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)…
Q: What are the best practices for low-power IoT device design to achieve multi-year battery life? Answer Achieving multi-year battery life requires aggressive power management: (1) Choose the right sleep mode: Hibernate ( Stop (1-5 uA) > Sleep (100-200 uA).…
Q: How to implement end-to-end TLS security for IoT devices with certificate authentication? Answer For embedded TLS on IoT devices: (1) Use TLS 1.2 minimum – TLS 1.3 is preferred for lower latency. (2) Use mbedTLS or wolfSSL for embedded…
Q: What are the differences between radiated and conducted emissions testing and how to prepare for each? Answer Radiated vs conducted emissions: Conducted emissions (150 kHz-30 MHz): measured on power lines using LISN (Line Impedance Stabilization Network). Source: switching noise…
Q: How to implement EMC mitigation for IoT devices in industrial environments (EMC immunity)? Answer Industrial EMC immunity requirements (IEC 61000-4 series): (1) ESD immunity (61000-4-2): add TVS diodes on all external connectors. (2) Radiated RF immunity (61000-4-3): 10 V/m…
Q: What are the EMC considerations for wireless module integration (BLE WiFi LoRa)? Answer Wireless module EMC integration: (1) Antenna placement: keep antenna at the board edge or corner. Keep RF trace from module to antenna as short as possible…