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

(github.com)

46 points by mogrinz1 day ago

3 comments

mogrinz1 day ago
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</a>)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</a> You can also install directly from the Arduino IDE Library Manager (search for AMT630A)
- netsharc1 hour ago
 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...</a>
 - mogrinz1 hour ago
 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
- theamk2 hours ago
 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)
 - aaronblohowiak2 hours ago
 the video goes into a lot of this. it is far above average YouTube quality.
- Retr0id2 hours ago
 Heads up, your youtube link has a tracking ID in it that is bound to the account/device you shared the link from.
 - genxy1 hour ago
 This video on the device itself (from the readme), not about the robot suit itself.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</a>
 - mogrinz1 hour ago
 Thanks! I’ll fix that
- ls-a2 hours ago
 [dead]
bobsmooth1 hour ago
Classic bit of reverse engineering. I love how detailed your readme is.
BugsJustFindMe1 hour ago
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".
- john_strinlai23 minutes ago
 "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</a>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...</a>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...</a>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> <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...</a>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> <a href="https://www.caranddriver.com/car-accessories/g44411856/best-backup-cameras-tested/" rel="nofollow">https://www.caranddriver.com/car-accessories/g44411856/best-...</a>it's safe to say that "backup camera" is perfectly acceptable.
- Steve4436 minutes ago
 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.
 - mogrinz24 minutes ago
 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> A search for “reverse camera” only returns “backup camera”s