Out of filament ALARM

This is a simple way to know you are out of filament, I´m using a momentary switch Cherry and I have uploaded the dimensions in case someone has a similar switch.

The idea is to use an Arduino Attiny85 with a buzzer to make the alarm sound as soon as the filament is getting close to finish

Here you have the video of the filament alarm working:
http://youtu.be/QGUehV8nUc4

If there is anyone who wants the Arduino code for the Attiny85 you can let me know and I´ll be posting it here or in my blog. Also I have the Schematics and the layout in case anyone wants to make a PCB with the Attiny85 microprocessor.

Here are the files:
STL and the Arduino code
https://drive.google.com/open?id=0B7dtMeeMPK5rfmE2WlctNEdWZkc1US1TTWFJblYyanJ1SExwczRtX1UyQjhJYTlqUlk2dUE&authuser=0

Attiny85 PCB and Schematics
https://drive.google.com/open?id=0B7dtMeeMPK5rfm55TGxFMGdVRXlXcmVkd2I5WVJLcURFbjh3UjlXckNxdjhpYkNVQmd1QkU&authuser=0

The Attiny programmer Layout and Schematics
https://drive.google.com/open?id=0B7dtMeeMPK5rfjgyemtrUUUxRTRSVHZNd0F1U3dLZ1JybXZFbzNkS0VYN2xQbnY4NjNobDg&authuser=0