5634

Imagine upgrading any room's switchboard or air conditioner to become a fully intelligent, Matter-compliant, smart home device—without replacing appliances or touching a cloud server. That’s exactly what Relio sets out to achieve.

Relio is a compact and powerful smart control unit designed to bring modern connectivity and automation into legacy spaces. From IR-controlled air conditioners to traditional wall switch panels, Relio serves as a drop-in upgrade. At its core is the Beetle ESP32-C6, a Wi-Fi and Thread-capable RISC-V SoC, connected to a suite of sensors and controllers to manage power, monitor air quality, detect occupancy, and even learn IR commands.

The Idea Behind Relio

As smart home ecosystems evolve, the Matter protocol is emerging as a universal standard. But the real challenge lies in bridging the gap between this new standard and existing non-smart infrastructure. Whether you're in a rented apartment, a hotel room, or a commercial space—rewiring is often not an option. That’s where Relio comes in: it retrofits intelligence onto your existing appliances, switchboards, or room ACs without altering the electrical setup.

Core Hardware Architecture

The design is centered around the Beetle ESP32-C6, a compact development board from DFRobot featuring Espressif’s RISC-V based ESP32-C6 chip. This SoC supports both Wi-Fi and Thread, making it ideal for local Matter-based communication. Its minimal power consumption and GPIO availability make it well-suited for embedded control applications like this.
 
Relio v1.0: Block Diagram

Sensors

Relio features two key sensors:
 
  • HLK-LD2420 mmWave Radar: Used for precise human presence detection, this sensor offers better accuracy than PIR sensors, especially for detecting stationary occupants.
     
  • Bosch BME688: This AI-capable environmental sensor goes beyond typical temperature, humidity, and pressure measurements. With trained AI models, it can detect VOC levels and estimate CO₂ equivalents—triggering actions based on air quality events like cooking, pollution, or human presence.

Power Monitoring and Relay Control

To provide energy awareness and control over connected devices:
 
  • BL0942 Energy Metering IC is employed to track real-time power consumption per relay channel.
     
  • Three high-current relays (5A+) allow switching of AC appliances like lights, fans, heaters, or plug-in ACs. Each relay is protected and isolated for safe operation, where each channel is cleanly laid out with snubbers and opto-isolated drive circuitry.

IR Control Capabilities

One of Relio's standout features is its infrared learning and transmission system. An onboard IR receiver captures commands from any remote-controlled appliance, while the IR transmitter can replay them on demand. This allows smart control of legacy appliances—like air conditioners or TVs—via Matter or Home Assistant routines.

Compact Schematic with Maximum Integration

As seen in the schematic, the circuit integrates power supply regulation, communication interfaces (UART, I2C), and relay switching with proper spacing and safety measures. Each subsystem is modularly laid out for troubleshooting and assembly. The design makes full use of the Beetle ESP32-C6's IO without overwhelming the board footprint, showcasing a thoughtful balance between functionality and manufacturability.

Fabrication by NextPCB

The fabrication and assembly of the Relio prototype were expertly handled and sponsored by NextPCB, whose team demonstrated remarkable attention to detail throughout the entire manufacturing process. From the very beginning, they were deeply involved—conducting thorough DFM (Design for Manufacturing) checks and providing valuable feedback that ensured the design would be both manufacturable and robust. What truly stood out was their proactive communication: NextPCB's engineers took the time to ask clarifying questions wherever needed, ensuring that no aspect of the project was overlooked or misinterpreted. This level of engagement helped avoid errors, streamlined the SMT assembly process, and ultimately ensured that the boards were assembled to exact specifications. Their transparent workflow, regular progress updates, and fast turnaround meant that the fully populated and tested PCBs were delivered quickly, allowing firmware development to begin without delays.
 
Snapshot of Relio v1.0 during final production checks.

Current Development and Plans

The firmware for Relio is currently under active development and testing. At this stage, testing is focused on core features such as relay control, presence detection, environmental sensing, and IR learning and transmission. Looking ahead, the roadmap includes over-the-air (OTA) firmware updates, enabling future enhancements without physical intervention. There are also plans to fully integrate Relio with Home Assistant , providing users with broad platform compatibility. Once these stages are complete, the codebase and hardware files will be published on GitHub.

Use Cases and Applications

The goal of this project is to create a simple retrofit module that can be added to existing switchboards, wall sockets, or AC units. It’s intended for scenarios where full rewiring or replacing devices isn’t practical. For example, in a typical room setup, the module can be mounted behind a switch panel or near an appliance, where it can control devices via relays or IR, while also monitoring occupancy and environment. This setup can help automate lights or ACs based on presence, or trigger alerts when air quality drops. The addition of power monitoring allows for tracking energy usage. Since everything works over Matter with local communication, it integrates well with local automation systems like Home Assistant, without relying on cloud services.