This repository contains a complete KiCad project for a Four Relay Module designed for various control applications. The PCB design allows for controlling up to four independent relays, making it ideal for home automation, industrial control systems, IoT projects, or any application requiring switched power control.
- 4-Channel Relay Control: Independent control of four separate relay channels
- Opto-Isolated Design: Safe isolation between the control circuitry and relay switching
- Power Options: Compatible with 5V or 12V power supply (depending on relay specifications)
- LED Indicators: Status LEDs for each relay channel
- Compact Design: Efficient layout with optimized component placement
- Screw Terminal Blocks: Easy connection for input/output wiring
- Mounting Holes: Standard mounting hole pattern for easy installation
The Four Relay Module schematic includes:
- Input Stage: Opto-isolators to protect the control circuitry
- Driver Stage: Transistor-based relay drivers with flyback diodes
- Power Regulation: Voltage regulation circuitry if needed for specific relay coil voltages
- I/O Connectors: Headers for control signals and screw terminals for relay contacts
The PCB is designed as a 2-layer board with the following specifications:
- Dimensions: 65*75 mm
- Copper Weight: copper for standard current handling
- Trace Width: 2.5mm , 1 mm , 0.8 mm , 0.5 mm respectively sized for relay current requirements
- Ground Plane: Full ground plane for noise reduction and thermal management
- Silkscreen: component labeling and polarity indicators
- Component Spacing: Optimized for manual assembly and adequate cooling
- KiCad 9.0 or later
- Standard soldering equipment
- Electronic components as listed in the BOM
The design includes all necessary manufacturing outputs:
- Gerber files for PCB fabrication can be generated from the KiCad project as per requirements
- Drill files for hole placement
- Pick-and-place files for automated assembly (if applicable)
- BOM (Bill of Materials) for component sourcing
- Order PCBs from your preferred PCB manufacturer using the provided Gerber files
- Source components according to the BOM
- Assemble the PCB following standard soldering practices
- Test functionality before deployment
- Connect power supply to the designated power input terminals (5V/12V as per your relay specification)
- Connect control signals to the input pins (typically active LOW)
- Connect the load devices to the relay output terminals (NO/NC/COM)
- Apply control signals to activate/deactivate relays as needed
RelayModulePCBDesign/
│
├── RelayModulePCBDesign.kicad_pro # KiCad project file
├── RelayModulePCBDesign.kicad_sch # Schematic file
├── RelayModulePCBDesign.kicad_pcb # PCB design file
├── RelayModulePCBDesign.kicad_prl # Project library file
│
├── bom/ # Bill of Materials
│ └── ibom.html # Interactive BOM
│
├── .gitignore # Git ignore file
└── README.md # This file
The project includes an interactive HTML BOM (bom/ibom.html) which you can open in any web browser to help with assembly. This provides:
- Visual component placement guide
- Component references and values
- Interactive highlighting of components
- Filtering by component type or value
- Current Handling: The PCB traces are designed to handle the rated current of the relays
- Thermal Management: Component spacing allows for adequate heat dissipation
- EMI/EMC: Layout considerations to minimize electromagnetic interference
- Safety: Appropriate clearance and creepage distances for voltage isolation
This project is licensed under the MIT License - see the LICENSE file for details.
- KiCad EDA Suite for the design tools
- KiCad Libraries for component symbols and footprints
Contributions to improve the design are welcome. Please feel free to fork the repository and submit pull requests.
- Fork the Project
- Create your Feature Branch (
git checkout -b feature/..) - Commit your Changes (
git commit -m 'Add some Feature') - Push to the Branch (
git push origin feature/..) - Open a Pull Request