A simple filament detector that pauses the printer and waits patiently to be fed more filament.
The instructions I've provided are for a Duet-powered Tevo Little Monster. Perhaps someone can comment on how to work with the stock Smoothie. Here's a head start: http://smoothieware.org/switch#pause-when-out-of-filament
Tevo LM Filament Guide v4 - Detector.stl - Trimmed .5mm off the diameter and fillet the front so it should be easier to snap into place but still be fairly snug. Thanks, AK_Eric.
Bill of Materials
Obtain the following materials:
- (1) print the part, obviously
- (1) SPDT roller rocker switch (http://amzn.to/2AnCN2c)
- (1) piece of 2 conductor wire long enough to reach the switch and mainboard
- (1) 3pin Molex KK plug w/ (2) ferrules (should have an extra leftover in your Duet kit)
- (2) M2x20 bolts w/ nuts (M2.5 are shown, it's all I had and I had to drill out the holes in the switch to accommodate)
- (2) M3x6 bolts
Makeup the plug
Fortunately, the polarity isn't an issue so solder/connect the 2 conductors on one end of the wire to the Normally Closed (NC) leads of the rocker switch. Use some heat shrink or electrical tape to protect the leads. On the other end, connect the ferrules and insert into pin 1 & 3 slots on the plug.
Install switch to grommet
Slide the switch into the bracket with the roller facing down (towards the grommet). Fasten the switch using the bolts and loosely tighten the nuts for adjustment.
Tip: you may want to put a drop of sewing machine oil on the roller because it will start to squeak over time. #experience
Adjust the position of the switch
Using a piece of filament, position the switch till you hear a click or use a multimeter to test continuity. I found tilting the switch back slightly offered maximum actuation while still making it easy to thread the filament through.
Install the bracket
Push the bracket through the underside of the top plate. Align the holes of the bracket to the preexisting holes of the bracket. Use the M3 bolts to fasten the bracket to the top plate.
Tip: use an Allen wrench to help guide the bracket into place since it's a tight fit.
Plug into the mainboard
With the printer off, plug the Molex KK into the E1 Stop jack.
Configure the sensor
Add the following to config.g file anywhere before the M501 command:
; Filament Sensor
M591 D0 P1 C4 R20 ; configure extruder drive 0 to use E1 endstop (C4) with 20% tolerance
M591 D0 ; display filament sensor parameters for extruder drive 0
If all is working you should receive the following popup on DWC with the print paused.