Thread

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

83 points · 25 comments · mogrinz

mogrinz · 1790629590 · focus · HN ↗
This started because I built a full-size Robby the Robot suit and discovered I couldn't actually see out of it (<a href="https://youtu.be/gAHd46ErNA8?si=-iOwbobp4trPXdGB" rel="nofollow">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: <a href="https://github.com/mogrinz/AMT630A" rel="nofollow">https://github.com/mogrinz/AMT630A You can also install directly from the Arduino IDE Library Manager (search for AMT630A)
1. netsharc · 1790788677 · focus · HN ↗
  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): <a href="https://www.carscoops.com/2022/02/heres-what-you-wanted-to-know-about-the-honda-e/" rel="nofollow">https://www.carscoops.com/2022/02/heres-what-you-wanted-to-k...
  1. mogrinz · 1790790275 · focus · HN ↗
    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
    riskable · 1790802313 · focus · HN ↗
    Hm. Have you thought about using a backup camera? =)
  2. jakzurr · 1790796152 · focus · HN ↗
    Holy smokes I like that. Maybe it will catch on, I dunno.
    netsharc · 1790797786 · focus · HN ↗
    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...

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