: Embedded prototype: mmWave radar wearable with directional BLE audio alerts

Seeking an embedded systems engineer to build a working prototype of a small wearable device for runners. The device uses mmWave radar with angle-of-arrival estimation to detect objects approaching from behind and sends a directional voice alert ("on your left" / "on your right") to the user's Bluetooth headphones via a minimal companion app (iOS first). Full spec provided to shortlisted candidates after NDA. Highlights: single-module AoA radar (TI IWR-class or similar), nRF52-class BLE MCU, 3+ hr battery, USB-C, target size ~40×30×12mm (larger acceptable for v1). Deliverables: 2 prototype units, firmware source, minimal companion app, tuning documentation. Acceptance criteria are defined and measurable; expect 2–3 field-tuning iterations against my test logs. To be considered, answer these in your proposal: Estimated total hours, broken out by phase (design / prototype build / field tuning) Your experience with mmWave angle-of-arrival radar (TI IWR series or similar) — link examples Recommended approach for the phone-app audio relay Realistic size you can hit in a first prototype. Proposals that don't answer all four questions will not be reviewed. All IP and source code assigned to client. Weekly hour cap will be set in contract.