How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
Hi,
I have another brand of 3d printer, but I would like to adapt this sensor for it, with the help of an arduino.
To see the sensor I'm interested in, please go to : https://www.prusaprinters.org/firmware-3-4-0-with-filament-sensor-engine-2-0-is-out/
https://www.prusaprinters.org/firmware-3-4-0-with-filament-sensor-engine-2-0-is-out/
Based on the 4 pins: 2 for power and 2 for signal, I should be able to use it if i know the protocol and the commands accepted.
If anybody knows them or knows where can i find the information about them, please let me know.
Thank you,
Sorin
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
Avoid this sensor at all costs.
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
Avoid this sensor at all costs.
Why?
Having said that, software wise, this sensor will be a challenge to incorporate into another printer. It reports motion, not presence.
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
The sensor internals are designed around sensing motion of solid reflective materials, like metals. It has no compensation for materials that are semi-opaque or translucent. It's laser is also single frequency, and insensitive to most of the color spectrum: something that looks opaque to the eye might be invisible to the laser.
Just way too many issues to solve on that topic alone. Add the complexity of determining motion based on a few samples makes it even more complex. A human doesn't move in a continuos predictable way. Our motor skills are limited and our muscles have a tendency to twitch - causing short back and forth motion the sensor will detect; the software has to know about this human 'feature' and compensate. Prusa software doesn't compensate for stutter and will often detect both load and unload signals when a person is pushing filament into the extruder: as a result, the user gets an unload immediately after loading. Call it lack of debouncing ...
Anyway - not the part for detecting FDM filament.
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
There is a reason why Prusa went away from this sensor 😉
Anyway, you can use the code/usage examples from the firmware. The beauty of open source 😀
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Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
Just give it something good to look at, like a bearing. The issue of sensor sensitivity has been solved for ages.
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
Just give it something good to look at, like a bearing. The issue of sensor sensitivity has been solved for ages.
Except the bearing doesn't solve the human factor: the stutter our hands do as we try to move the filament in or out of the extruder. The sensor response is very fast and it detects these stutters. Thus the polling technique may catch a "removal" when in fact the user is "inserting" filament.
You only need to read about all of the false detections during load and unload cycles to figure out the Prusa implementation hasn't dealt with this.
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
Can’t say I’ve ever heard of that being an issue, and looking at the code, I can’t see how that occurs.
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
Read the reports of prints stopping for no reason, and the behavior goes away when the filament sensor is disabled. And the reports of having to redo filament reloads during the autoload sequence.
The sensor reports motion, either up or down. If read happens when a person jiggles upwards, the fw assumes up - or unload. If the sensor reads down, the fw assumes the user is loading. You can test it by jiggling the filament during a load. Insert it and lift it up and down a few times. But you won't have to move it far - a fraction of a mm is enough to change the sensor direction register.
Anyway - with all of the odd midprint pauses it causes, probably due to a measurement poll too soon after a retract, makes the sensor unreliable for my uses. And I have yet to do a filament swap while the sensor is enabled that I haven't had to load at least twice. But I'm an old fart and don't have a neurosurgeon's hands.
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
Duplicate post - ignore.
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
Read the reports of prints stopping for no reason, and the behavior goes away when the filament sensor is disabled. And the reports of having to redo filament reloads during the autoload sequence.
These are standard false positives which are resolved with an indirect sensor. (Or, obviously, if you insert filament, it doesn't get to the gears, but you tell the printer that it is extruding fine anyway - which would qualify as a "jam")
The sensor reports motion, either up or down. If read happens when a person jiggles upwards, the fw assumes up - or unload. If the sensor reads down, the fw assumes the user is loading. You can test it by jiggling the filament during a load. Insert it and lift it up and down a few times. But you won't have to move it far - a fraction of a mm is enough to change the sensor direction register.
I may be mistaken, but I'm pretty sure runout/jam detection (which is what sets off the unload sequence) is entirely disabled during autoloading. The only thing faffing with the filament during autoloading should do is set off the "sensor response is poor" error. Please, post a video showing this occurring.
Anyway - with all of the odd midprint pauses it causes, probably due to a measurement poll too soon after a retract, makes the sensor unreliable for my uses. And I have yet to do a filament swap while the sensor is enabled that I haven't had to load at least twice. But I'm an old fart and don't have a neurosurgeon's hands.
Midprint pauses are the false positives I referred to earlier, and are resolved by an indirect sensor. Retracts won't set off the unload sequence. As for your loading issue, please post more information, as I don't think that's how the current firmware works.
