We’ve been working on a little something 
Cool!
what chip are you using? And what do you meassure? [edit] ok found it http://www.pixart.com/upload/PAT9125EL_GDS_V1.2_31052017_20171011150843.pdf it is surface tracking … not diameter…
that chips max is below 50mm/s ( 16mm/s at 1mm distance) so you can’t track retractions proper?
Also, as it’s using IR, you might have trouble in picking up materials like TPU or Nylon. Which are pretty much transparent for IR.
3.3v? – The Prusa i3 is more complicated because it’s got a 5v -> 3.3v buffer on it. I’d love to grab one of these if you’ve got something communicating with it properly.
@ThantiK I dropped the regulator and buffer as with the LPC1769 used on smoothie, it’s a 3.3V system.
Where’d you source the actual part? I can’t find a distributor.
Did you gut an optical mouse for that? I have figured for a while now that it is cheaper for people to make things in small quantities by salvaging parts from finished goods than it is to order the parts.
He can probably scale down the movement with a set of gears if necessary. That would make implementation a little harder though since the gears would need to actually have traction on the filament.
@NathanielStenzel this is not like a normal optical sensor in a mouse (at least to my knowledge). Different way of communicating and probably more in the realm for cost. We need extremely accurate sensors to measure filament, so the optical sensor from a mouse might not be able to actually track an object under 2mm in diameter passing over its lens.
@ThantiK that would be a better question for Shai honestly. As these are pretty specialized components I wouldn’t be surprised if you just ordered directly from the manufacturer.
@Griffin_Paquette I always assumed that the mouse had a lense on it to widen the range of view.
@Griffin_Paquette Just used a filament (∅1.75mm) on 2 different mouse Sensors (blue and red light) - works well! And they are fast enough too. For ∅ controle you still would need a camera with optics on maybe a raspberryPI or ARM. Maybe a line sensor would work too but you wouldn’t get speed readings.
@Ulrich_Baer interesting! I was not the one who chose this sensor so I can’t really tell you why this was the one picked.
This is the kind of stuff I really am excited to see implemented in printers. I’m sure Shai will keep everyone up to date on how it performs. I would rather not double post.
@Griffin_Paquette I assume this is a PLA issue - never needed such a sensor, never had transport issues. But this would be a great improvement if the sensor is at the hotend of a bowden setup - it still wouldn’t help to print very soft TPU but i would imagine you get much better controle.
@Shai_Schechter , are these going to be purchasable soon?
@ThantiK Yes hopefully soon. Need to send one to @Wolfmanjm to implement into smoothie and test. Will only work for smoothie initially.
@Shai_Schechter that’s why I inquired – internally we’re testing with Klipper, we don’t need a supported one - I need a totally unsupported one so I can understand their characteristics, get it working on the Pi, etc.
@ThantiK I have heard quite a lot about Klipper recently. How does it compare to smoothie overall?
@Griffin_Paquette It’s basically just a really good hack to continue using old 8-bit controllers for motor timing and moving all the logic out into a higher level language.