BIGTREETECH Smart Filament Detector V2.0 - BTT SFS Sensor Detects Filament Break/Runout/Jam/Tying for 1.75mm Use with SKR Mini E3 V3.0, SKR 3, Manta E3EZ, Octopus Pro

Oddly shaped but smaller then I imagined it. Works flawlessly with klipper. Set it to 3.00mm, as the instructions recommended, instead of its advertised accuracy. I've printed a lot since installing and haven't had any false positives. Would by again. Also my main board is a btt skr mini e3 v3 running klipper on pi.

I bought the SFS V2.0, not the V1.0 which many reviews complained about. The V2 improves on the design flaws of the V1. The trigger pressure applied on the filament itself has never resulted in a jam thus far. However, BTT failed to provide sufficient documentation for older boards like SKR 1.3, 1.4, 1.4 turbo.I have a SKR 1.4 Turbo board with TMC 2209 drivers. To get this working with the latest Marlin (2.1.2) there were several things required:1) TMC2209 drivers or above need the 'diag' pin disconnected for E0 stepper drivers. This is a requirement for all other endstops to work as well, and has been documented in the BTT github repo for the BTT TMC2209 V3 stepper drivers.2) The documentation states to plug the motion sensor pins to E0DET and the switch sensor to to E1DET. This is WRONG. They must be swapped. This took me a very long time to figure out and was the main reason for troubleshooting issues. The switch sensor needs to be plugged into E0DET and motion sensor to E1DET, or you can re-map them digitally like I did by explicitly declaring the pin outputs for FIL_RUNOUT_PIN and FIL_RUNOUT_PIN2 respectively.3) I had to invert the endstop logic for the filament runout sensor. Instead of LOW I had to have it HIGH.4) You can find the STEP files on their SFS 2.0 github repo to design yourself a custom mount for your printhead. I have a direct drive setup, so I extended the X-Carriage backplate taller to fit a mount for the new sensor. It is easier to import the STEP file in CAD than measuring it out with a caliper, which is what I did initially before discovering the STEP file.Using this new device, I successfully have motion tracking and runout tracking working after many tests. It seems very reliable. I've had no issues with the actual device, except the lack of documentation which lost me 4 days figuring out with trial and error.Here is my configuration.h snippit for enabling the sensor. I hope it saves other people more time with other boards. Keep in mind I remapped the E0DET and E1DET pins instead of physically swapping them on the board.#define FILAMENT_RUNOUT_SENSOR#if ENABLED(FILAMENT_RUNOUT_SENSOR) #define FIL_RUNOUT_ENABLED_DEFAULT true // Enable the sensor on startup. Override with M412 followed by M500. #define NUM_RUNOUT_SENSORS 1 // Number of sensors, up to one per extruder. Define a FIL_RUNOUT#_PIN for each. #define FIL_RUNOUT_STATE HIGH // Pin state indicating that filament is NOT present. #define FIL_RUNOUT_PULLUP // Use internal pullup for filament runout pins. //#define FIL_RUNOUT_PULLDOWN // Use internal pulldown for filament runout pins. //#define WATCH_ALL_RUNOUT_SENSORS // Execute runout script on any triggering sensor, not only for the active extruder. // This is automatically enabled for MIXING_EXTRUDERs. // Override individually if the runout sensors vary //#define FIL_RUNOUT1_STATE LOW //#define FIL_RUNOUT1_PULLUP //#define FIL_RUNOUT1_PULLDOWN //#define FIL_RUNOUT2_STATE LOW //#define FIL_RUNOUT2_PULLUP //#define FIL_RUNOUT2_PULLDOWN //#define FIL_RUNOUT3_STATE LOW //#define FIL_RUNOUT3_PULLUP //#define FIL_RUNOUT3_PULLDOWN //#define FIL_RUNOUT4_STATE LOW //#define FIL_RUNOUT4_PULLUP //#define FIL_RUNOUT4_PULLDOWN //#define FIL_RUNOUT5_STATE LOW //#define FIL_RUNOUT5_PULLUP //#define FIL_RUNOUT5_PULLDOWN //#define FIL_RUNOUT6_STATE LOW //#define FIL_RUNOUT6_PULLUP //#define FIL_RUNOUT6_PULLDOWN //#define FIL_RUNOUT7_STATE LOW //#define FIL_RUNOUT7_PULLUP //#define FIL_RUNOUT7_PULLDOWN //#define FIL_RUNOUT8_STATE LOW //#define FIL_RUNOUT8_PULLUP //#define FIL_RUNOUT8_PULLDOWN // Commands to execute on filament runout. // With multiple runout sensors use the %c placeholder for the current tool in commands (e.g., "M600 T%c") // NOTE: After 'M412 H1' the host handles filament runout and this script does not apply. #define FILAMENT_RUNOUT_SCRIPT "M600" // After a runout is detected, continue printing this length of filament // before executing the runout script. Useful for a sensor at the end of // a feed tube. Requires 4 bytes SRAM per sensor, plus 4 bytes overhead. #define FILAMENT_RUNOUT_DISTANCE_MM 10 #ifdef FILAMENT_RUNOUT_DISTANCE_MM // Enable this option to use an encoder disc that toggles the runout pin // as the filament moves. (Be sure to set FILAMENT_RUNOUT_DISTANCE_MM // large enough to avoid false positives.) #define FIL_RUNOUT_PIN P1_25 #define FIL_RUNOUT_PIN2 P1_26 #define FILAMENT_MOTION_SENSOR #define FILAMENT_SWITCH_AND_MOTION #endif#endif

