BLE-WiFi/Ethernet Gateway PCB Design
Budget: ₹12,500 – ₹37,500 INR
PCB Design Requirement
Project: BLE to Wi-Fi/Ethernet Gateway Device.
The objective of this project is to design a BLE to Cloud Gateway device that integrates:
- Nordic nRF52840 (BLE receiver)
- HLK7628N Wi-Fi / Ethernet Linux module
The device continuously receives BLE packets, forwards them to the HLK7628N through USB, and uploads the data to the cloud over Wi-Fi or Ethernet.
When internet connectivity is lost, incoming data will be stored locally on an SD card using a rotational buffer mechanism, and synchronized automatically once connectivity is restored.
The design must follow best practices for RF layout, impedance control, EMI mitigation, and grounding, enabling FCC and CE certification.
The HLK7628N module and nRF52840 chip are fixed components and must remain in the design. Other components may be optimized or replaced if required.
2. System Architecture
- Data Flow
BLE Devices
↓
nRF52840 (BLE Receiver)
↓ USB
HLK7628N Linux Module
↓
Wi-Fi / Ethernet
↓
Cloud Server
If internet fails:
BLE → nRF → HLK → SD Card Storage
→ Sync to cloud when internet returns.
3. Core Processing & Communication Components
3.1 nRF52840 SoC
Functions:
- Bluetooth Low Energy 5.x receiver
- Continuous BLE scanning
- USB device interface connected to HLK module
- RF interface for external antenna
Design Requirements:
- Follow Nordic reference design
- Proper RF matching network
- Dedicated clean power supply
- SWD debug interface available
3.2 HLK7628N Module
Functions:
- Wi-Fi connectivity
- Ethernet connectivity
- Linux / OpenWRT environment
- USB host for nRF communication
- SD card storage interface
- LED control via GPIO
Requirements:
- Must follow Hi-Link reference layout
- Ethernet PHY routing compliance
- USB host interface connection to nRF52840
- UART debug header available
4. RF & Antenna Design (Critical for FCC / CE)
- Two independent RF paths must be implemented.
- RF Channels
- Radio Frequency Antenna
- nRF52840 2.4 GHz BLE External antenna
- HLK7628N 2.4 GHz Wi-Fi External antenna
Antenna Requirements
Two external antennas using:
- u.FL / IPEX connectors
Benefits:
- Certification flexibility
- Easier antenna tuning
- RF Matching Network
- Each RF path must include:
- Pi Matching Network
Components:
Inductor
Capacitor
Capacitor
Package Size:
0402 recommended
RF Layout Requirements
The PCB designer must ensure:
50-ohm controlled impedance traces
Short RF traces
Proper RF ground reference
Adequate spacing between antennas
RF isolation from digital circuits
Ground stitching vias must be used around RF sections.
5. Storage System
Micro SD Card Interface
Purpose:
Local storage when internet is unavailable.
Requirements:
Connected to HLK7628N SDIO interface
Micro SD socket type:
Push-push OR push-pull
Recommended:
Industrial grade SD cards
Wear leveling support for rotating logs
6. Power Supply Design
Input Power
USB Type-C connector
5V power input only
USB-C Configuration
CC resistors required for 5V negotiation
No USB data required from USB-C
Power Conversion
Buck Converter
5V → 3.3V
Requirements:
Minimum 1.5A – 2A current capability
High efficiency switching regulator
Used for:
HLK module
Ethernet
peripherals
Low Noise LDO
A dedicated clean 3.3V LDO should power:
nRF52840 RF section
This improves RF stability and noise immunity.
Power Filtering
Include:
Bulk capacitors
Decoupling capacitors per IC
Ferrite beads for RF isolation
Follow reference designs strictly.
7. Ethernet Interface
Ethernet will connect to the HLK module.
Required Components
RJ45 connector with integrated magnetics (preferred)
Benefits:
Simplifies design
Improves EMI performance
Protection Components
Include:
TVS diodes for ESD
Common mode choke if required
Routing must follow Ethernet differential pair rules.
8. USB Interface Between nRF and HLK
Communication between modules will use USB.
Routing Requirements
USB differential pair:
D+
D−
Requirements:
Controlled impedance
Matched length traces
Minimal stubs
Protection
Include:
USB ESD protection IC
9. Debug & Programming Interfaces
HLK7628N
Must include:
UART Debug Header
RX
TX
GND
Also include:
Reset button
Boot mode access if required
nRF52840
Must include:
SWD programming interface:
SWDIO
SWCLK
GND
VCC
RESET
Optional:
USB DFU access
10. Indicators
Two LEDs must be implemented.
