Show HN: Making a flexible "neon" t-shirt with LED filaments

Earlier this year I had the perfect excuse to experiment with some flexible LED filaments that had been sitting in my “interesting parts” bin for years -- the company I work for was putting on a neon-themed event, so obviously I had to custom-build some LED neon attire! The only problem was this was announced less than a week in advance.... This is how I designed and assembled a wearable neon shirt in just a few days.

A rough parts list, in case you want to try something similar:

Now that I’d validated a basic technique I had to actually design my "neon." One of the main constraints with these LED filaments is that they can't be cut to length - one end is positive and the other negative - and there’s no way to shorten them without completely breaking them.

This meant the path for my neon design needed to fit one of the discrete sizes. On the back of the shirt I wanted a llama using a single 24v 1200mm long red filament. I started with a continuous path in Inkscape (looping back and over itself as needed), then used Inkscape’s “Measure Path” feature to check the length and scale it until it was just about the right length.