From the Loftsmith Workshop
NFC Christmas ornament with sealed tag pocket, 15-35 mm
A little tree for the Christmas tree that does something when you tap a phone to it. A round pocket in the middle holds an NFC tag, and a thin layer of plastic closes over the top. A raised white outline and three dots make it look like frosting. Set the tag size and the ornament grows to fit.
1 part · 7 g · 56 × 79 × 4 mm
Ask for the sizes you want to tweak, e.g. “make the width adjustable”.
How to print it
Parts
- ornament · PLA, matte green on the default tree (no · Flat, back face on the bed, raised face up. No supports: the pocket roof bridges over the tag.
Body with the sealed tag pocket. PLA because it is stiff, prints a clean flat bridge over the pocket, and the ornament hangs indoors.
- face · PLA, second colour (cream on the default · Printed as part of the ornament object, on filament slot 2.
Raised half-round beads: the rim, the ring round the tag and the dot baubles. It starts on the roof top, so it needs one filament change at the layer named in the check. Map both slots to one spool for a one-colour print. The 7 g does not include purge from the filament change; your slicer shows tha
Print settings
- Layer height
- 0.2 mm with a 0.2 mm first layer. These must match the Layer height and First layer height sliders, or the pause layer will be wrong.
- Walls
- 2
- Infill
- 15%
- Supports
- Off. If supports are on, the slicer fills the tag pocket.
- Notes
- About 7 g and 14 minutes at 2 walls/15% infill; the per-settings estimate for 2 walls/15% is about 8 g, 14 minutes. With 3 walls, about 10 g and 18 minutes. The 7 g does not include purge from the filament change; your slicer shows that amount. Pause before layer 12 (the slicer shows it as Z = 2.40
Hardware
- NFC tag, 25 mm round, about 1.0 mm thick (NTAG213, NTAG215 or NTAG216) · Set the tag sliders to the tag you own: 15-35 mm round or square, 0.15-1.6 mm thick. Sticker tags are about 0.15-0.2 mm. NTAG213/215/216 hold 144/504/888 bytes (NXP).
- Ribbon or ornament hook · Goes through the 5 mm hanger hole (slider 3-8 mm).
Assembly
- Program the tag with your link or video first and test it with your phone.
- Set the Layer height and First layer height sliders to your slicer profile, and the tag sliders to your tag. Read the pause layer and colour-change layer from the Pause height check.
- Slice with supports off. In the layer preview, find the layer named in the check (layer 12, Z = 2.40 mm at the defaults) and add a pause before it. Optionally add a filament change before the face layer (layer 18, Z = 3.60 mm).
- When the printer pauses, check that the pocket is open and clean, then drop the tag in flat. It should sit 0.2 mm or more below the top surface. Resume, and the roof prints over it.
- After printing, hold your phone flat against the face over the ring to check it reads, then thread a ribbon through the hanger hole.
Good to know
- Read range depends on the phone and the tag; hold the phone flat against the face over the ring. Test a tag through a cover of the same thickness before sealing one into a gift.
- The tag is sealed in for good and cannot be swapped out. You can still rewrite it through the plastic unless you lock it.
- The pause and colour-change layers are calculated for the layer heights you enter. Variable layer height, a different first layer or adaptive slicing will move them, so always confirm in your slicer's layer preview.
- The first roof layer bridges 26 mm across the pocket onto the tag. Expect a slightly rough underside, which is hidden inside.
- PLA softens at about 55 C, so keep it off hot lights and out of hot cars. The hanger loop is checked against a 2 kg tug, not for heavier loads.
- Don't use metallic, glitter or carbon-filled filament, because they may interfere with reading. The ornament itself contains no metal parts.
- If the tag is too big for the chosen size, the outline grows to fit it.
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