LED Function
LED 1 Internet connectivity
LED 2 BLE activity
Each LED must include current limiting resistor.
Controlled by:
HLK GPIO pins
11. Protection & Compliance
The board must include protection for certification readiness.
ESD Protection
Required for:
USB lines
Ethernet port
Antenna connectors (if required)
EMI Suppression
Include:
Ferrite beads
Filtering capacitors
Proper grounding
Grounding Strategy
Recommended:
RF and Digital ground segmentation
Ground stitching vias
Continuous ground plane
12. PCB Design Requirements
PCB Layer Stack
Minimum:
4 Layer PCB
Recommended stack:
Top layer – RF + signals
Ground plane
Power plane
Bottom layer – signals
RF Compliance
PCB designer must ensure:
Controlled impedance traces
RF isolation
Reference layout compliance
Additional Features
Include:
Mounting holes
Proper component spacing
Shielding cans (recommended)
Shielding cans significantly improve chances of passing EMI / FCC tests.
13. Deliverables Expected from Vendor
The PCB designer must provide:
Design Files
Schematic files
PCB layout files
BOM (Bill of Materials)
Gerber files
Pick & place files
Assembly drawings
Design Documentation
Impedance calculation
Stack-up details
RF layout notes
Compliance considerations
Prototype Support
Vendor may be required to assist with:
First prototype debugging
Minor design fixes
Pre-certification review
14. Certification Considerations
The design must consider compliance with:
FCC (USA)
CE (Europe)
The designer must follow:
RF reference layouts
EMI reduction techniques
Ground plane best practices
Use of shielding cans and proper filtering is strongly recommended.
15. Project Deliverables
Vendor must deliver:
Final schematic
PCB layout
BOM
Manufacturing files
Design review support
Prototype revision support
16. Quotation & Timeline Request
Vendors are requested to provide:
Total design cost
Estimated project timeline
Number of design revisions included
Support during prototype bring-up
Experience with RF / FCC compliant designs
17. Future Product Variants
Two additional variants of this device are planned.
These future designs will use:
Same core chipsets
nRF52840
HLK7628N
The vendor selected for this project may be considered for those designs as well.
Project: BLE to Wi-Fi/Ethernet Gateway Device.
The objective of this project is to design a BLE to Cloud Gateway device that integrates:
- Nordic nRF52840 (BLE receiver)
- HLK7628N Wi-Fi / Ethernet Linux module
The device continuously receives BLE packets, forwards them to the HLK7628N through USB, and uploads the data to the cloud over Wi-Fi or Ethernet.
When internet connectivity is lost, incoming data will be stored locally on an SD card using a rotational buffer mechanism, and synchronized automatically once connectivity is restored.
The design must follow best practices for RF layout, impedance control, EMI mitigation, and grounding, enabling FCC and CE certification.
The HLK7628N module and nRF52840 chip are fixed components and must remain in the design. Other components may be optimized or replaced if required.
2. System Architecture
- Data Flow
BLE Devices
↓
nRF52840 (BLE Receiver)
↓ USB
HLK7628N Linux Module
↓
Wi-Fi / Ethernet
↓
Cloud Server
If internet fails:
BLE → nRF → HLK → SD Card Storage
→ Sync to cloud when internet returns.
3. Core Processing & Communication Components
3.1 nRF52840 SoC
Functions:
- Bluetooth Low Energy 5.x receiver
- Continuous BLE scanning
- USB device interface connected to HLK module
- RF interface for external antenna
Design Requirements:
- Follow Nordic reference design
- Proper RF matching network
- Dedicated clean power supply
- SWD debug interface available
3.2 HLK7628N Module
Functions:
- Wi-Fi connectivity
- Ethernet connectivity
- Linux / OpenWRT environment
- USB host for nRF communication
- SD card storage interface
- LED control via GPIO
Requirements:
- Must follow Hi-Link reference layout
- Ethernet PHY routing compliance
- USB host interface connection to nRF52840
- UART debug header available
4. RF & Antenna Design (Critical for FCC / CE)
- Two independent RF paths must be implemented.
