I started with the hardware-to-cloud pipeline which felt right, but I kept second-guessing whether they wanted me to go deep on the Bluetooth mesh piece or just treat devices as black boxes.
Start by clarifying requirements and scale (e.g., number of devices, update frequency, accuracy). Then design the end-to-end flow: device-to-phone communication, crowd-sourced location reporting, and backend services for storage and query. Finally, discuss trade-offs around privacy, battery life, and consistency.
Pro tip: Emphasize privacy and battery constraints early, as they drive architectural decisions like using Bluetooth Low Energy and end-to-end encryption. Show awareness of Amazon's scale by discussing partitioning and fault tolerance.
Ask about scale (millions of devices), update frequency, accuracy needs, battery life, and privacy requirements. Define functional and non-functional requirements.
Outline the main components: AirTag-like device, finder devices (phones), backend services, and user apps. Describe the crowd-sourced network and communication protocols (BLE, UWB).
Explain how the tag broadcasts BLE signals, how finder devices detect and report location anonymously, and how the backend processes and stores these updates.
Design the backend for ingesting location reports, storing them (e.g., in a time-series or geospatial database), and serving queries to the owner. Discuss partitioning, replication, and consistency.
Discuss trade-offs: privacy vs. utility, battery vs. update frequency, consistency vs. availability. Mention optimizations like batching, caching, and edge processing.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.