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
I did some more digging and found a couple of examples similar to what you mentioned. That's a firmware bug and has little to do with the sensor itself.
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
I haven't reviewed the firmware - I'm only surmising based on how the firmware interacts with me when trying to use the sensor. A few attempts to use it as intended is usually frustrating enough I can't find OFF fast enough. When 3.5 came along, I was hopeful the operation was improved, but for me the sensor became even more finicky; and I again turned it off.
I have parts for the new S mods, but there have been reports of even the new sensor not working as expected: problems of multiple loads required when changing filament. I am suspicious the same human factor is not dealt with, So I am waiting for a bit before installing. At some point I should open up the source and see how the sensor operation is actually coded. But I really want use the printer, not develop the printer.
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
That's a firmware bug and has little to do with the sensor itself.
I think this is exactly the issue Tim is trying to point out. PR wasn't able to solve all the issues with the sensor. You can call it firmware bug, design flaw or just wrong sensor for this purpose. The thing is that you will have most likely a hard time writing the firmware/software to make this sensor work as expected to 100%.
Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
There are several issues at play, and I think we should avoid mixing them up.
1) The sensor is picky about filaments. This is resolved through giving it something nice to look at, such as a bearing.
2) There is a bug in firmware that can sometimes set off the runout detect during autoload. This is a firmware bug and has nothing to do with the sensor, except for the fact that the code is a bit more complex than for a simple on/off sensor.
The only niggle with the sensor itself IMO, is that it's picky with filaments, and that's resolved. Firmware bugs are another matter. IMO this sensor is actually ideal (when used in indirect mode) for its purpose, as the ability to detect motion has far more potential than a simple on/off presence sensor.
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
That's a firmware bug and has little to do with the sensor itself.
I think this is exactly the issue Tim is trying to point out. PR wasn't able to solve all the issues with the sensor. You can call it firmware bug, design flaw or just wrong sensor for this purpose. The thing is that you will have most likely a hard time writing the firmware/software to make this sensor work as expected to 100%.
You're conflating a lot there.
Whether or not the sensor is effective as a sensor (and it's very effective in indirect mode), has little to do with firmware bugs.
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
You're conflating a lot there.
Whether or not the sensor is effective as a sensor (and it's very effective in indirect mode), has little to do with firmware bugs.
It's very simple quotation. solution = hardware + software
If the solution doesn't work reliable, you can blame one or the other or both. At the end of the day everything need to work hand in hand to provide reliable solution.
Just the fact that there are still open bug reports in regards to this "simple function" after one year is an indicator that this sensor is maybe not ideal for this purpose.
Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
You're conflating a lot there.
Whether or not the sensor is effective as a sensor (and it's very effective in indirect mode), has little to do with firmware bugs.
It's very simple quotation. solution = hardware + software
If the solution doesn't work reliable, you can blame one or the other or both. At the end of the day everything need to work hand in hand to provide reliable solution.
Just the fact that there are still open bug reports in regards to this "simple function" after one year is an indicator that this sensor is maybe not ideal for this purpose.
Rubbish.
That's like me saying that as there is are reports that the new sensor from the Mk3s is not working, that it's not ideal for it's purpose. Obviously such a statement would be pretty silly.
You can't just conflate every possible problem together and conclude that something is "not ideal for this purpose". You need to do a little bit of critical thinking, identify exactly what problems exist and what their causes are. Only then can you claim that something is not fit for purpose.
What you end up with is:
Is the stock, older filament sensor fit for purpose? - No. It has trouble with some filaments.
Is the indirect filament sensor fit for purpose? - Yes. It properly detects motion and is not confused by filaments.
The presence of bugs in the code has little relevance on whether a sensor is fit for purpose. Otherwise you end up with the ridiculous argument of 'This indirect filament sensor, which works perfectly to detect motion, regardless of filaments, is not fit for purpose, because there's a bug in the firmware that occasionally activates runout during loading'.
The solution in that example is obviously to fix the bug, not blame the sensor.
Re: How to use: 3D Printer Filament Detection Sensor Run-out Monitor Prusa i3 mk3
Just to expand on the above post, and why you can't lump everything together, consider this example.
I design a temperature logger.
I use a decent temperature sensor, and link it up to an arduino.
The temp sensor reports temps in ºC.
I decide to make the Americans happy and show temp in ºF, but I stuff up the conversion and it reports 10ºF higher than it should.
Does this mean the temperature sensor is not fit for purpose? Obviously not. The temp sensor works fine. What it means is that I would have to fix the bug.