Responder NAV Field Computer

Responder Nav v0.73 Beta is an expandable, offline-capable field computer for the M5Stack Tab5. It brings navigation, off-grid communications, radio utilities, vehicle diagnostics, local file transfer, and practical field tools into one landscape terminal interface.

Beta software: test critical workflows before relying on them. Responder NAV is not emergency, life-safety, aviation, or professional vehicle-diagnostic equipment.

What changed in v0.73 Beta

• Prevents the active RF/USB app from reclaiming USB while Wi-Fi is being restored.
• Keeps the Wi-Fi restoration screen active until the device is actually reconnected.
• Stops Deploy Cam cleanly before low-memory Wi-Fi recovery can invalidate its live socket.
• Holds the Tab5 backlight off through managed BLE resets to hide the controller's default blue frame.
• Refines RF Scan, MeshCore, Car Scanner, and File Manager layouts and targeted redraws.
• Protects active map tiles from neighboring-zoom cache eviction and backs off cleanly when the map framebuffer is temporarily busy.
• Validates four-direction map panning, key-release behavior, recenter, and zoom transitions on Tab5 hardware.

Design philosophy

Responder NAV is built around four ideas:

• Offline first
• Expandable by design
• Practical field utilities
• A focused, purpose-built user experience

It is not intended to replace a smartphone, laptop, certified scanner, or SDR workstation. The goal is a responsive field device that can continue to provide useful local tools when Internet service is unavailable.

Photos

Current features

Navigation and field utilities

• GPS map navigation, manual panning, saved locations, and trip logging
• Weather, calendar, notes, gallery, audio recorder, and system health
• Token-protected local SD-card file transfer from a browser
• Custom lock screen and terminal-style UI

Communications

• MeshCore-compatible LoRa messaging, position sharing, telemetry, and selectable radio presets
• BLE keyboard mode
• Wi-Fi configuration and reconnect handling

RF and diagnostics

• RTL2832U/R820T2 RTL-SDR support, FM reception, RF scanning, Ghost Box, TPMS monitoring, and aircraft utilities
• USB ELM327 OBD-II diagnostics
• Optional Freenove ESP32-WROVER Deploy Cam companion firmware

Wi-Fi Motion and Wasteland Responder are intentionally excluded from v0.73 Beta. Hardware-dependent features vary with the exact module, USB adapter, antenna, hub, vehicle, region, and radio environment.

Hardware

Core hardware:

• M5Stack Tab5 and Tab5 keyboard
• microSD card
• M5Stack Module GPS V2.0 w/ External Antenna (AT6668)
• M5Stack U184-US915 LORAWAN-US915 module

Optional peripherals:

• RTL2832U/R820T2 RTL-SDR
• USB ELM327 adapter
• Freenove FNK0060/FNK0060B ESP32-WROVER camera

See HARDWARE.md for connection and compatibility notes.

Build

1. Install VS Code with PlatformIO or PioArduino.
2. Clone this repository.
3. Open the repository root.
4. Build esp32p4_pioarduino55.

pio run -e esp32p4_pioarduino55

Detailed setup is in BUILDING.md. Prebuilt image usage is in FLASHING.md.

First start

1. Format a microSD card as FAT32 or exFAT.
2. Copy sdcard/ to the card root.
3. Insert the card and boot the Tab5.
4. Open Utilities > API Keys and enter your own Thunderforest map key.
5. Open Utilities > Wi-Fi and configure your own network.

The release contains no personal SSID, Wi-Fi password, API key, private MeshCore network, location history, or development font. Credentials entered on the device are stored locally in preferences; the standard public image does not enable flash encryption.

Optional apps

The v0.73 package system reads /apps/<package>/app.json manifests from the SD card to expose optional modules already compiled into the firmware. It does not load arbitrary native binaries from SD.

See APP_DEVELOPMENT.md and docs/external_app_packages.md.

File transfer

Open File Transfer on the Tab5 and enter the complete protected URL shown on its screen from another device on the same trusted network. The web UI can browse folders, upload, download, create folders, and delete files. Closing the app stops the server and invalidates the session token.

The connection uses plain HTTP rather than TLS. Do not expose port 8080 to the Internet.

Repository layout

• src/ — Tab5 firmware
• include/responder/ — application and service interfaces
• lib/ — project-local hardware libraries
• partitions/ — Tab5 partition layout
• sdcard/ — public-safe starter SD-card tree
• apps/ — optional v0.73 Beta app manifests ready to copy to SD
• examples/ — app package examples
• deploy_cam_esp32cam/ — companion camera firmware
• firmware/ — versioned release images and checksums
• tools/ — serial regression helpers

Development and attribution

Responder NAV was designed by Alberto Cajiao Hernandez / ACH Industries. Its hardware architecture, product direction, feature set, and user experience were developed through hands-on embedded prototyping, with OpenAI Codex used as an AI-assisted implementation, debugging, refactoring, and documentation tool.

M5Stack, OpenAI, Codex, MeshCore, ESP-IDF, RTL-SDR, and other referenced names are trademarks or projects of their respective owners. Their mention describes compatibility or tooling and does not imply sponsorship or endorsement.

Security, safety, and responsible use

• Read SECURITY.md before enabling local web services.
• Remove credentials and precise locations from shared serial logs.
• Follow local radio, privacy, aviation, traffic, and vehicle-access laws.
• Do not operate the interface while driving; have a passenger use it or stop safely.
• Do not use decoded radio or vehicle data as the sole basis for a safety-critical decision.

Contributing

Bug reports should include the firmware version, hardware model, connection method, reproduction steps, and a sanitized 115200-baud serial log. See CONTRIBUTING.md.

License

Unless marked otherwise, original Responder NAV source, documentation, and UI assets are licensed under GPL-3.0-or-later; see LICENSE. If you distribute a firmware binary, provide the corresponding source used to build it through an equally accessible location. Bundled components retain their own compatible licenses and notices in THIRD_PARTY_NOTICES.md.

This software is provided without warranty. See LEGAL.md for the practical release and trademark notes.