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

81 points · 25 comments · mogrinz

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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. ls-a · 1790784605 · focus · HN ↗
  [dead]
2. theamk · 1790786760 · focus · HN ↗
  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)
  1. aaronblohowiak · 1790787463 · focus · HN ↗
    the video goes into a lot of this. it is far above average YouTube quality.
3. Retr0id · 1790787569 · focus · HN ↗
  Heads up, your youtube link has a tracking ID in it that is bound to the account/device you shared the link from.
  1. genxy · 1790788222 · focus · HN ↗
    How I See from Inside Robby — AMT630A Heads-Up Display <a href="https://www.youtube.com/watch?v=0eQ94DHOay0" rel="nofollow">https://www.youtube.com/watch?v=0eQ94DHOay0
  2. mogrinz · 1790789928 · focus · HN ↗
    Thanks! I’ll fix that
    ThePowerOfFuet · 1790801544 · focus · HN ↗
    Still not fixed :(
    Replace it with: <a href="https://youtu.be/gAHd46ErNA8" rel="nofollow">https://youtu.be/gAHd46ErNA8
    mogrinz · 1790813694 · focus · HN ↗
    Yeah, I didn’t realize there was a time limit on edits, and I was well outside of it
4. genxy · 1790787911 · focus · HN ↗
  This is super cool, would you drop a link to the exact device you used? I can't find it referenced in your github nor the yt video.
5. 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...
6. jakzurr · 1790797664 · focus · HN ↗
  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?
  1. keanebean86 · 1790798593 · focus · HN ↗
    "can we legally post the teardown video of this to hacker news?"
7. ThePowerOfFuet · 1790801587 · focus · HN ↗
  Tracking-free YouTube link: <a href="https://youtu.be/gAHd46ErNA8" rel="nofollow">https://youtu.be/gAHd46ErNA8
  @dang Could HN remove source identifiers from links by default?
BugsJustFindMe · 1790788823 · focus · HN ↗
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".
1. Steve44 · 1790793015 · focus · HN ↗
  I think this may be a case of language evolving/devolving and quite possibly an Americanism.
  I'm British and to me backup means having a reserve or spare ready to use. You have a battery backup on your servers to step in when there is a mains problem, a photographer will have a backup camera, you backup you files regularly etc.
  We would call this a reversing camera, for when you reverse your car using the Reverse gear. You can back into a parking space, or even just back up a little bit into a better spot.
  One thing I'm seeing which irritates me is people are starting to call backing singers backup singers. They are not a backup the the lead singer, that would be an understudy, they are supporting like the backing on picture.
  1. mogrinz · 1790793732 · focus · HN ↗
    Fwiw, I used the same phrasing in my title as the product I bought on Amazon. Most of these are made (and packaged) in China: <a href="https://www.amazon.com/s?k=backup+camera" rel="nofollow">https://www.amazon.com/s?k=backup+camera A search for “reverse camera” only returns “backup camera”s
    zoo · 1790805911 · focus · HN ↗
    At least the naming convention has redundancy, unlike most people's actual backups
  2. justin66 · 1790797901 · focus · HN ↗
    [delayed]
2. john_strinlai · 1790793783 · focus · HN ↗
  "backup camera", no hyphen or space, is at least popular enough to have a wikipedia entry.
  <a href="https://en.wikipedia.org/wiki/Backup_camera" rel="nofollow">https://en.wikipedia.org/wiki/Backup_camera
  it is also used very regularly elsewhere, like government sites: <a href="https://www.nhtsa.gov/vehicle-safety/driver-assistance-technologies" rel="nofollow">https://www.nhtsa.gov/vehicle-safety/driver-assistance-techn...
  or legal advice sites: <a href="https://thelegalguide.org/are-backup-cameras-required-all-cars-united-states/" rel="nofollow">https://thelegalguide.org/are-backup-cameras-required-all-ca...
  or news sites: <a href="https://abcnews.com/US/cars-us-now-required-backup-cameras/story?id=54854404" rel="nofollow">https://abcnews.com/US/cars-us-now-required-backup-cameras/s... <a href="https://www.reuters.com/article/business/consumer-groups-sue-us-over-delay-in-backup-camera-rule-idUSBRE98O03Z/" rel="nofollow">https://www.reuters.com/article/business/consumer-groups-sue...
  or automotive magazines: <a href="https://www.autoweek.com/news/a1892066/feds-backup-cameras-all-new-cars-2018/" rel="nofollow">https://www.autoweek.com/news/a1892066/feds-backup-cameras-a... <a href="https://www.caranddriver.com/car-accessories/g44411856/best-backup-cameras-tested/" rel="nofollow">https://www.caranddriver.com/car-accessories/g44411856/best-...
  it's safe to say that "backup camera" is perfectly acceptable.
3. ssl-3 · 1790799751 · focus · HN ↗
  [delayed]
bobsmooth · 1790789850 · focus · HN ↗
Classic bit of reverse engineering. I love how detailed your readme is.
dayvid · 1790801416 · focus · HN ↗
nocash behind no$gba and no$nes has an article on this as well <a href="https://problemkaputt.de/amt630a.htm" rel="nofollow">https://problemkaputt.de/amt630a.htm

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