Topic: I made a Filament Out alarm
$15 worth of parts. I'm going tip put this on Thingy Verse if no one finds fault with it.
Kent's Filament Out Alarm (Fil-Out?) Instructions
This switch trips a pretty loud alarm if your filament runs out, giving you a couple of minutes to Pause your print job and put on another spool. It is independent of your printer's electronics and powered by one 9V battery.
It builds upon the Lawsy (thank you) filament valve Thingy as a mounting system and to keep filament from backing up in the switch on filament Retracts.
You will need:
1- NTE 54-409 SPDT switch, available from Micro Center and several places online for about $5. There are several variations of the alarm, so look around. One includes a strobe light which flashes when the alarm goes off.
1 - mini SPST toggle switch for Alarm On-Off
1 - 9V Battery
2 - M3 x 15mm screws with nuts.
2- 22-Ga crimp style slip-on spade wire connectors (usually with the red plastic sleeve). These slip right onto the switch.
1 - 130db (or whatever) Personal Alarm (about $5-$10 online) the type which activates by pulling out the wrist strap.
You will solder two 22-gauge (or so) wires onto the Printed Circuit Board in the alarm unit to replace the personal alarm's wrist lanyard pin with your switch. It is pretty easy to see the two contact points for the wrist-strap activation pin on the back side of the PCB.
Soldering iron, wire crimper.
See the attached pics for a better ubderstanding of the instructions.
The switch mounts on the PC pipe (in this Download) that holds your filament spool. That leaves enough filament between the switch and your hot end to give you time to Pause the print job and put on a fresh spool of filament before your print job is ruined.
The alarm connects to the switch's On-Off mini toggle switch then to the COM and NC terminals of the lever switch via several inches of wire and can be stuck on your printer cabinet with Velcro or two-sided tape.
Once you have your parts and printed pieces, it only takes about ten minutes to make this Thing.
NOTES: On the switch, bend the thin metal arm down 90 degrees about 8MM from the end. This ensures it can't catch on the plastic housing or the filament.
Feed the wire terminals thru the square hole in the switch box before you connect them to the switch. Then, press the switch into the locating bosses and screw it down.
Print these parts at high infill for strength. I suggest ABS at 70% infill.
Feel free to make your own mount or a cap for the switchbox if you like. I figured it would be off more than on and it's really not needed.
You could also use the Normally Open (NO) switch contact to light a flashing LED or a relay to stop the printer motors or to text you a message telling you it's a bad idea to leave your printer unattended. 