Stethoscope

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.

Bill of Materials

Printed parts:

• 1 stethoscope head (head.stl)
• 2 ear tubes (eartube.stl)
• 1 earplug mold (earplug_mold.stl)

Other hardware: Some vendors are suggested. See Bill of materials ODS file for more information.

• 40cm Silicone 12mm OD, 8mm ID

• 8MM I.D X 12MM O.D NGP60 Clear Translucent Silicone Hose Pipe Tubing (USD$6.95)

• 20cm Silicone 6mm OD, 4mm ID

• Silicone for ear plugs

• Moldable Silicone Ear Plugs (USD$1.80)

• Diaphragm: 40mm diameter cut from a report cover with approx 0.35mm plastic sheet

• Staples 21639 report cover (UPC 718103160223) (USD$8.84)

• You can cut the diaphragm by hand or with a stamp like this one

Optional hardware:

• Metal spring for holding ear tubes together

Print Instructions

INFILL MUST BE 100%

All printed parts should be printed with ABS or PLA plastic at 0.2mm layer height, though it is acceptable for the first layer to be 0.3mm.

We print the eartubes with a brim of 2mm to ensure that none of the parts lift off.

INFILL MUST BE 100%. Otherwise, the stethoscope will not print well.

Assembly Instructions

• Insert silicone into mold and allow to set as per manufacturer instructions.
• Attach the diaphragm (40mm) to the stethoscope head.
• Attach the stethoscope head to the silicone tube.
• Attach the silicone tube to the T-Piece.
• Attach spring to ear tubes.
• Attach the T-piece to the ear tubes.
• Attach the ear tubes to the molded earplugs.
• Test the stethoscope as per the validation instructions.

Changing and creating SCAD files

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

gem install crystalscad
ruby source_files/stethoscope_head/stethoscope_head.rb

The SCAD files output from CrystalSCAD are found in source_files/stethoscope_head/output and are named as follows:

• PrintableStethoscopeHead1Assembly_output.scad - The head
• EarplugMold_output.scad - Earplug mold

Other stethoscopes

Others have made 3D printed stethoscopes too. See:

• https://www.youmagine.com/designs/stethoscope-chestpiece