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 is the difference between MQTT MQTT-SN and CoAP protocols for IoT? Answer MQTT (MQ Telemetry Transport): TCP-based pub/sub protocol. Excellent for reliable always-connected devices. Overhead ~2 bytes header. Best for: gateways cloud-connected sensors. QoS 0 (at most once)…
Q: How to measure and optimize embedded Linux power consumption? Answer Power measurement: use a precision shunt resistor (1-10 mOhm) + oscilloscope with current probe or a bench power supply with current measurement. Software tools: powertop shows per-process power draw.…
Q: What are the security hardening steps for production embedded Linux devices? Answer Hardening steps: (1) Disable unused services (systemctl disable ). (2) Use AppArmor or SELinux to confine applications. (3) Remove SUID binaries where unnecessary. (4) Enable ASLR: CONFIG_ARCH_HAS_RANDOMIZE_BASE=y.…
Q: How to cross-compile Linux applications and kernel for embedded ARM targets? Answer Use a cross-compiler: for ARM64 (aarch64): aarch64-linux-gnu-gcc; for ARM32 (armv7): arm-linux-gnueabihf-gcc. Set CROSS_COMPILE=… and ARCH=arm64 in make commands. Build kernel: make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- defconfig then make ARCH=arm64…
Q: How to implement persistent storage with overlayroot and UBIFS on NAND flash? Answer For NAND-based systems (IoT gateways industrial controllers): use UBIFS on top of UBI (Unsorted Block Images) for wear-leveling and bad block management. Create: ubiattach /dev/ubi_ctrl -m…
Q: How to use Device Tree (DTS) overlays for configuring hardware on embedded Linux? Answer Device Tree overlays (.dtbo) dynamically modify the base .dtb to enable/configure hardware without rebuilding the kernel. Create overlay: write a .dts with a fragment@0 {…
Q: How to boot embedded Linux over the network (NFS root) for development? Answer Network boot eliminates flash writes during development. Configure U-Boot: setenv ipaddr setenv serverip setenv bootargs root=/dev/nfs nfsroot=:/path/to/rootfs rw ip=dhcp. On the host: install nfs-kernel-server export the…