4 layers29.8 × 68.1 mm

BDEcho AKit Sidekick r3
Boondock-Echo/Boondock-Hardware
Hardware Design Files, BOM, Assembly Instructions, etc.
49 parts12
Boards in 1 GitHub repository, designed in KiCad, that use the SP-3541 by CUI (-25℃~+70℃ 12V 1A 3.5mm headphone jack Brass 插件 Audio Connectors ROHS). See how each wires it, with its parts, size, README and files; the SP-3541’s symbol, footprint and pinout are on its own page.

Boondock-Echo/Boondock-Hardware
Hardware Design Files, BOM, Assembly Instructions, etc.