ESP32-S3 Bicycle Race Timer Prototype

# Hardware Development – ESP32-S3 Based Bicycle Race Timer (Prototype PCB)

## Project Overview

We are developing a rugged bicycle race timer based on the ESP32-S3 N16R8 module. The core firmware has already been developed and is running successfully on the development board.

We are looking for an experienced embedded hardware/PCB designer to design a prototype PCB that will allow us to validate the complete hardware before moving to the final production version.

The final product will be mounted on a bicycle and used in rough off-road racing conditions, therefore the design must focus on reliability, waterproofing, vibration resistance, and low power consumption.

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## Scope of Work

The selected freelancer/company will be responsible for:

- Complete schematic design
- PCB layout design
- Component selection (where required)
- Design review
- Prototype-ready PCB
- Manufacturing files
- Mechanical deliverables (STEP model)
- Support during prototype manufacturing if required

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## Hardware Requirements

The prototype PCB should include the following:

- ESP32-S3 N16R8 module
- 4 GB SPI NAND Flash Memory
- u-blox MIA-M10 GNSS/GPS Module
- External GNSS antenna
- GPS status LED
- Battery connector
- Battery charging circuit
- Battery protection circuit
- Power management circuit
- Battery charging indicator
- Power status indicator
- USB Type-C connector for:
- Firmware programming
- Battery charging
- Power ON/OFF switch
- Three waterproof navigation buttons:
- UP
- DOWN
- OK
- Dedicated START button
- RESET button
- BOOT button
- Required voltage regulators
- ESD protection
- Supporting passive components
- Proper decoupling and filtering

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## Display Requirements

The display has not yet been finalized.

We are evaluating multiple display technologies and would appreciate recommendations from the hardware designer.

The PCB should support one of the following:

- SPI Display
- 8-bit Parallel Display
- 16-bit Parallel Display

Preferred display characteristics:

- Outdoor visibility
- Sunlight readable
- Low power consumption
- Fast refresh rate
- Good ESP32-S3 compatibility
- Long-term availability
- Easily obtainable in production quantities

Please recommend the most suitable display and display controller based on the project requirements.

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## PCB Requirements

The PCB should include:

- USB Type-C programming interface
- USB Type-C charging support
- Battery connector
- GPS interface
- SPI NAND interface
- Display interface
- Status LEDs
- UART programming/debug interface
- Test points for:
- 3.3V
- VBAT
- GND
- UART
- Proper RF layout for GPS and BLE
- Proper antenna placement
- Reserved GPIOs for future expansion wherever possible
- Design optimized for manufacturing

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## Firmware Status

The firmware is already under development and running on the development board.

The prototype PCB will be used to validate:

- Hardware integration
- Firmware integration
- GPS performance
- BLE communication
- Display integration
- Battery charging
- Power management
- Overall system stability

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## Mechanical & Environmental Requirements

The final product will be used in demanding outdoor environments.

The design should withstand:

- Continuous vibration
- Heavy shocks
- Rough terrain
- Rain
- Mud
- Dust
- Direct sunlight
- High ambient temperatures
- Water exposure

Target enclosure rating:

IP67 or better

The PCB should be designed considering:

- Waterproof enclosure
- Waterproof buttons
- GPS antenna isolation
- BLE antenna keep-out area
- Efficient thermal management
- Ease of assembly
- Production readiness

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## User Interface

The device will include:

- Display
- START button
- UP button
- DOWN button
- OK button

Navigation buttons will be used for:

- Menu navigation
- Track selection
- BLE device management
- System settings

The START button will be dedicated exclusively to race operation.

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## Future Expansion

The design should allow future support for:

- BLE communication
- OTA firmware updates
- Track management
- GPS lap timing
- Additional sensors
- Future peripherals using available GPIOs

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## Deliverables

The final deliverables should include:

- Complete schematic
- PCB layout files
- Gerber files
- BOM (Bill of Materials)
- Pick & Place files
- Manufacturing-ready package
- Design review notes
- PCB fabrication recommendations
- Assembly recommendations

### Mechanical Deliverables

- Complete 3D PCB STEP model
- Component placement verification
- Mechanical clearance verification
- Display placement verification
- Button placement verification
- USB Type-C accessibility verification
- GPS antenna placement recommendations
- Mounting hole locations
- Enclosure alignment support for future waterproof enclosure development

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## Preferred Experience

Applicants with experience in the following areas will be preferred:

- ESP32 hardware design
- RF layout (BLE/GPS)
- GNSS modules (u-blox)
- USB Type-C power and charging circuits
- Battery-powered embedded devices
- Waterproof product design
- Outdoor electronics
- Low-power embedded systems
- Production-ready PCB design

Please include examples of similar embedded hardware or PCB projects that you have completed.