Tiny Glowing Jar - Flexible LED Filament in an 8 ml Bead Jar

A small decoration that looks great in the dark: a spiral of flexible LED filament glowing inside a tiny 8 ml glass bead storage jar. I made several in different colours — red/orange, blue and green.

How it works

• The two CR927 coin cells sit in the base of the core, connected in series.

• The LED filament winds around the central post; its wire runs down through the hollow post to the batteries.

• There is no switch: the lid presses the end of the wire against the battery, which turns the light on. To turn it off, take the lid off and bend the wire away from the battery.

Parts to print (per jar)

• Core — base with the battery pocket and the hollow central post (15 × 15 × 42 mm)

• Lid (15 × 15 × 5 mm)

Bill of materials (per jar)

• 1× 8 ml glass bead storage jar

• 1× flexible LED filament, 60 mm long

• 2× CR927 coin cells

• A short piece of thin wire

Assembly

1. Put the two CR927 cells into the pocket in the base, in series.

2. Wind the LED filament around the post and pass its wire down through the hollow post to the batteries.

3. Insert the core into the jar and press the lid on: it pushes the wire end against the battery and the filament lights up.

Good to know

• Check the rated voltage of your LED filament: two CR927 in series give about 6 V. Coin cells can't deliver much current, which is what makes this simple setup work, but a filament rated much lower may run hot or fade quickly.

• CR927 cells are small, so expect hours of glow rather than days.

Print settings

• Printer: QIDI Q1 Pro, nozzle 0.4 mm

• Material: PLA (Wood-PLA turned out too brittle for such thin parts)

• Layer height: 0.2 mm, walls: 2

• Infill: 100 % — the parts are tiny, solid is stronger

• Supports: yes, tree (auto)

• Print time: about 15 min per part

• The Orca project still has Wood-PLA selected — switch it to regular PLA