Ultra-Slim No-Neutral Smart Switch

I need a compact, single-fire line smart light switch designed around the ESP32-C3, strictly for residential use and housed in a PC-V0 enclosure. Because there is no neutral wire available the power stage has to ride on the leakage current, so I am counting on a proven AC-DC buck such as the Hi-Link HLK-PM01 (or similarly tiny module) and a reliable bypass-capacitor network that keeps the MCU alive even with very light loads attached. Switching must be silent and fast: think BTA16 (or comparable TRIAC) driven through an opto-isolated MOC3041 gate. Absolutely no mechanical relays are allowed. Behind the faceplate, the board should hide an HLK-LD2410 microwave radar sensor; its trigger will be combined with a capacitive interface that recognises multiple touch points on the glass front. Space is tight, so the PCB has to be extremely slim while still dropping neatly into both EU and US wall boxes. Bluetooth LE performance is critical: the first firmware drop only has to prove low-latency BLE control alongside a reliable radar interrupt, nothing more. Deliverables • Complete schematic and production-ready PCB layout (Gerber, drill, pick-and-place) • Clean, component-numbered BOM with LCSC or Mouser order codes • Minimal test firmware showing BLE command latency and radar wake-up response If you have experience squeezing ESP32-C3 designs into no-neutral form factors—and can keep EMC, thermal limits and touch sensitivity happy in one ultra-slim board—I would love to see your approach.

Project ID: 40262209