Cheap (very) Filament-Out Alarm

This is a cheap way to throw together an alarm to let you know when your filament runs out. It consists of an inexpensive, battery-powered window alarm and an ultra mini micro switch. The alarms are widely available, often for about 2 for $5. I've even found them for $1 at the local Dollar Store. The switches are available on ebay for a few cents each. I used 2 half inch long 2-56 screws to hold everything together.

The micro switch is simply wired across the reed switch in the alarm. W