Even when you have a direct drive extruder and and filament switch right inside the tool head, a normal filament switch won't detect an issue if your filament is stuck. This is where this beautiful device comes into play. It detects the presence of the filament just like a normal filament switch but it also detects the movement of the filament. So, if your filament gets stuck and your extruder just starts to dig into the sides of the filament and slowly eat it away from the sides, this will detect the issue before anything goes horribly wrong and you loose your print. You need to make some configuration changes on your printer (I use klipper so it was easy for me) and you will need an additional input to your board if you want to use both motion and normal filament sensor, but it is worth it. I've installed this into my K1 max (which required some soldering on the board to get additional input) and now, I'm really happy with the results. I've 3Dchamelion installed and due to additional bowden tube length and some added friction from the 3d chameleon sometimes the filament just gets stuck. Extruder tries to push it but cannot pull it due to friction and all the while normal filament sensor would not warn you because filament is there. This however, catches problem if the movement of the filament does not match speed of the extrusion. It has already saved two of my prints.

I grabbed the BIGTREETECH Smart Filament Runout Sensor V2.0 for my Voron 2.4 running Klipper and I must say, it’s been a practical addition to my setup. Installation was pretty straightforward which was a relief. I was able to get it up and running in no time, and it integrated well with my existing setup.The sensor has been doing its job in reducing print errors. It's caught a couple of filament runout situations and saved me some potential headaches. The feature where it can detect not just filament runout but also breakage and clogging is something I find quite useful. It’s nice knowing that it's monitoring and will halt the print if something goes awry.One thing that stood out to me was the bilateral feeding feature. It’s a small thing but it does make the installation and filament feeding a tad bit easier, not having to discern between filament inlet and outlet.The sensor is lightweight, so I didn’t notice any added inertia to the direct-drive extruder which was a concern initially.I haven’t had to deal with false triggers so far, so the sensitivity of the sensor seems to be well-calibrated for my use.All in all, the BIGTREETECH Smart Filament Runout Sensor V2.0 has been a handy addition to my 3D printing setup. It’s been working as advertised, helping to catch filament issues early and save me from failed prints. It’s a small piece of hardware that’s added a bit more reliability to my printing process.

The first one I got stopped registering filament after just a few filament swaps. I replaced it with another and haven't had any issues since then. It's great for knowing when there is filament in it and whether the filament is moving like it's supposed to.