J2 is a JST VH-series, 3-position, 3.96 mm-pitch connector.
For the PCB, order:
- JST B3P-VH(LF)(SN) — vertical through-hole board header
For the mating cable, order:
- VHR-3N — 3-position receptacle housing
- SVH-21T-P1.1 — crimp terminals, one per wire
Pinout:
- +5 V
- LED data
- GND
Use suitably heavy wire for the LED power current; for a 3 A run, approximately 18–20 AWG is appropriate.