This is a simple way to detect filament runout using a Zigbee Window Door Sensor. It’s designed to work with this sensor model but may be compatible with others.

How It Works

• A floating mount slides freely along the filament. When the filament runs out, it drops and triggers the sensor.
• A rubber band holds the floating mount and acts as a tensioner.
• A paperclip works as a safety release – if anything gets stuck, it will bend instead of breaking parts.
• A small foam pad cushions the sensor to prevent hard impacts.
• The case is attached to the filament dryer using double-sided tape.

Assembly Steps

1. Attach a rubber band to the cradle.
2. Insert the small part of the Zigbee sensor into the cradle and secure it with two small pieces of 1.75mm filament.
3. Thread the rubber band through the hole in the case.
4. Place the cradle with the sensor into the case.
5. Use a paperclip to connect the floating mount to the rubber band.
6. Attach the case to the filament dryer where the rubber band naturally rests without tension.
7. Pass the filament through the floating mount when loading it into the printer.