- RF Channels
- Radio Frequency Antenna
- nRF52840 2.4 GHz BLE External antenna
- HLK7628N 2.4 GHz Wi-Fi External antenna
Antenna Requirements
Two external antennas using:
- u.FL / IPEX connectors
Benefits:
- Certification flexibility
- Easier antenna tuning
- RF Matching Network
- Each RF path must include:
- Pi Matching Network
Components:
Inductor
Capacitor
Capacitor
Package Size:
0402 recommended
RF Layout Requirements
The PCB designer must ensure:
50-ohm controlled impedance traces
Short RF traces
Proper RF ground reference
Adequate spacing between antennas
RF isolation from digital circuits
Ground stitching vias must be used around RF sections.
5. Storage System
Micro SD Card Interface
Purpose:
Local storage when internet is unavailable.
Requirements:
Connected to HLK7628N SDIO interface
Micro SD socket type:
Push-push OR push-pull
Recommended:
Industrial grade SD cards
Wear leveling support for rotating logs
6. Power Supply Design
Input Power
USB Type-C connector
5V power input only
USB-C Configuration
CC resistors required for 5V negotiation
No USB data required from USB-C
Power Conversion
Buck Converter
5V → 3.3V
Requirements:
Minimum 1.5A – 2A current capability
High efficiency switching regulator
Used for:
HLK module
Ethernet
peripherals
Low Noise LDO
A dedicated clean 3.3V LDO should power:
nRF52840 RF section
This improves RF stability and noise immunity.
Power Filtering
Include:
Bulk capacitors
Decoupling capacitors per IC
Ferrite beads for RF isolation
Follow reference designs strictly.
7. Ethernet Interface
Ethernet will connect to the HLK module.
Required Components
RJ45 connector with integrated magnetics (preferred)
Benefits:
Simplifies design
Improves EMI performance
Protection Components
Include:
TVS diodes for ESD
Common mode choke if required
Routing must follow Ethernet differential pair rules.
8. USB Interface Between nRF and HLK
Communication between modules will use USB.
Routing Requirements
USB differential pair:
D+
D−
Requirements:
Controlled impedance
Matched length traces
Minimal stubs
Protection
Include:
USB ESD protection IC
9. Debug & Programming Interfaces
HLK7628N
Must include:
UART Debug Header
RX
TX
GND
Also include:
Reset button
Boot mode access if required
nRF52840
Must include:
SWD programming interface:
SWDIO
SWCLK
GND
VCC
RESET
Optional:
USB DFU access
10. Indicators
Two LEDs must be implemented.
LED Function
LED 1 Internet connectivity
LED 2 BLE activity
Each LED must include current limiting resistor.
Controlled by:
HLK GPIO pins
11. Protection & Compliance
The board must include protection for certification readiness.
ESD Protection
Required for:
USB lines
Ethernet port
Antenna connectors (if required)
EMI Suppression
Include:
Ferrite beads
Filtering capacitors
Proper grounding
Grounding Strategy
Recommended:
RF and Digital ground segmentation
Ground stitching vias
Continuous ground plane
12. PCB Design Requirements
PCB Layer Stack
Minimum:
4 Layer PCB
Recommended stack:
Top layer – RF + signals
Ground plane
Power plane
Bottom layer – signals
RF Compliance
PCB designer must ensure:
Controlled impedance traces
RF isolation
Reference layout compliance
Additional Features
Include:
Mounting holes
Proper component spacing
Shielding cans (recommended)
Shielding cans significantly improve chances of passing EMI / FCC tests.
13. Deliverables Expected from Vendor
The PCB designer must provide:
Design Files
Schematic files
PCB layout files
BOM (Bill of Materials)
Gerber files
Pick & place files
Assembly drawings
Design Documentation
Impedance calculation
Stack-up details
RF layout notes
Compliance considerations
Prototype Support
Vendor may be required to assist with:
First prototype debugging
Minor design fixes
Pre-certification review
14. Certification Considerations
The design must consider compliance with:
FCC (USA)
CE (Europe)
The designer must follow:
RF reference layouts
EMI reduction techniques
Ground plane best practices
Use of shielding cans and proper filtering is strongly recommended.
15. Project Deliverables
Vendor must deliver:
Final schematic
PCB layout
BOM
Manufacturing files
Design review support
Prototype revision support
16. Quotation & Timeline Request
Vendors are requested to provide:
Total design cost
Estimated project timeline
Number of design revisions included
Support during prototype bring-up
Experience with RF / FCC compliant designs
17. Future Product Variants
Two additional variants of this device are planned.
These future designs will use:
Same core chipsets
nRF52840
HLK7628N
The vendor selected for this project may be considered for those designs as well.