General Project Context

• We’re building a local-first smart HVAC system that integrates furnaces, HRVs, temperature/humidity sensors, and more. Your team will help develop a production-ready controller board that communicates with these systems via a central Hub.

Project Brief

• You will design a custom PCB for a smart HVAC controller system, based on the Arduino Nano Matter dev board. The PCB must support power conversion, multi-relay switching, sensor output, memory and Ethernet modules, and fit within an enclosure being designed by another student team.
• This project must be completed in close collaboration with Project B: Smart HVAC Controller Enclosure Design. Your board layout must follow the prescribed physical orientation to align with port cutouts and indicators in the enclosure.

MANDATORY Board Orientation Requirements

• Front of Board (facing user):
• 1x Button (connected to D5, with resistor)
• 4x LEDs (Green, Blue, Yellow, Red) – aligned in a row
• 1x USB-C port (for Arduino Nano Matter access)
• Back of Board (wiring side):
• 2x Terminal Blocks for AC power input:
• 24V AC Power
• 24V AC Common
• 4x 24V AC relay outputs (Normally Open)
• 3x Double Terminal Blocks for slave outputs (5V DC):
• Power OUT 1, 2, 3
• Common OUT 1, 2, 3
• 1x Ethernet RJ-45 port
• Sides:
• Left and Right remain blank
• The component placement must match this layout, as it defines the enclosure port positions.

Additional Technical Requirements

• Use Arduino Nano Matter or compatible chipset (3.3V logic)
• Convert 24VAC input to 3.3V DC (or 5V via VIN if needed)
• Use ENC28J60 Ethernet module (SPI pins: D10–D13; powered at 3.3V)
• Add 256MB memory chip via I²C (SDA = A4, SCL = A5)
• Relays triggered via:
• A0 → Green LED
• A1 → Blue LED
• A2 → Yellow LED
• A3 → Red LED
• Emphasize magnetic mounting support, compact layout, and EMC resilience

Deliverables

• PCB schematic + layout (KiCad or equivalent)
• Gerber files
• Fully labeled board orientation diagram
• Component list (BOM) with supplier recommendations
• Assembly + testing documentation
• Testing report: power efficiency, relay switching, safety (over-voltage, shorts)

Student Learning Outcomes

• Advanced PCB design under real constraints
• Power conversion and HVAC switching logic
• Working with embedded protocols and external memory
• Cross-disciplinary collaboration with mechanical design team
• Designing for manufacturability and HVAC installation