Skip to content

Flipper_Zero_Lora_Terminal

Directory actions

More options

Directory actions

More options

Latest commit

 

History

History

Flipper_Zero_Lora_Terminal

Folders and files

NameName
Last commit message
Last commit date

parent directory

..
FlipperPic
FlipperPic
 
 
README.md
README.md
 
 
lora_terminal.fap
lora_terminal.fap
 
 

README.md

Flipper Zero LoRa Terminal

A Flipper Zero application (.fap) that turns the Flipper into a full-featured controller for the DX-LR20 STM32 LoRa board — no laptop required. Send messages, sniff packets, scan frequencies, configure radio parameters, and run AES-encrypted chat — all from the Flipper's screen and buttons.

Flipper Radio Interface Category

Requires: A DX-LR20 LoRa board running the STM32_DX-LR20_LORA firmware.

Features

Scene What it does
Send Message On-screen keyboard to type and transmit LoRa text messages
Sniff Packets Continuous receive mode — scrolling display of incoming packets with RSSI/SNR
Frequency Scan RSSI sweep across 433 / 868 / 915 MHz bands (or all at once)
Radio Config Live-adjust all 13 radio parameters without recompiling
Encrypted Chat Join XTEA-encrypted chat rooms — full duplex with live RX, press OK to compose
Mesh Listen Meshtastic passive listener — pick preset + region, auto-decrypts with AES-128
Radio Status Query and display the current radio configuration at a glance
About Project info, hardware details, and GitHub link

Installation

  1. Download lora_terminal.fap from this folder.
  2. Copy it to your Flipper Zero SD card: 
    SD Card/apps/GPIO/lora_terminal.fap
  3. On the Flipper, navigate to Apps → GPIO → LoRa Terminal.

You can copy the file using:

  • qFlipper (desktop app — drag and drop)
  • Flipper Zero mobile app (File Manager)
  • Direct SD card access (pop the micro SD and use a reader)

Project Picture

Simplest Flipper module possible.

Front

Diagram

Back

Diagram

Wiring — Flipper Zero to DX-LR20 Board

Only 3 wires are needed. Both devices operate at 3.3V logic — no level shifter required.

 Flipper Zero                    DX-LR20 / STM32 Board
 ────────────                    ──────────────────────
 Pin 13 (TX)  ──────────────────→  PA10 (RX)
 Pin 14 (RX)  ←──────────────────  PA9  (TX)
 Pin 8  (GND) ──────────────────→  GND

Flipper GPIO Header Reference

              Flipper Zero (top edge, screen facing you)
         ┌──────────────────────────────────────────────┐
         │  1  2  3  4  5  6  7  8  9 10 11 12 13 14    │
         │ 15 16 17 18 19 20 21 22 23 24 25 26 27 28    │
         └──────────────────────────────────────────────┘

  Pin  1 = +5V             Pin  8 = GND
  Pin 13 = USART TX (PA14) Pin 14 = USART RX (PA13)
Flipper Pin Signal Direction STM32 Pin Notes
1 +5V Power OUT 5V / VIN Powers the LoRa board (see below)
8 GND Ground GND Common ground — always connect
13 TX Flipper → STM32 PA10 (RX) UART data to board
14 RX STM32 → Flipper PA9 (TX) UART data from board

Powering the LoRa Board from the Flipper

The Flipper Zero can supply 5V @ ~400 mA from Pin 1 on the GPIO header when running on battery (higher when USB-connected). The DX-LR20 board draws approximately 80–120 mA during TX at +22 dBm and under 30 mA during RX/idle — well within the Flipper's budget.

Wiring for Flipper-Powered Operation (4 wires)

 Flipper Zero                    DX-LR20 / STM32 Board
 ────────────                    ──────────────────────
 Pin  1 (+5V) ──────────────────→  5V  (VIN)
 Pin  8 (GND) ──────────────────→  GND
 Pin 13 (TX)  ──────────────────→  PA10 (RX)
 Pin 14 (RX)  ←──────────────────  PA9  (TX)

Important: Connect 5V to the board's 5V/VIN pin (not the 3.3V pin). The STM32 board has its own 3.3V regulator that will step down from 5V.

Building a Self-Contained Module

To build a clean, portable Flipper + LoRa module:

Parts needed:

Part Purpose Approximate Cost
DX-LR20 STM32 LoRa board LoRa radio + MCU ~$5–8
4× female-to-female Dupont jumpers Wiring harness ~$1
Flipper Zero GPIO pin header (2×7 female) Board-side connector ~$0.50
Small piece of protoboard (optional) Mount point ~$1
Heat shrink tubing (optional) Strain relief / insulation ~$1

Assembly steps:

  1. Flash the STM32 board with the DX-LR20 LoRa firmware using PlatformIO or a HEX flasher (STLink / USB-Serial + boot0 jumper).

  2. Prepare the wiring harness — cut 4 Dupont jumper wires to equal length (~8–10 cm). Use color coding:

    • 🔴 Red → 5V power (Pin 1 → VIN)
    • ⚫ Black → Ground (Pin 8 → GND)
    • 🟢 Green → TX (Pin 13 → PA10)
    • 🔵 Blue → RX (Pin 14 → PA9)

  3. Solder or connect the wires to the DX-LR20 board header pins (5V, GND, PA10, PA9).

  4. Optional — protoboard mount: Solder the DX-LR20 board onto a small piece of protoboard. Add a 2×7 female pin header that plugs directly into the Flipper's GPIO. Route the 4 traces/wires from the header to the board pads. This creates a clean plug-in module.

