Penne 2.0 – Public Domain Safety Whistle (CC0)

I created this compact, powerful safety whistle from scratch to be freely shared with anyone who needs one — no questions asked.

Penne 2.0 is an evolution of the original design, refined through real-world printing, large-batch distribution, and community feedback. The goal remains the same:
turn quiet into the safety of sound.

Thanks to  M_D_K  on Thingiverse for making a customizable openSCAD version of the Penne 2.0 please feel free to customize settings including messaging. 

What’s New in Penne 2.0

• Reinforced lanyard area
  Stronger top and bottom walls around the lanyard inlet for improved durability.
• Longer mouthpiece tip
  Easier, more consistent airflow for better success across all users.
• Reduced weight: ~1 gram per whistle
  Makes bulk counting, weighing, and distribution significantly easier.
• Optimized plate grouping
  Fewer merged groups to allow skipping and flexibility in Bambu Studio.
• Improved first-layer reliability
  The first millimeter is tuned for slower, steadier layers to reduce early failures when printing in bulk.

Why This Exists

Whether you’re boating, hiking, camping, running, training scouts, organizing events, or simply standing up for your own safety and voice — this whistle is designed to be there when you need it most.

This design is Public Domain (CC0).
You are free to:

• Print it
• Share it
• Remix it
• Distribute it
• Sell prints or give them away

No attribution required. No restrictions. Ever.

If you’re part of a community, school, scout group, mutual aid network, or safety-focused organization, you are encouraged to print and distribute these in bulk. These whistles have already reached tens of thousands of people, and they continue to spread thanks to makers like you.

Files & Custom Layouts

All STL files are provided below.

If you want a version optimized to maximize your specific print bed, message me with your printer dimensions and I’ll generate a layout for you.

Don’t Have a 3D Printer?

You can still get a whistle.

• Chicagoland area: anonymous local drop options available
• Worldwide: printing and shipping available via Slant3D (paid option)

No questions asked.

Recommended Print Settings

• Nozzle: 0.4 mm
• Layer Height: 0.24 mm
• Walls: 2–3 (Arachne)
• Infill: 100% (for maximum tone consistency and durability)
• Supports: None
• Material: PLA+ or PETG

Tips & Bulk Printing Recommendations

When printing many small parts on a single plate, first-layer reliability matters more than usual.

These whistles are often printed in large quantities, which means:

• Your printer should be well tuned
• Your build plate should provide excellent adhesion

Strongly recommended:

• Bambu Cool Plate SuperTack (this has effectively eliminated adhesion issues on Bambu machines)
• Elegoo Centauri Carbon Side B “5-Star” plate

Standard PEI plates may not be sufficient on their own for high-density layouts. If you experience failures:

• Switch to a high-adhesion plate
• Or use appropriate adhesion aids

Start with a smaller batch, confirm reliability, then scale up as you gain confidence. These designs have been tested at scale, but your setup matters.