STM32 Hub and Gateway Design
Budget: ₹1,500 – ₹12,500 INR
I need two related STM32 development boards designed for our modular IoT research project. Both boards share the same connector standard but have different capabilities - one acts as a local hub (Board A), and another as a gateway with cellular connectivity (Board B).
Project Overview:
We're building a distributed data acquisition system for environmental monitoring research. Board A collects data from sensors, Board B aggregates data from multiple Board A units and sends to cloud. Think of it like a mesh network with local hubs and a main gateway.
BOARD A - Local Hub (STM32F103)
Core Specifications:
MCU: STM32F103C8T6 (LQFP48)
Crystals: 8MHz main + 32.768kHz RTC
Programming: SWD header + USB-UART (CH340G)
WiFi: ESP32-WROOM-32 module socket
Size: 100mm x 100mm
Connectivity - Four 20-pin IDC Headers:
1x Male header (input from power board)
3x Female headers (for sensor modules)
Standard 20-pin Bus Definition:
Pin 1-2: 24V pass-through
Pin 3-4: 5V system
Pin 5-6: 3.3V system
Pin 7-8: Ground
Pin 9-10: I2C (SDA/SCL)
Pin 11-12: SPI (MOSI/MISO)
Pin 13-14: SPI (SCK/CS)
Pin 15-16: UART2
Pin 17-20: GPIO/ADC
Key Features:
TCA9548A I2C multiplexer (8-channel)
MicroSD card slot (SPI mode)
4x User LEDs + 2x Buttons
USB powered or external 7-24V
Power regulators: 5V/2A, 3.3V/1.5A
Fuse protection on each port
BOARD B - Gateway Controller (STM32H743)
Core Specifications:
MCU: STM32H743VIT6 (LQFP100) - more powerful
Crystals: 25MHz main + 32.768kHz RTC
Programming: SWD + USB-HS with STLink-compatible
RAM: Optional external SDRAM footprint
Size: 120mm x 100mm
Cellular & GPS Integration:
4G Module: SIM7600G-H or EC200U footprint
Standard mini-SIM card slot
External antenna connector (SMA)
Status LEDs for network
GPS: Integrated in SIM7600 or separate NEO-6M
External GPS antenna connector
PPS output for time sync
Power: Separate 4V/2A regulator for cellular
Communication Interfaces:
Same 20-pin IDC x2 for compatibility with Board A
ESP32-WROOM-32 for local WiFi coordination
RS485 transceiver (MAX485) for industrial protocols
Ethernet PHY (LAN8720A) - optional footprint
USB Host capability for 4G dongle alternative
Enhanced Features:
Storage: MicroSD + 8MB SPI Flash (W25Q64)
RTC: External DS3231 with battery backup
Power Monitor: INA219 for current measurement
User Interface:
6x Status LEDs
3x User buttons
Optional I2C OLED header (SSD1306)
Expansion: 40-pin GPIO header for future modules
Power Management:
Input: 9-36V (wider range for field deployment)
Multiple regulators:
5V/3A (system)
3.3V/2A (MCU)
4V/2A (cellular)
3.3V/500mA (GPS)
Backup battery connector (3.7V Li-ion)
Power path management IC
COMMON REQUIREMENTS FOR BOTH BOARDS:
PCB Specifications:
4-layer PCB recommended
2oz copper for power layers
ENIG finish preferred
M3 mounting holes at corners
Clear silkscreen labeling
Protection Features:
ESD protection on all external interfaces
TVS diodes on power inputs
PTC fuses on peripheral ports
Reverse polarity protection
Debug Features:
Test points on major signals
UART debug headers
Power measurement points
Signal LEDs for troubleshooting
Component Selection:
LCSC basic/extended parts preferred
0805 passives for hand soldering
Quality connectors (no cheap clones)
Industrial temperature range where possible
DELIVERABLES (FOR BOTH BOARDS):
Schematics - Complete designs in KiCad/Altium
PCB Layouts - Professional routing with ground planes
Gerber Files - Ready for JLCPCB/PCBWay
3D Models - Visualization of assembled boards
BOM - Complete with LCSC part numbers
Assembly Files - Pick & place data
Documentation - Pinout diagrams, connection guides
Test Code - Basic Arduino/STM32 examples:
Board A: LED blink, WiFi test, I2C scan
Board B: LED blink, SIM status, GPS read
PROJECT NOTES:
This is for a university research project on distributed environmental monitoring. Board A will be deployed at multiple sensor locations (indoor), while Board B will be the central gateway (potentially outdoor in weatherproof enclosure). The boards must be compatible - Board A can connect to Board B using the same 20-pin cables.
We chose different STM32 variants based on processing needs:
F103 is sufficient for sensor data collection
H743 needed for data aggregation and cellular communication
Future Plans: We may later add LoRa modules, but for now, WiFi and cellular are sufficient.
