A light-up LED bowtie for those moments when you want to be elegant, classy, and hard to ignore.

What you'll need

• 1× CR2032 battery

• 2× 5 mm ultra-bright LEDs (any color)

• ~60 cm elastic fabric string (6–8 mm wide)

• 10–12 mm bra-strap adjustment buckle (hook + loop)

A few notes on the LEDS: 

• 3 mm LEDs will work if that’s what you have lying around, but 5 mm are brighter.

• Don’t mix different colors. Vf differences can cause uneven brightness or even damage the LEDs.

• Color-changing LEDs are fine (slow-change ones look best), but they won’t stay in sync no matter what.

• Watch polarity: the longer lead goes to the flat back side, the shorter lead to the protruding face.

• You might need to trim the leads if your LEDs are in the "long leads" style.

• If contact is finicky, bend the leads slightly inward at the center, then back outward.

  

Print settings:

• Material: clear TPU (pretty much required)

• 2–3 walls

• No infill for the side parts

• ~15% gyroid infill for the center

• Prints fine without supports, but you can add a single tree support on the back hook if you want

• Use a .16 mm height on the sides and a .12 mm on the center. The images are from a draft print, thicker layers do some defect on the sides. Thinner layers become too milky.  

If you have issues with printing TPU on your Bambu... though luck, choose a better printer next time.  

Assembly:

• Insert the battery into the holder (flat side facing the back).

• Slide the LED leads into the holes on each side of the center piece, making sure they’re aligned correctly.

• The leads cross inside the body slightly off center, so if you feel resistance, adjust and wiggle the LED until it finds its spot.

• If everything works, push the sides into their slots

• Note the sides are different: one is V-shaped, the other cross-shaped.

Done. 

A single CR2032 battery should last a few days.