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Reverse-engineering a $35 backup camera display (AMT630A)

github.com

83 points by mogrinz · 28 comments

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mogrinzOP

This started because I built a full-size Robby the Robot suit and discovered I couldn't actually see out of it (https://youtu.be/gAHd46ErNA8?si=-iOwbobp4trPXdGB)

I bought a $35 backup camera/display to solve that problem, then discovered that the display contained an AMT630A video processor with a surprisingly capable OSD system. That sent me down a rabbit hole of I2C probing, firmware dumping, register tracing, custom graphics, bitmap formats, hidden factory menus, and eventually figuring out how to use an ESP32 to generate a programmable HUD over the live composite video.

I ended up turning what I learned into an Arduino library, which I've released on GitHub. It supports built-in and custom fonts, multiple OSD windows, 16-color bitmaps, palettes, transparency, and animation. It can also be used with composite video sources other than the camera.

The library and code are here: https://github.com/mogrinz/AMT630A You can also install directly from the Arduino IDE Library Manager (search for AMT630A)

  • netsharc

    Hah, the video is more exciting than the readme, IMO an image of the robot in the readme would be attention-getting.

    Would "rear view mirrors" help navigation in the suit? So 2 extra displays that would give you a view of what's over your shoulder, like on some cars nowadays (for example): https://www.carscoops.com/2022/02/heres-what-you-wanted-to-k...

    • mogrinzOP

      The setup I bought only has one camera but the AMT supports up to 3 separate composite sources (I did not add switching to the library yet b/c I couldn’t test this). It looks like split-screen is supported also. For now, I am adding some simple sensors to the back of the suit and triggering an on-screen pop-up when something is behind me

    • jakzurr

      Holy smokes I like that. Maybe it will catch on, I dunno.

      • netsharc

        Cameras are rear view mirrors? Audi e-trons have them, they're also available as option on Hyundai Ioniqs. But apparently it's unlawful to not have physical side mirrors in North America...

  • theamk

    Neat! Can you add the pictures of your setup? Display, soldered wires, some overlays?

    (sorry if they in the video - I generally don't watch the videos before reading the text first)

  • ThePowerOfFuet

    Tracking-free YouTube link: https://youtu.be/gAHd46ErNA8

    @dang Could HN remove source identifiers from links by default?

  • jakzurr

    About 12 minutes into the first vid, the thought struck me: How will the EMT's react to a guy stuck halfway inside a Robby the Robot suit?

  • Retr0id

    Heads up, your youtube link has a tracking ID in it that is bound to the account/device you shared the link from.

dayvid

nocash behind no$gba and no$nes has an article on this as well https://problemkaputt.de/amt630a.htm

bobsmooth

Classic bit of reverse engineering. I love how detailed your readme is.

BugsJustFindMe

Title nit: "backup" means a second copy, "back up" is the verb phrase for moving backwards. Verb phrases get hyphenated for clarity when used as adjectives immediately preceding a noun. So this should be "back-up camera", not "backup camera".

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