Filament Remaining sensor.



  • I was thinking a very useful feature is a sensor that will report how much filament is remaining on the spool.

    How i would propose this to be done, is have a lever setup that rests against filament on roll, other end to a potentiometer.

    That is wired to say Thermistor 7.

    You could then have set filament spool settings, Like diameter of empty spool and full spool, width of spool and diameter of filament.

    also then run a spool calibration which measure resistance of pot when spool is empty and spool is full.

    With that information you should be able to calculate how many meters of filament left.
    Doing it by weight wont work due to the variety of filaments.

    by knowing that and comparing the estimated gcode filament need, you can quickly see if you have enough filament left.

    What you all think?



  • Octoprint have a nice plugin that does that with good results and it is very simple. I would like to see something like that implemented to DWC

    Basically it get the length data from the printing information and manage a DB of spools. It is not precise but always worked fine for me - with errors to the safe side. Even warning when a spool had not enough filament before printing.

    https://plugins.octoprint.org/plugins/filamentmanager/



  • Nice idea! Such sensor is very easy to build...



  • Idea is you can get a partially full spool and put it in, and would have a rough idea how many meters are left.

    I can make a sensor and lever setup,

    just need some one to do the software and build it into the firmware.



  • Ok, I see what you mean! I agree, this is not that simple...



  • Found this some time ago.

    https://blog.adafruit.com/2018/05/24/spool-holder-weight-measure-3dthursday-3dprinting/

    I've not tested it nor checked how it works exactly. But if you have a tare weight of the spool it should be possible to get the remaining filament.



  • Why not to measure diameter of filament that left on the spool? Spring, some lever like ruler, potentiometer. If you are taking always the same manufacturer - you know diameter of full spool and empty. But will need to make some table as it will be non-linear



  • Math would be quite simple. A bit of trig... tons of examples out on Google.

    Central hub diameter, and "Width" of spool will be required inputs. Width might be measurable with a 2D arm. Central Hub may not be as crucial as we think, need to play with the math for some reasonable variance across manufacturers.



  • Maybe a guru in electronic could design something so the value read as temperature gives the remaining filament length (or weight) 😛 I'm sure it is possible, even tuning the center spool (empty value) with a variable resistor... So no firmware modification needed!


 

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