Q: How to implement watchdog and self-healing mechanisms for always-on IoT devices? Answer Multi-level watchdog strategy: (1) Hardware watchdog: STM32 independent watchdog (IWDG) – resets MCU if software hangs. Configure timeout < worst-case loop time. (2) Software watchdog: external process…
Q: How to design MQTT topic hierarchies and payload formats for large-scale IoT deployments? Answer MQTT topic hierarchy best practices: Example: factory1 Use wildcards (# + single-level) for subscriptions. Payload format: use JSON for human readability; Protocol Buffers (protobuf)…
Q: What is the role of edge computing in IoT and how to implement it effectively? Answer Edge computing in IoT addresses: latency cloud cost bandwidth privacy and reliability. Use cases: (1) Real-time control loops (
Q: How to implement time-series data storage and analytics for IoT sensor data? Answer For IoT time-series storage: (1) InfluxDB: purpose-built time-series DB with InfluxQL and Flux query languages. Built-in retention policies downsampling and continuous queries. Native Telegraf collectors for…
Q: What are the challenges of LPWAN technologies (LoRaWAN Sigfox NB-IoT) and how to choose? Answer LPWAN comparison: LoRaWAN: unlicensed sub-GHz ISM band 0.3-50 kbps range 2-10 km urban 10+ km rural. Best for: agricultural sensor networks DIY projects. License-free…
Q: How to implement secure remote access to IoT devices behind NAT for maintenance? Answer Options for remote IoT access: (1) MQTT reverse tunnel: persistent MQTT connection from device to cloud broker – cloud initiates via topic-based commands. (2) SSH…
Q: What industrial IoT protocols are most important and how do they compare? Answer Key industrial IoT protocols: (1) MQTT: lightweight pub/sub 2-byte header widely used for cloud integration. (2) OPC-UA: full-featured industrial interoperability protocol with information modeling built-in security.…
Q: How to design an IoT gateway architecture for edge computing and cloud synchronization? Answer Edge computing IoT gateway architecture layers: (1) Data acquisition layer: protocol drivers (Modbus OPC-UA BACnet) running as microservices. (2) Edge processing layer: time-series database (InfluxDB…
Q: What are the key considerations for IoT OTA firmware update design and implementation? Answer IoT OTA update design must address: (1) Atomic update: use A/B partitions so update failure never bricks the device. (2) Delta updates: send only the…
Q: How to integrate multiple sensor types into an IoT gateway using industrial protocols? Answer Industrial IoT gateways typically aggregate: (1) Modbus RTU (RS-485): poll registers from PLCs and sensors at configurable intervals. (2) Modbus TCP: for Ethernet-connected PLCs. (3)…