Lollipop Mechanical Door Knocker (with a Smile)【Description】Meet the Lollipop Mechanical Knocker! A fun, interactive, and cute mechanical gadget designed for your bedroom door, office, or workspace. Featuring a minimalist semi-circle housing, it cleverly uses the cord outlets to form a playful smiley face, bringing joy to every single knock.

【How It Works】It utilizes a clever dual-cord pull mechanism. By alternately pulling the two strings below, it rotates the internal shaft, driving the lollipop mallet to swing back and forth and knock crisply on the door. No batteries, no sensors—just pure mechanical satisfaction! 【Design Highlights】Playful Aesthetics: The cord outlets and shell cutouts blend seamlessly into a natural, healing smile.

100% Support-Free: Optimized extensively for 3D printing, this model requires zero supports. It's incredibly easy to print and clean up.

Smooth Engineering: Designed with strict mechanical clearance to ensure smooth shaft rotation, solid striking force, and long-term durability.

Important Assembly Tip:3D printed moving parts usually have a tiny bump at the Seam. Please make sure to slightly sand down the joint area with a small file or sandpaper before assembly, or it might catch a bit. Proper sanding will make the mechanism buttery smooth!

3D Printing & SettingsMaterial Recommendation: PETG is highly recommended for its toughness and durability.Print Settings: Simply use your slicer's default printing profiles; no special adjustments are needed.Post-Processing: Moving and transmission parts will have tiny bumps at the print seams. Please slightly sand or file down these seam areas before assembly to ensure buttery-smooth rotation.Hardware & BOM (Bill of Materials)Screws: 2 x M3 Shoulder Screws (Specification: $4\text{mm}$ shoulder diameter, $16\text{mm}$ shoulder length). Note: A matching hex key/wrench is required for assembly (not included).Strings: 2 x 1.5mm Braided Cords/Strings.Crucial Selection Guide: The internal cord channels have a diameter of $2.5\text{mm}$, so your strings must NOT exceed 2.5mm. Avoid using strings that are too thin as they might hurt your hands, and NEVER use elastic strings as they stretch and will cause the mechanism to jam.Mounting: Double-sided tape is required to mount the knocker onto the door. 3M VHB tape with a thickness of 1mm or more is highly recommended for a secure hold. Troubleshooting & WarningWhat to do if it jams:If the strings are pulled too quickly, they might occasionally get tangled or jammed inside the housing. If this happens, simply remove the outer cover and straighten the strings manually to restore smooth operation.