An ultra-low-power, modular IoT motion detection unit based on a CubeCell (LoRa) and PIR sensor, designed for smart home systems to provide long-range wireless alerts and multi-year battery life in a compact, low-cost PCB.
This project presents a compact, low-power IoT movement recognition module designed as a modular building block for future smart home systems. The unit detects human motion using a PIR sensor and processes events with a CubeCell HTCC-AM02 microcontroller, which integrates a LoRa transceiver to enable long-range, low-energy wireless communication. A custom PCB (3.4 × 6 cm) was designed and manufactured, integrating the sensing, processing, and power-management subsystems in a small and cost-effective form factor.
The power architecture includes a rechargeable Li-ion battery, USB-C charging, a BQ24072 power-path charger, a buck-boost DC-DC converter for the PIR supply, and a low-noise LDO for the 3.3 V logic rail. To maximize battery lifetime, the system operates mainly in deep-sleep mode, drawing only a few microamps, and wakes up via an interrupt from the PIR sensor or a periodic timer. Upon motion detection, the device measures the battery voltage, transmits a LoRa message to the main home unit or user, and then returns to low-power sleep.
The design focuses on modularity, affordability, and sustainability: each unit can function independently, be easily added to a larger smart-home network, and operate for years on a single charge. The project covers the full development cycle, including component selection, schematic and PCB design, firmware implementation in Arduino, power optimization, and laboratory validation, demonstrating a complete, reliable, and scalable IoT sensing solution.
