Low-Noise Watch Timegrapher Stand (TPU Decoupled)

An ultra-low-noise timegrapher stand engineered to outperform commercial clip-on microphones. By isolating the measurement cell within a floating TPU Gyroid sandwich and transferring acoustic impulses directly through an adjustable M3 brass contact pin, this design completely eliminates desk vibrations, fan hum, and structure-borne noise.

Universal Compatibility: Works seamlessly with PC software (e.g., TG Timegrapher) as well as mobile devices using apps like "Watch Accuracy Meter" via USB-OTG or jack adapter.

Key Features

• Floating Mechanical Cell: The 27mm piezo disc rests on a soft TPU ring, completely decoupled from the main housing.

• Direct Metal-to-Metal Impulse Transfer: An adjustable M3 brass contact pin bridges the watch case directly to the piezo disc for maximum signal clarity.

• Integrated TPU Dampening: Gyroid infill in the TPU isolation layer acts as an acoustic low-pass filter against desk vibrations.

Pro-Tip: Dial-Down Regulation & Glass Protection When regulating a watch movement face-down with the case back removed, the glass rests directly on the central pin. To prevent scratches on delicate acrylic or mineral crystals:

• Clear Tape / Protective Film: Place a small strip of thin clear tape (or polyimide/Kapton tape) directly over the M3 brass tip.

• Signal Impact: Real-world testing shows this reduces acoustic signal strength down to ~50–75% due to the adhesive layer, but because the stand's base SNR is so high, the signal remains perfectly crisp and accurate in both TG Timegrapher and Watch Accuracy Meter.

• Best Practice: Center the watch glass directly over the brass pin for optimal impulse transfer.

Bill of Materials (BOM)

3D Printed Parts:

• PETG: Base Housing, Piezo Mount (~20g total)

• TPU: Isolation Layer, Piezo Ring, Top Pad, 4x Feet, Watch Strap (~10g total)

Electronics & Hardware:

• Pos 03: 1x 27mm Piezo Element

• Pos 04: 1x 3.5mm AUX Cable (1.0–1.5m)

• Pos 05: 1x Piezo Ring (TPU)

• Pos 06: 1x Piezo Mount (PETG)

• Pos 07: 1x TPU Isolation Layer (TPU)

• Pos 08: 1x Main Base (PETG)

• Pos 09: 1x TPU Top Pad (TPU)

• Pos 10: 4x Foot (TPU)

• Pos 11: 1x TPU Watch Strap (TPU)

• Pos 12: 8x M3x4mm Button Head Screws

• Pos 13: 4x M3x6mm Button Head Screws

• Pos 14: 1x M3x6mm Countersunk Screw

• Pos 15: 1x M3 Brass Heat-Set Insert (~6.5mm length)

• Pos 16: Plastic Glue

• Pos 17: Super Glue (Cyanoacrylate)

Recommended Print Settings (0.4mm Nozzle)

Assembly Instructions

1. Preparation: Check and clean all printed holes and M3 threads with a tap or screw if necessary.

2. Cable Routing: Feed the stripped, un-terminated end of the 3.5mm AUX cable (Pos 04) through the side hole of the main base (Pos 08) and through the Piezo Mount (Pos 06).

3. Piezo Wiring: Solder the AUX cable signal wire (red & white bridged) to the white ceramic center (positive) of the piezo disc (Pos 03), and the ground shield to the outer brass ring (negative).

4. Acoustic Pin Setup: Apply a thin layer of super glue (Pos 17) to the center of the piezo's brass side and attach the M3 countersunk screw (Pos 14) with the head to the brass side. Thread the M3 brass insert (Pos 15) onto the screw.

5. Cell Assembly: Seat the piezo element (Pos 03) into the TPU piezo ring (Pos 05), then insert this assembly into the piezo mount (Pos 06). Route the wires through the side notch. Fasten Pos 06 to the TPU isolation layer (Pos 07) using 4x M3x6 screws (Pos 13).

6. Base Setup: Screw the 4 feet (Pos 10) to the bottom of the main base (Pos 08) using 4x M3x4 screws (Pos 12). Glue the TPU top pad (Pos 09) onto the main base (Pos 08) using plastic glue (Pos 16).

7. Final Integration: Secure the TPU isolation layer (Pos 07) to the main base (Pos 08) with 4x M3x4 screws (Pos 12). Pull any cable slack gently through the side wall.

8. Strap Attachment: Hook one side of the TPU strap (Pos 11) onto the base side-tabs.

Calibration & Software Setup This stand provides an ultra-clean signal without background noise, making it fully plug-and-play across multiple platforms:

• Mobile Setup (Android / iOS): Plug into your phone (via USB-OTG audio dongle or 3.5mm jack) and open Watch Accuracy Meter. Set your movement's lift angle and measure instantly right on your workbench—no PC required!

• PC Setup (Windows / Mac / Linux): Connect to your sound card (Line-In / Mic-In) and open TG Timegrapher or Klockalyzer. Set your microphone input level to 60–70% for a crystal-clear waveform without preamp hiss. Adjust threshold gain until the baseline is completely flat.

• Hardware Calibration (Height Adjustment): Thread the brass tip (Pos 15) until it protrudes 0.5–1.0 mm above the TPU top pad (Pos 09). Lock it with Teflon tape or a thin M3 jam nut if needed to ensure solid contact with the watch case.