  5. Optional — case: Use heat shrink or a 3D-printed enclosure to protect the board and antenna connection.

  6. Antenna: Ensure a proper antenna is connected to the DX-LR20 board's SMA/u.FL connector. Never transmit without an antenna — this can damage the SX1262 PA.

Wiring Diagram

                    Flipper GPIO Header (top view)
    ┌─────────────────────────────────────────────────────────────┐
    │ [5V]  2   3   4   5   6   7  [GND]  9  10  11  12 [TX] [RX] │
    │  15  16  17  18  19  20  21   22   23  24  25  26  27   28  │
    └─────────────────────────────────────────────────────────────┘
      │                             │                     │    │
      │ Red                         │ Black               │    │
      │                             │               Green │    │ Blue
      ▼                             ▼                     ▼    ▼
    ┌─────────────────────────────────────────────────────────────────┐
    │                     DX-LR20 LoRa Board                          │
    │                                                                 │
    │  [5V/VIN]  [GND]  [PA9/TX]  [PA10/RX]            [SMA Antenna]  │
    │                       │          │                       │      │
    │                       └──────────┘                       │      │
    │                       UART to Flipper              Antenna      │
    └─────────────────────────────────────────────────────────────────┘

Usage Guide

Main Menu

When you launch the app, you'll see eight options:

  1. Send Message — Opens the Flipper keyboard. Type your message and press Enter to transmit via LoRa.

  2. Sniff Packets — Puts the radio in continuous RX. Incoming packets scroll on screen with RSSI, SNR, hex dump, and Meshtastic decode (if enabled). Press Back to stop.

  3. Frequency Scan — Choose a band (All / 433 MHz / 868 MHz / 915 MHz). The board sweeps the band and reports RSSI levels at each step. Results scroll on screen.

  4. Radio Config — Scroll through 13 radio parameters and adjust with Left/Right:

    • Frequency: 433.000 / 433.125 / 868.000 / 868.100 / 915.000 / 906.875 MHz
    • Modem: LoRa or GFSK
    • Spreading Factor: SF5 through SF12
    • Bandwidth: 7.8 kHz to 500 kHz (10 options)
    • Coding Rate: 4/5 through 4/8
    • TX Power: -9 to +22 dBm
    • Preamble: 4 / 8 / 12 / 16 / 32 / 64 symbols
    • CRC: On or Off
    • IQ Polarity: Normal or Inverted
    • Sync Word: 0x12 (Private) or 0x34 (Public)
    • Header Mode: Explicit or Implicit
    • LDRO: Auto / On / Off
    • RX Boost: On or Off

    Changes are sent to the board immediately — no save step needed.

  5. Encrypted Chat — Pre-filled with default room "Flipperchat 12345678" — edit or press OK to join. Once joined:

    • Incoming messages appear automatically (live RX)
    • Press OK to compose and send a message
    • Press Back to leave the room
    • Encryption: XTEA-CTR with SipHash-2-4 MAC

  6. Mesh Listen — Meshtastic passive listener:

    • First, pick a preset: LongFast (SF11/BW250), LongSlow (SF12/BW125), or ShortFast (SF7/BW250)
    • Then pick a region: US, EU868, EU433, CN, JP, ANZ, KR, TW, IN, RU
    • The board auto-configures all LoRa parameters and starts sniffing
    • Received Meshtastic packets are decrypted (AES-128-CTR) and decoded
    • Press Back to stop and return

  7. Radio Status — Sends the status command and displays the current radio configuration.

  8. About — Project info, hardware details, encryption methods, and GitHub link.

Tips

  • Antenna first: Always connect an antenna to the DX-LR20 board before transmitting.
  • Range check: Use low SF and high BW for close-range speed, high SF and low BW for maximum range.
  • Packet sniffing: Both sides must use the same frequency, SF, BW, CR, and sync word to see each other's packets.
  • Power draw: At +22 dBm, the radio draws ~120 mA during TX. Lower the TX power if you need to conserve Flipper battery.
  • 5V auto-power: The app automatically enables 5V on GPIO Pin 1 when launched and disables it on exit.

Compatibility

Requirement Details
Flipper Zero firmware Official firmware (latest release recommended)
STM32 board firmware STM32_DX-LR20_LORA
UART 115200 baud, 8N1
Logic levels 3.3V (native on both devices)
Power 5V from Flipper Pin 1, or external USB to the STM32 board

Troubleshooting

Problem Solution
App shows no response Check wiring — TX/RX may be swapped. Flipper TX goes to STM32 RX (PA10).
Garbled text on screen Verify both ends are set to 115200 baud. Reset the STM32 board.
Board not powering on from Flipper Ensure 5V goes to the board's VIN/5V pin, not the 3.3V pin. Check GND.
"No packets" during sniff Confirm a transmitter is active on the same frequency, SF, BW, CR, and sync word.
Short range Attach a proper antenna. Increase SF and decrease BW for longer range.
Flipper battery drains fast Reduce TX power (Radio Config → TX Power). Avoid continuous TX (beacon mode).

License

This project is open source and available for personal and educational use. See the main repository for details.