Project Specification
Product Vision
A modular, battery-powered field toolkit for authorized hardware and wireless security research. The product will begin as an accessible proof-of-concept platform and later be reduced into a sealed, weather-resistant handheld.
Intended Use and Safety Boundary
- Authorized testing, device development, diagnostics, protocol analysis, and laboratory/field research only.
- Firmware should include clear transmit controls, regional radio configuration, and safeguards against accidental continuous transmission.
- The design must not assume permission to access, interfere with, or impersonate third-party systems.
Development Strategy
Phase 1 — Modular Proof of Concept
Build a larger, serviceable platform that validates the architecture and interfaces. Use modules and accessible headers where practical so failures and substitutions are easy to diagnose.
Phase 2 — Integrated Handheld
Consolidate validated functions onto a smaller PCB, optimize standby power and RF coexistence, and develop a sealed enclosure with protected external interfaces.
Phase 1 Functional Requirements
Processing and User Interface
- ESP32-S3-class primary controller with Wi-Fi and BLE for development, connectivity, and user-interface tasks.
- Color display readable outdoors.
- Physical keyboard or directional controls plus dedicated power and back controls.
- microSD storage for firmware, logs, captures, and configuration.
- USB-C for charging, firmware updates, serial console, and USB device/host experiments where supported.
- Audible and haptic feedback as optional populated features.
Radio and Optical Interfaces
- 13.56 MHz NFC/RFID reader/writer module for authorized tag and protocol development.
- Sub-GHz transceiver module covering permitted regional ISM bands, with replaceable or region-specific RF sections preferred for the prototype.
- Infrared transmit and receive.
- Wi-Fi and BLE through the primary controller.
- RF sections must have independent power gating and clearly defined antenna keepouts.
Wired Hardware Debugging
- Protected UART, I2C, SPI, and general-purpose GPIO interface.
- Selectable target logic voltage, initially 1.8 V, 3.3 V, and 5 V where technically appropriate.
- Input protection, current limiting, and clear pin labeling.
- Target power output must be switchable and current-limited; it must default off.
- Optional SWD/JTAG support through a dedicated debug header or adapter module.
Expansion
- Internal expansion connector exposing regulated power and digital buses.
- External module connector designed so radio or debug boards can be replaced without redesigning the core platform.
- Test points for all power rails and major buses.
Power Requirements
- Rechargeable single-cell Li-ion/LiPo battery architecture for the prototype.
- USB-C charging with battery protection, fuel gauging, thermal monitoring, and load sharing/power-path management.
- Independent load switches for display, radios, SD card, sensors, and expansion modules.
- Deep-sleep operation with wake from buttons, timer, USB, and selected external signals.
- Phase 1 target: one working day of mixed active use and multi-week standby when radios and display are off. Final targets will be refined using measured prototype consumption.
Environmental and Mechanical Requirements
Phase 1
- Serviceable enclosure with splash protection as a goal, not full sealing.
- Conformal-coating compatibility and corrosion-resistant external connectors.
- Operating-temperature goal of at least -10 °C to +50 °C, subject to battery limitations.
Phase 2
- Sealed handheld enclosure targeting IP65 or better.
- Gasketed seams, protected buttons, sealed or capped connectors, pressure equalization as needed, and no exposed microSD slot unless gasketed.
- Outdoor-readable display window and glove-usable controls.
- Battery must remain replaceable by service personnel or be safely retained and thermally managed.
Architecture Constraints
- Prefer certified radio modules during Phase 1 to reduce RF and compliance risk.
- Keep NFC, sub-GHz, Wi-Fi/BLE antennas physically separated and independently disabled.
- Separate noisy power conversion and display signals from RF and NFC antenna regions.
- Use ESD protection on every user-accessible electrical interface.
- Avoid relying on one RF front end to cover incompatible frequency ranges.
Suggested Phase 1 Blocks
- ESP32-S3 compute and user-interface board.
- Battery charging, gauging, power-path, and switched-rail subsystem.
- Display, keyboard/buttons, haptic motor, and buzzer.
- microSD and USB-C subsystem.
- NFC module and antenna.
- Region-specific sub-GHz transceiver module and antenna connector.
- Infrared transmitter/receiver.
- Protected multi-voltage hardware-debug interface.
- Expansion and test connectors.
Validation Criteria for Phase 1
- Boots reliably from battery and USB power.
- Charges safely while operating and reports battery state.
- Demonstrates deep sleep and independently switches off major loads.
- Reads/writes a test microSD card.
- Performs authorized NFC tag read/write tests.
- Performs short-range packet transmit/receive tests in a permitted ISM band.
- Sends and receives infrared test patterns.
- Communicates over UART, I2C, and SPI at each supported logic level without damaging the target or toolkit.
- Logs test results locally and can export them over USB or wireless connectivity.
- Records measured active and standby consumption to guide Phase 2 battery sizing.
Deferred Until After Phase 1
- Final IP-rated enclosure and production sealing process.
- Fully integrated custom RF matching networks and compact shared mechanical antenna system.
- Production certification, emissions testing, and region-specific product variants.
- Aggressive miniaturization, final industrial design, and production cost optimization.
- Final firmware feature set and application/plugin ecosystem.
Immediate Next Step
Create the Phase 1 system block diagram and power budget, then select the core modules and define connector boundaries before schematic capture.