8. Modules & Extensions

SMHUB is designed to be modular. The main board provides essential radios, networking, and I/O, while additional hardware modules extend functionality for power resilience, connectivity, and advanced integrations. 

 

 8.1 USB Passthrough 

 

 

 Purpose: Enables SMHUB to act either as a USB host (powering connected peripherals) or as a USB device (connected to a PC or another host). 

 

 

 Logic: 

 

 Automatically decides whether to supply or draw power. 

 

 Prevents reverse powering through integrated FET switching. 

 

 

 

 

 Use Cases: 

 

 

 Attach Z-Wave or extra Zigbee dongles, printers, audio devices, storage etc. 

 

 

 Connect SMHUB to a PC for development/debugging. 

 

 

 Power downstream devices safely. 

 

 

 

 

 

 8.2 SD Card 

 

 

 Slot: Standard microSD slot on the main board. 

 

 

 Purpose: Expand storage for logs, app data, or backups. 

 

 

 Integration: 

 

 

 Mounted automatically by the Linux OS. 

 

 Users can format, mount/unmount, and monitor usage from the UI. 

 Support up to 2Tb volume. 

 

 

 

 

 8.3 PoE Module 

 

 

 Standard: IEEE 802.3af-compliant. 

 

 

 Input: Power delivered via Ethernet cable from a PoE-enabled switch or injector. 

 

 

 Output: Stable 5V regulated supply to the hub. 

 

 

 Protection: Surge and ESD protection integrated. 

 

 

 Monitoring: “PoE Power Check” exposed in the system for telemetry. 

 

 

 Use Case: Ideal for enterprise deployments where powering over Ethernet is standard. 

 

 

 

 8.4 UPS Module 

 

 

 Battery: Supports 18650 Li-ion cells (user-installed). 

 

 

 Charger: advanced circuit with overcharge/undervoltage protection. 

 

 

 Conversion: Step-up/step-down converters to maintain 5V, 3.3V, 1.8V rails. 

 

 

 Telemetry: 

 

 

 Monitors voltage/current 

 

 

 Provides battery health and charge state in the UI. 

 

 

 

 

 Inputs: Can also accept DC power or solar panels , making SMHUB deployable off-grid. 

 

 

 Use Case: Ensures uninterrupted operation during outages. 

 

 

 

 8.5 4G/LTE Module 

 

 Connectivity: LTE Cat 1 with fallback modes. 

 

 Interfaces: 

 

 

 Main UART. 

 

 

 USB. 

 

 

 Debug UART. 

 

 

 

 

 SIM Slot: NanoSIM with detection circuitry. 

 

 

 Antennas: Dedicated connectors for LTE and GNSS. 

 

 

 UI Integration: 

 

 

 Settings → Radios → 4G/LTE. 

 

 

 SIM/APN configuration, LTE signal telemetry. 

 

 

 

 

 Status: Hardware available, software support in development . 

 

 

 

 8.6 DIY Pinouts & Interfaces 

 For advanced users and developers, SMHUB exposes additional hardware interfaces: 

 

 

 GPIO pins for general use. 

 

 

 UART, SPI, and I²C buses. 

 

 

 Custom module connectors for prototyping or specialized hardware. 

 

 

 Use Case: Attach sensors, control boards, or experimental expansions not covered by official modules. 

 

 

 

 8.7 Integrated Peripherals 

 While not separate modules, the following are considered part of SMHUB’s extension capabilities: 

 

 

 IR Transmitter & Receiver 

 

 

 Control TVs, AC units, and IR-based devices. 

 

 

 Capture IR codes for learning mode. 

 

 

 

 

 Audio Output (3.5 mm) 

 

 

 System alerts and future media/streaming support. 

 

 

 

 

 Buzzer 

 

 

 Local audible notifications. 

 

 

 

 

 LED Systems 

 

 

 12 WS2812B RGB LEDs (Ambilight) – running by default, user configurable. 

 

 

 4 Service LEDs – network, power, radio status.