Sounds like a project that could really light up the gym, literally. I’d start with a tiny microcontroller, maybe an ESP32, just so you can stream audio and pull the beat. Then pair it with a tiny accelerometer so it reacts to your motion, not just the music. Use diffused LED strips instead of bright spotlights—soft, warm colors feel more like a garment than a flashlight. And don't forget a flexible PCB or a conductive thread layout that can bend without breaking the signal. The trick will be timing: you’ll need a short, low‑latency audio‑to‑LED loop, maybe a quick FFT or a simple beat‑detection algorithm, so the lights keep pace. Just keep the wiring tidy and the layers as thin as possible, and you’ll have a vest that feels like an extension of your body, not a tech cage. Happy hacking!