An open-source stethoscope that costs between $2.5 and $5 to produce

This project aims to create a research-validated stethoscope whose plans are available freely and openly. The goal is for the bell to cost ~USD$1-2 to produce, and the rest of the stethoscope to cost approximately the same. Currently, the stethoscope resulting from this project functions as well as the market gold standard, the Littmann Cardiology III.

Printed parts:

• 1 stethoscope head (head.stl)
• 2 ear tubes (eartube.stl)
• 1 Y-piece (y_piece.stl)
• 1 Spring (spring.stl)
• 1 Ring (ring.stl)

Other hardware:

• 50cm length of Silicone tube - 8mm ID, 13mm OD, 50 durometer
• 20cm length of silicone tube - 4mm ID, 8mm OD, 50 durometer
• Diaphragm: 40mm diameter cut from a report cover with approx 0.35mm plastic sheet
• Earbuds / Eartips: Any large-sized standard earbuds will do

Printing Specifications:

• INFILL MUST BE 100% (Otherwise, the stethoscope will not produce a correct sound!)
• Use PETG or ABS (Do not use PLA due to heat deformation)
• Layer height: 0.2mm
• Use PrusaSlicer 2.0 or above to import 3MF file

Assembly Instructions:

• Attach the diaphragm (40mm) to the stethoscope head.
• Attach the stethoscope head to the silicone tube.
• Attach the silicone tube to the Y-Piece.
• Attach spring to ear tubes.
• Attach the Y-piece to the ear tubes.
• Attach the ear tubes to the eartips / earbuds.
• Test the stethoscope as per the validation instructions.

CrystalSCAD and OpenSCAD were used to create all STL files. To recreate the stethoscope head, use:

gem install crystalscad
ruby source_files/stethoscope_head/stethoscope_head.rb

The project is presented under the TAPR OHL license.