Clock Beat Stethoscope

An inexpensive alternative to a timegrapher. A 3D printed stethoscope to work with phone apps to set beat on clocks.

Whether you repair old clocks or 3D print mechanical clocks. The hardest thing is getting the beat set correctly by ear. Using this 3D printed pickup and a phone app, you can dial in even the weakest clock beat.

1. 3D printed parts
2. Low-cost $6 phone earbuds with microphone (compatible with your phone)
3. Short piece of 3/8 tubing

3D print base and pickup parts. Both print vertical with flat side down no supports.

The pickup has a 1mm diaphragm with the pickup stylus attached. The stylus passes through the cone with a very tight tolerance. I used 0.15 layer height and adjusted the flow to ensure the stylus pin is free.

Insert the mic portion of ear buds into 3/8 tubing.

I cut the ear pieces off for a cleaner look, and I got tired of them getting in the way.

(But not necessary and could short out the ear buds)

Slip 3/8 tubing with mic over nipple of base and carefully push pickup into base.

Care should be taken with pickup, if you put too much pressure on the stylus, you can crack the thin diaphragm.

Attach to phone. Use one of many apps for setting beat on mechanical clocks. My preferred app is ClockMaster-Time Regulator from ONYX apps.