I was looking into building something like this: Roadrunner, but its 1.75mm version. Not sure if I could source gears for 2.85mm cheaply enough … anyone using sensor for 2.85 ? Also, how easy/hard is to connect it to the Rambo board ?
Hold up it you want to run 1.75 on most lulzbots all you need is a new toolhead I do the same on my taz workhorse & Taz workhorse+
I made some slight modifications to the Big Tree Tech Smart filament sensor: BigTreeTech Smart Filament Sensor Mount for Lulzbot Taz 6 by Wrathernaut | Download free STL model | Printables.com
It was available for under $15 when I got it, but they’ve moved to the SFS 2.0 and the older one is harder to find. If you’re into DIY’ing a solution, all you need a way to generate an alternating on-off signal from filament movement. This could be as simple as a completely passive idler that has a cam that hits a microswitch as it rolls, or as complex as an optical encoder like a mouse uses for the scroll wheel.
For the SFS 1.0 I used, the sensor takes in a +5v signal, and just alternates opening and closing a circuit on a pair of wires which can be run to any of the unused endstops on the Rambo board. Marlin supports this natively as a filament sensor that detects movement instead of just runout.