Controlling The Garmin HUD With Bluetooth


The Garmin HUD is a very neat device, putting all your navigational info, from ETA, what lane you should be in, and distance to your next turn right on your windscreen in a heads-up display. The only problem with the Garmin HUD is that it only works with the official Garmin app, despite being a Bluetooth device. Now, someone is finally digging in to the Garmin HUD protocol, allowing anyone to control this HUD from a cell phone, tablet, or computer.

Being completely unable to disassemble the Navigon app for the HUD, [gabonator] decided the only thing to do would be to open up the device and take a peek at some of the packets travelling between the microcontroller and bluetooth module.

[gabonator] expected human readable ASCII characters, but after looking at the nonsense decoded from his oscilloscope and decoding them manually, he tried simply looking at the display in operation to understand how the protocol worked. He got it all decoded, and managed to get a Sygic Navigation program working with this Garmin HUD. You can check out a video of that below.

Thanks [Kevin] for the tip.


  1. RunnerPack says:

    For less than $150, you could just build your own “windshield projector” out of an LCD and talk to it however you want… But, teaching stupid companies that it’s a waste of time to try to lock down their hardware is always worth it, so way to go, [gabonator]!

    • muriani says:

      LCDs are rarely bright enough, especially during the day.
      Also, being in direct or near-direct sunlight in some climates would damage an LCD pretty quickly. I’d be lucky to get a single summer’s use here in Texas.
      At night, you’ll tend to get backlight bleed which results in the screen being a somewhat bright rectangle in your field of view.
      OLED might work fairly well for this, dunno about longevity in sunlight, however.
      VFDs are currently the best choice, due to high brightness and contrast for the price. Just wish I could get a decent dot-matrix VFD for cheap.

      • RunnerPack says:

        While those are all valid points, you’ll note that I said “build [one] out of an LCD. I didn’t mean just slapping an LCD up on the dash. Active cooling (like that in a DIY projector) would help with the longevity, and a Watt or three of LEDs would help with the backlight brightness problem. A better quality LCD might reduce backlight bleed, and the backlight can easily be dimmed (automatically or manually) for nighttime use.

        BTW, I have some VFDs you might be interested in. Your site is down, but I’ll try to contact you with details (or you can reach me via my user name @ GMail)

        • muriani says:

          My site’s down?
          Might have been a connection hiccup. Seems to be up now… thanks for the heads up though. Cable’s decently fast, but not necessarily the most stable

          I may indeed be interested in the VFDs, same contact scheme for gmail, twitter.

  2. RunnerPack says:

    Also, it’s kinda cool that there’s still a market for (and thus, manufacturing facilities for) VFDs.

  3. XOIIO says:

    Finally someone has started making windshield projected displays, I’ve thought this should be a thing for ages.

  4. fartface says:

    expected human readable ASCII characters,

    This is a big mistake, it is the exception to ever see anything “human readable” from a device for it’s protocol. It is nasty wasteful to send human readable, binary packed is far more efficient.

    Glad to see he got it hacked, what I like for this is using it for other uses. that “hud” would actually make the best GPS display for a motorcyclist if repackaged into a waterproof display that could be permanently mounted and reversed so that it displays correctly.

    Why on a motorcycle we are stuck with utter crap for GPS that is at criminal pricing I’ll never understand.

  5. J.C. Wren says:

    Not having seen one of these displays in action, how good are they? Are they sunlight readable at all?

    I’ve idly given thought in the past to trying cobbling something together using a backlit display of some kind, but never got ambitious enough.

    • Oxide says:

      I got one of these as a Christmas gift, sans the helper app. The VFD is excellent across all lighting conditions, and the device has an ambient light sensor to automatically dim on the fly.

      This hack is a godsend. I know what my summer project is going to be.

  6. I’m more interested in the software side. What edition of Sygic is this (Fleet Navigation on Windows etc?) and what’s the integration like? As cool as this undoubtedly is, and it’s a great hack, I’m far more excited by the prospect of hooking up an Arduino with a couple of servos and some LEDs to give a really custom embedded navigation experience.

  7. Great Work!
    Newer Buicks have a great HUD – several colors if not full color – It would be great to see one pulled out of a salvaged LaCrosse or a replacement ordered and tinkered with. If nothing else just seeing what screen GM is using could lead to an opensource Heads Up!

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