Dual-Chamber Bottle Cap Design

I need a production-ready concept for a dual-chamber bottle cap whose primary purpose is, quite simply, being a dual-chamber cap. The outer chamber behaves like any normal closure, but hidden inside is a second, sealed compartment that holds a secret powder. The moment the consumer twists the cap open, the mechanism must automatically release that powder so it drops cleanly into the liquid below.

Here’s what I expect:
• A complete 3D design (STEP or similar) suitable for injection-moulded plastics.
• An internal release mechanism that stays leak-tight in transit yet reliably triggers on first opening.
• Advice on materials, food-grade seals, tamper evidence, and optional child-resistance.
• Rendered visuals plus an exploded view that clearly explains assembly for tooling and manufacturing.

If you can also suggest quick prototyping methods (e.g., SLA prints with food-safe coatings) let me know, though the core deliverable is the CAD package and mechanism logic. I’m ready to iterate quickly, and I’ll provide prompt feedback to move us toward a functional, manufacturable cap.