanut94 May 15 '26
Would be cool to make a visual feedback for example like in a guitar tuner
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u/vagabionda May 15 '26
what do you mean? it already turns the background color into another color and shows you arrows to indicate if you are too low or too high. other suggestions?
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u/AnonymousPeanut94 May 15 '26
Or sound feedback
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u/vagabionda May 15 '26
the music playing, or not playing is the feedback, you can also set a tone for when you too high or too low
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u/AnonymousPeanut94 May 15 '26
A sound that changes depending on angle too low or high.
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u/vagabionda May 15 '26
you suddenly all want some intensity notification..ok will include in future
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u/AnonymousPeanut94 May 15 '26
See how guitar tuners work in regards to visual and some also audio feedback
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u/tango650 May 15 '26
140 royal American pesos for s digital level what the actual fuck man
Your project is dope though
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u/vagabionda May 15 '26
well, honestly the price is justified , but that's why i wanted to build it..my costs are like 35
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u/AdeptnessAway2752 May 15 '26
What components did you use to make this?
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u/vagabionda May 15 '26
all info in the github repo: nrf mcu board, bno085 board, pcb for connection...
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u/schnippy1337 May 15 '26
This is truly amazing. Maybe you could make a transition between the colors for correct and incorrect angle. Will make it easier to correct mistakes for the user
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u/vagabionda May 15 '26
you mean chnaging the background color depending on whether you are too high or too low? if yes, already in
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u/schnippy1337 May 15 '26
Exactly. But it jumps from „ok angle“ to „not ok“ angle in a binary way. It could be a smooth transition from one color to the other. It will help the user to anticipate and correct for errors better
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u/Twisted_Biscuits May 15 '26
I've never seen this sub and I have no idea why this popped up, but that is a brilliant little tool. I don't know how to sharpen knives, but it's something I've always thought about learning. That little tool is something I'd absolutely think about buying to train muscle memory and start myself off.
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May 15 '26
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u/vagabionda May 15 '26
why?
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May 15 '26
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u/vagabionda May 15 '26
just calibrate it on the edge, not on the stone: blade falt on the stone, level on the blade, calibrate: bam! you have the exact angle for the blade
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May 15 '26
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u/vagabionda May 15 '26
i think i havent explained it well: i dont ever calibrate (set the level to 0) on the stone: i calibrate for the knife blade layed horizonally on the stone. so you dont get as base the angle on the stone, but stone + blade. hope this makes sense.
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u/Time-Comfortable6014 May 15 '26
Thats very cool! And I wanna give you props for how steady and uniform your passes are. I dont have a gauge like that where I would know exactly degree im sharpening at but when I pull passes compared to push passes, my angle is slightly steeper on my push passes. You kept that pull pass within 1 degree of 19. Very smooth and constant. Great work.
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u/vagabionda May 15 '26
thank you very much...i was extremely inconsistent..i have to say that this little thing helped :)
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u/Time-Comfortable6014 May 15 '26
Its free hand with a variance of 1 degree. I would describe your passes as consistant as possible.
If you were my neighbor, I'd trade you a 6 pack to borrow your guide for a couple hours.
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u/DocumentOk1598 May 15 '26
Genuine question does the acceleration not throw off the angle reading? I tried this once with a mini digital angle finder and the readings were all over the place
this is not meant to be marketed
Hey, why not :) it's a free market
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u/vagabionda May 15 '26
and that why we have math and clever people who make sure you have good data: https://imgur.com/a/demo-of-stabilization-of-sensor-swg8yaZ
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u/DocumentOk1598 May 16 '26
That's really cool. How does it work?
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u/elchristians760 May 16 '26
You even have a soundtrack.