PROPOSAL REQUIREMENTS:
Please include:
Your experience with both STM32F1 and STM32H7 families
Previous cellular integration projects
Approach to handling two related but different designs
Timeline breakdown for both boards
Any cost optimization suggestions
Project Overview:
We're building a distributed data acquisition system for environmental monitoring research. Board A collects data from sensors, Board B aggregates data from multiple Board A units and sends to cloud. Think of it like a mesh network with local hubs and a main gateway.
BOARD A - Local Hub (STM32F103)
Core Specifications:
MCU: STM32F103C8T6 (LQFP48)
Crystals: 8MHz main + 32.768kHz RTC
Programming: SWD header + USB-UART (CH340G)
WiFi: ESP32-WROOM-32 module socket
Size: 100mm x 100mm
Connectivity - Four 20-pin IDC Headers:
1x Male header (input from power board)
3x Female headers (for sensor modules)
Standard 20-pin Bus Definition:
Pin 1-2: 24V pass-through
Pin 3-4: 5V system
Pin 5-6: 3.3V system
Pin 7-8: Ground
Pin 9-10: I2C (SDA/SCL)
Pin 11-12: SPI (MOSI/MISO)
Pin 13-14: SPI (SCK/CS)
Pin 15-16: UART2
Pin 17-20: GPIO/ADC
Key Features:
TCA9548A I2C multiplexer (8-channel)
MicroSD card slot (SPI mode)
4x User LEDs + 2x Buttons
USB powered or external 7-24V
Power regulators: 5V/2A, 3.3V/1.5A
Fuse protection on each port
BOARD B - Gateway Controller (STM32H743)
Core Specifications:
MCU: STM32H743VIT6 (LQFP100) - more powerful
Crystals: 25MHz main + 32.768kHz RTC
Programming: SWD + USB-HS with STLink-compatible
RAM: Optional external SDRAM footprint
Size: 120mm x 100mm
Cellular & GPS Integration:
4G Module: SIM7600G-H or EC200U footprint
Standard mini-SIM card slot
External antenna connector (SMA)
Status LEDs for network
GPS: Integrated in SIM7600 or separate NEO-6M
External GPS antenna connector
PPS output for time sync
Power: Separate 4V/2A regulator for cellular
Communication Interfaces:
Same 20-pin IDC x2 for compatibility with Board A
ESP32-WROOM-32 for local WiFi coordination
RS485 transceiver (MAX485) for industrial protocols
Ethernet PHY (LAN8720A) - optional footprint
USB Host capability for 4G dongle alternative
Enhanced Features:
Storage: MicroSD + 8MB SPI Flash (W25Q64)
RTC: External DS3231 with battery backup
Power Monitor: INA219 for current measurement
User Interface:
6x Status LEDs
3x User buttons
Optional I2C OLED header (SSD1306)
Expansion: 40-pin GPIO header for future modules
Power Management:
Input: 9-36V (wider range for field deployment)
Multiple regulators:
5V/3A (system)
3.3V/2A (MCU)
4V/2A (cellular)
3.3V/500mA (GPS)
Backup battery connector (3.7V Li-ion)
Power path management IC
COMMON REQUIREMENTS FOR BOTH BOARDS:
PCB Specifications:
4-layer PCB recommended
2oz copper for power layers
ENIG finish preferred
M3 mounting holes at corners
Clear silkscreen labeling
Protection Features:
ESD protection on all external interfaces
TVS diodes on power inputs
PTC fuses on peripheral ports
Reverse polarity protection
Debug Features:
Test points on major signals
UART debug headers
Power measurement points
Signal LEDs for troubleshooting
Component Selection:
LCSC basic/extended parts preferred
0805 passives for hand soldering
Quality connectors (no cheap clones)
Industrial temperature range where possible
DELIVERABLES (FOR BOTH BOARDS):
Schematics - Complete designs in KiCad/Altium
PCB Layouts - Professional routing with ground planes
Gerber Files - Ready for JLCPCB/PCBWay
3D Models - Visualization of assembled boards
BOM - Complete with LCSC part numbers
Assembly Files - Pick & place data
Documentation - Pinout diagrams, connection guides
Test Code - Basic Arduino/STM32 examples:
Board A: LED blink, WiFi test, I2C scan
Board B: LED blink, SIM status, GPS read
PROJECT NOTES:
This is for a university research project on distributed environmental monitoring. Board A will be deployed at multiple sensor locations (indoor), while Board B will be the central gateway (potentially outdoor in weatherproof enclosure). The boards must be compatible - Board A can connect to Board B using the same 20-pin cables.
We chose different STM32 variants based on processing needs:
F103 is sufficient for sensor data collection
H743 needed for data aggregation and cellular communication
Future Plans: We may later add LoRa modules, but for now, WiFi and cellular are sufficient.
PROPOSAL REQUIREMENTS:
Please include:
Your experience with both STM32F1 and STM32H7 families
Previous cellular integration projects
Approach to handling two related but different designs
Timeline breakdown for both boards
Any cost optimization suggestions