A FreeRTOS-based ESP32 firmware for a multi-mode digital voice modem hotspot. Designed for amateur radio operators, it currently supports DMR (network→RF transmit), POCSAG, and DAPNET, with a responsive web interface, MQTT integration, WireGuard VPN, SD card database support, and over-the-air firmware updates.
| Channel | Version |
|---|---|
| Stable | 20260301_ESP32 |
| Beta | 20260301_ESP32_BETA |
| Mode | Status | Notes |
|---|---|---|
| DMR | Network→RF TX working. RF→Network RX is work in progress. | |
| POCSAG | ✅ Implemented | RF paging transmitter, queue management, whitelist/blacklist |
| DAPNET | ✅ Implemented | TCP paging network, message history, RIC filtering |
| D-Star | ❌ Not in firmware | Framework stub only |
| YSF (System Fusion) | ❌ Not in firmware | Framework stub only |
| P25 | ❌ Not in firmware | Framework stub only |
| NXDN | ❌ Not in firmware | Framework stub only |
| Function | Pin | Notes |
|---|---|---|
| MMDVM TX | 43 | UART to modem |
| MMDVM RX | 44 | UART from modem |
| MMDVM Boot | 4 | Bootloader trigger |
| MMDVM Reset | 13 | Hard reset |
| OLED SDA | 17 | I2C data |
| OLED SCL | 18 | I2C clock |
| LED | 38 | Status indicator |
| Button | 0 | OLED toggle |
| SD MISO | 9 | SPI |
| SD MOSI | 11 | SPI |
| SD SCLK | 10 | SPI |
| SD CS | 12 | SPI |
| ETH MISO | 47 | W5500 SPI |
| ETH MOSI | 21 | W5500 SPI |
| ETH SCLK | 48 | W5500 SPI |
| ETH CS | 45 | W5500 SPI |
| ETH INT | 14 | W5500 interrupt |
All pins are configurable via the web interface.
| Setting | Default |
|---|---|
| Web username | admin |
| Web password | pi-star |
| WiFi AP SSID | MMDVM-Setup |
| WiFi AP password | mmdvm1234 |
| ArduinoOTA password | mmdvm |
| DMR callsign | N0CALL |
| DMR ID | 1234567 |
- Flash the firmware to your ESP32
- Connect to the
MMDVM-SetupWiFi access point (password:mmdvm1234) - Open a browser and navigate to
http://192.168.4.1 - Log in with
admin/pi-star - Go to Network → WiFi and configure your home WiFi credentials
- Go to Modes → DMR and set your callsign and DMR ID
- Go to Mode Select and enable DMR
- Reboot — the hotspot will connect to BrandMeister
| Page | URL | Description |
|---|---|---|
| Home | / |
Overview and first-time setup wizard |
| Status | /system-status |
System metrics, network, modem, MQTT, WireGuard |
| Settings | /system-settings |
Settings menu aggregator |
| Mode Select | /mode-select |
Enable / disable radio protocols |
| DMR | /mode-dmr |
Callsign, DMR ID, SSID, server, frequencies, color code |
| POCSAG / DAPNET | /mode-pocsag |
Frequency, DAPNET server/auth, RIC, whitelist/blacklist |
| D-Star | /mode-dstar |
Placeholder — not yet implemented |
| YSF | /mode-ysf |
Placeholder — not yet implemented |
| P25 | /mode-p25 |
Placeholder — not yet implemented |
| NXDN | /mode-nxdn |
Placeholder — not yet implemented |
| WiFi | /system-wifi |
6-slot credential management, AP settings, WiFi scan |
| Firmware | /system-firmware |
OTA download/flash for ESP32 and modem |
| Admin | /system-admin |
Logs, factory reset, service restart, reboot |
| MQTT | /system-mqtt |
Broker, auth, topics, hardware interval, command token |
| WireGuard | /system-wireguard |
Keys, endpoint, DNS, allowed IPs |
| SD Card | /system-sdcard |
Status, database download/sync, file browser |
| Serial Monitor | /system-serialmonitor |
MMDVM UART settings, baud rate, pins |
| System Info | /system-info |
Chip model, memory, partitions |
| RF Settings | /settings-mmdvm |
RX/TX frequency, color code, RF power, CW ID |
When MQTT is enabled the device subscribes to the configured command topic. A token is always required — commands without a valid token are rejected. Configure a token under System → MQTT → Command Token.
{"cmd": "reboot", "token": "your_token"}
{"cmd": "get_hardware", "token": "your_token"}
{"cmd": "get_status", "token": "your_token"}| Command | Description |
|---|---|
reboot |
Restart the ESP32 immediately |
get_hardware |
Publish hardware info JSON to the hardware topic |
get_status |
Publish {"status":"online","uptime_seconds":N} to the status topic |
On connect the device publishes an announce message listing all available commands and confirming that a token is required.
The firmware runs on FreeRTOS with tasks pinned to specific cores:
A separate low-priority DMR Database task runs on Core 0 and performs blocking SQLite / HTTP lookups asynchronously so DMR keepalives are never delayed.
