designing-hardware-products

# Designing Hardware Products > From empty directory to shippable product. Requirements in, Gerber + .bin + .apk out. ## When to use | Scenario | Use | Why | |----------|-----|-----| | New IoT / embedded product from scratch | Yes | Full pipeline | | Adding BLE app to existing hardware | Partial | Phase 4 only | | PCB redesign with existing firmware | Partial | Phase 3 only | | One-off breadboard prototype | No | Overkill, just wire it | ## Pipeline phases ``` Phase 1: System Design → DESIGN.md (architecture, topology, protocol) Phase 2: Firmware → ESP-IDF components, FreeRTOS tasks, BLE GATT Phase 3: Hardware → KiCad schematic → PCB → route → DRC → Gerber Phase 4: Mobile App → UniApp (BLE, i18n, dev mode, SVG icons) Phase 5: Verify + Package → build all → zip release ``` Each phase is independently re-runnable. Skip phases that already exist. ## Key decision points 1. **MCU selection** — ESP32-C3 (BLE+WiFi, RISC-V, cheap) vs ESP32-S3 (AI, USB) vs STM32 (low power) vs nRF (BLE-only) 2. **HV topology** — if product needs high voltage (mosquito swatter, taser), see [references/hv-design.md](references/hv-design.md) 3. **PCB form factor** — match physical product shape, not default rectangle 4. **App framework** — UniApp (WeChat+Android+iOS) vs React Native vs Flutter ## Companion skills - **[operating-kicad-eda](../operating-kicad-eda/SKILL.md)** — Phase 3 detail, KiCad MCP tool routing - **developing-software** — firmware language pattern...