# 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 1. ESP32-S3 compute and user-interface board. 2. Battery charging, gauging, power-path, and switched-rail subsystem. 3. Display, keyboard/buttons, haptic motor, and buzzer. 4. microSD and USB-C subsystem. 5. NFC module and antenna. 6. Region-specific sub-GHz transceiver module and antenna connector. 7. Infrared transmitter/receiver. 8. Protected multi-voltage hardware-debug interface. 9. 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.