Settings are stored in NVS (Non-Volatile Storage) and persist across reboots. Compile-time defaults live in include/config.h. Priority order:
- NVS (set via web interface or config import)
config.hdefaults (compile-time fallback)
Configuration can be exported as a key=value text file and re-imported, or saved as named snapshots on SD card or LittleFS.
Amateur radio use. See LICENSE file for details.
A modular, web-configurable, multi-mode digital voice and paging hotspot for amateur radio, built on ESP32 with FreeRTOS. Supports DMR, D-STAR, YSF, P25, NXDN, POCSAG, DAPNET, MQTT, WireGuard VPN, and more.
- Platform: ESP32 (FreeRTOS, Arduino framework)
- Web UI: Responsive, modern interface for configuration, monitoring, and management
- Storage: Internal flash (LittleFS) and SD card support
- Firmware Updates: OTA for both ESP32 and MMDVM modem
- Security: WireGuard VPN, user authentication
- main.h: Main dashboard and landing page. Shows callsign, device hostname, feature highlights, and setup wizard for first-time users.
- system_files.h: System Files page. File browsers for LittleFS and SD card, bootlogos installer, and file management tools.
- system_status.h: System Status page. Live status cards for station info, WiFi, Ethernet, MMDVM hardware, and more.
- system_info.h: System Information page. Hardware, firmware, memory, and task details.
- system_hardware.h: Hardware Settings page. Configure GPIO pins, OLED, SD card, and save/reboot controls.
- mode_.h, service_.h: Additional pages for each digital mode and service (DMR, D-STAR, YSF, P25, NXDN, POCSAG, DAPNET, MQTT, Telegram, WireGuard).
- Main Page: "On Air" status, Last 15 Calls, DAPNET Messages, POCSAG Queue.
- System Files: LittleFS File Browser, SD Card Browser, Bootlogos Installer.
- System Status: Station Information, WiFi Status, Ethernet Status, MMDVM Hardware Status.
- System Info: System Hardware, Memory, Task Stack Usage, All Tasks.
- System Hardware: LED & Button Settings, OLED Settings, SD Card Settings.
- system_*.h/cpp: Core system modules for WiFi, Ethernet, webserver, OLED, SD card, logger, NTP, firmware, modem, etc.
- web_handlers_*.h/cpp: HTTP API endpoint handlers for admin, config, WiFi, bootlogos, snapshots, and more.
- config.h: Central configuration header for all system and hardware settings.
- firmware/: MMDVM modem firmware.
- mmdvm/: Digital voice protocol implementations.
- src/: Additional source code (e.g., WireGuard).
- images/: Bootlogos and UI assets.
- boards/: Board definitions.
- factory-setup/: Factory setup sketches and configs.
- Navigation: Sidebar/menu for all pages.
- Live Status: Real-time cards for radio activity, hardware, and network.
- File Management: Upload, download, delete, and organize files on both flash and SD card.
- Bootlogos: Download and install logo packs directly from the web UI.
- Hardware Settings: Configure pins and peripherals with instant feedback.
- OTA Updates: Update firmware for both ESP32 and modem from the browser.
- Snapshots: Save/load full configuration snapshots to flash or SD card.
Amateur Radio Non-Commercial License
This project is open source for amateur radio use only.
You are free to:
- Use the software for amateur radio operations
- Study, modify, and improve the code
- Share and distribute modifications
- Contribute improvements back to the project
Under the following conditions:
- Non-Commercial: You may NOT use this software for commercial purposes
- Amateur Radio Only: This software is intended exclusively for licensed amateur radio operators
- Attribution: You must give appropriate credit to the original authors (PD2EMC & PD8JO)
- Share Alike: If you modify and distribute this software, you must use the same license
Specifically prohibited:
- Commercial sale of this software or derivatives
- Commercial hardware products using this software without explicit permission
- Use by unlicensed individuals for radio transmission
- Any commercial exploitation of the codebase
Legal Requirements:
- Valid amateur radio license required for operation
- Compliance with local radio regulations mandatory
- Proper station identification required per your jurisdiction
For commercial licensing inquiries, contact the authors.
- MMDVM Project: https://github.com/g4klx/MMDVM
- MMDVMHost: https://github.com/g4klx/MMDVMHost
- BrandMeister Network: https://brandmeister.network/
- Pi-Star: https://www.pistar.uk/
- ESP32 Arduino: https://github.com/espressif/arduino-esp32
- JumboSPOT: https://www.amateurwireless.com/
- MMDVM_HS: https://github.com/juribeparada/MMDVM_HS
- ZUMspot: https://www.zumspot.com/
- RadioID.net Database: https://radioid.net/
- BrandMeister Dashboard: https://brandmeister.network/
73 and enjoy your ESP32 MMDVM Hotspot!
This project is for licensed amateur radio operators only. Not for commercial use.
Developed by PD2EMC & PD8JO