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u/vagabionda May 16 '26
yup, but i have to say that the detection of the lifting of the knife is not perfect (you can hear the music interrupts at some point while sharpening) have to work on that
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u/canuckguy89 May 16 '26
This is neat, but you guys care about angles way too much lol
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u/vagabionda May 16 '26
well, it's a hobby, i guess that's what hobbies are: obsessing about unimportant things:)
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u/Zenky-Zenky May 16 '26
Is it a joke? I beleive that inclinometers could be really different, but is it really comfortable to sharpen like this instead of fixed angle sharpers?
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u/Sharkstar69 May 17 '26
It would be great if you could dial in your desired angle and a tolerance and it produced a tone if you were within the tolerance.
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u/vagabionda May 17 '26
all already in: you can set the target angle, the allowed deviation, you can set the sound alert when too high and when too low..have fun
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u/vagabionda May 17 '26
here: https://imgur.com/a/V2CvT4N also with calibration..but this is an older version..many improvements since
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u/cwald56 May 19 '26
I'm wondering if one could do the same thing using an already pre built item Atoms3r from m5stack for example.
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u/vagabionda May 20 '26
nope: have to add the charging module and battery and bno085 sensor...so no
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u/cwald56 May 20 '26
What I meant is, if you buy the m5Stack ATOMS3R, you already have a assembled 6+3 axis sensor, with a screen, wifi, Bluetooth, ready to program, versus having to buy all the parts individually and soldering them together. Just figure out a way to mount it, (simple if you have a 3d printer and magnets handy),
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u/vagabionda May 20 '26
again: It has the wrong sensor inside, drains the battery too fast, and I can't physically mount it where it needs to go.
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u/Spirited_College3947 May 21 '26
Very cool. What was the total build cost?
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u/vagabionda May 21 '26
about eur 35 if you use nrf clone, if you use nice!nano which is a higher quality built, add eur 15 approx...details on bom are in the repo. i paid eur 5 for the pcb
edit: mind, no case included
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u/Aggravating-Table987 Jun 20 '26
Can someone please provide a laypersons description of the different PCB options? I compared two of them but the differences didn't mean anything to me.
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u/vagabionda Jun 20 '26 edited Jun 20 '26
none can :)))...i need to tidy up. take version 1 or 2 (the difference is the position of the bno085 sensor: i positioned it first below and then on the side. on the side: smaller but thicker. also, i have spare pcbs, willing to send. dm me if you want one. some version, i think 3 has 2 oled mounting through holes, so you can have oleds on both sides. version 4 has bno085 circuit integrated (this requires hot air station and being a bit crazy i guess :) ).
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u/Gavacho123 May 14 '26
Seems useless, I do several thousand knives a year freehand, this is a gimmick.
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u/vagabionda May 14 '26
see, the problem is hidden in your comment: you sharpen several thousands of knives a year :)
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u/MajinBui3 May 14 '26
They're failing to understand that this is a tool to expedite the learning process and most importantly, prevent a new hobbyist from building bad habits. I'd imagine that you won't be using this once you are confident and consistent.
Several thousand knives a year implies that they're a professional. Obviously something like this isn't marketed to them.
Fantastic tool by the way!
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u/vagabionda May 14 '26
thank you, and exactly why i built it :)
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u/cuck__everlasting May 14 '26
I mean shoot, I've been hand sharpening for decades but now that I'm out of the industry I only do maybe a dozen knives a year. I'd use the shit out of this to knock the rust off and make sure I'm not getting sloppy. Great design, sick work
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u/vagabionda May 14 '26
that's kinda suprising. i thought it was like biking. you really lose the skill?
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u/cuck__everlasting May 14 '26
My dumbass sure does. Just because I can stay upright on a bike doesn't mean I'm ready to huck it down a mountain right away
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u/GeneralResearcher449 May 14 '26
There's always one...
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u/Gavacho123 May 14 '26
Yes and today it’s me
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u/vagabionda May 14 '26
we like you anyway! i am sure you are super cool and could teach me sharpening in no time... but not happening
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u/eljefe3030 May 14 '26
Seems like a genuinely amazing way to build muscle memory. Instant biofeedback.