Hard Hat Brigade Flipper Zero App

June 26, 2025 ยท View on GitHub

Flipper Zero app. This application sends infrared messages to the hardhat that will be available at DEF CON 33.

Running the application

Launch app on Flipper Zero, type your message, point the device at the receiver, and press Save. After a brief pause and a vibration, the message is transmitted. Once you see "Message sent" and hear the success tones, the hardhat should display your message.

Installing the application

Copy the hhb_ir_app.fap file to your Flipper Zero's SD Card, in the Apps/Infrared folder.

On the Fliper Zero, choose Apps, Infrared, HHB IR App.

Building the app (optional)

This application uses documented APIs, so you can use uFBT tool to build and launch the application. See https://github.com/jamisonderek/flipper-zero-tutorials/wiki/UFBT

  1. Install uFBT tool.
  2. If using custom firmware, switch to target firmware.
  3. Change to the proper channel/branch.
  4. Connect Flipper Zero to your computer and exit any application on the Flipper Zero.
  5. Make sure qFlipper and lab.flipper.net are not running on your computer.
  6. run "ufbt launch"

Technical details

Infrared signals are sent from the Flipper Zero to the hardhat.

  • The protocol used is the NECext protocol:

    • 38 kHz carrier, 33% duty cycle.
    • Preamble: 9.0ms lead/4.5ms space.
    • Data 0: 560uS burst/560uS space. Data 1: 560uS burst/1690uS space.
    • Data is LSB (Least Significant bit first).
    • 16-bit address (sent after preamble).
    • 16-bit command (send after address).
    • End of tx: 560uS burst/110ms space.

  • All messages have an address of 0x1337.

  • Each ASCII character of the message is sent as the command.

  • Additional 50ms delay between messages (transmitted characters).

  • The message is terminated with command 0x4 (EOT).

  • Example: Sending a message of "Q" (ASCII 0x51, followed by 0x4 EOT).

    • Positive number represents microseconds of modulated signals.
    • Negative number is no modulated signal present.
    • 9000 -4500 (Preamble)
    • 560 -1690 560 -1690 560 -1690 560 -560 (1110 -> 0111b = 7)
    • 560 -1690 560 -1690 560 -560 560 -560 (1100 -> 0011b = 3)
    • 560 -1690 560 -1690 560 -560 560 -560 (1100 -> 0011b = 3)
    • 560 -1690 560 -560 560 -560 560 -560 (1000 -> 0001b = 1)
    • 560 -1690 560 -560 560 -560 560 -560 (1000 -> 0001b = 1)
    • 560 -1690 560 -560 560 -1690 560 -560 (1010 -> 0101b = 5)
    • 560 -560 560 -560 560 -560 560 -560 (0000 -> 0000b = 0)
    • 560 -560 560 -560 560 -560 560 -560 (0000 -> 0000b = 0)
    • 560 -110000 (End of sending "Q", 0x51)
    • 9000 -4500 (Preamble)
    • 560 -1690 560 -1690 560 -1690 560 -560 (1110 -> 0111b = 7)
    • 560 -1690 560 -1690 560 -560 560 -560 (1100 -> 0011b = 3)
    • 560 -1690 560 -1690 560 -560 560 -560 (1100 -> 0011b = 3)
    • 560 -1690 560 -560 560 -560 560 -560 (1000 -> 0001b = 1)
    • 560 -560 560 -560 560 -1690 560 -560 (0010 -> 0100b = 4)
    • 560 -560 560 -560 560 -560 560 -560 (0000 -> 0000b = 0)
    • 560 -560 560 -560 560 -560 560 -560 (0000 -> 0000b = 0)
    • 560 -560 560 -560 560 -560 560 -560 (0000 -> 0000b = 0)
    • 560 -110000 (End of sending "EOT", 0x4)

Credits

Code credit goes to @jamisonderek, the majority of the code is taken from his Basic Scenes tutorial, https://github.com/jamisonderek/flipper-zero-tutorials/tree/main/ui/basic_scenes. Check out his YouTube channel here: https://www.youtube.com/@MrDerekJamison