Connecting a custom UART camera to the Jetson AGX dev. kit

Autonomous Machines Jetson & Embedded Systems Jetson AGX Xavier
#1

Hi!

I’m a developer with no experience in electronics (even searching is complicated…), and I want to use a custom IR camera on the Jetson AGX Developper Kit.

The IR camera is a component of a complete system. It is plugged on a motherboard with a 4 pins micro-JST cable. I want to unplug the camera so I can connect it directly to the Jetson to make a new customizable autonomous system.

The only information I have so far is:

  • the name of the 4 pins on the motherboard: “5V-TX3-RX3-GND”
  • a documentation which mentions using UART (“115200 baud rate, 8 data bits, 1 Stop bit”) to send a request message to the camera so I receive an fixed length answer with several fixed length fields among which the temperature map which I want to process.

Is it possible to do something with so few details?

I see the Jetson AGX has UART connectors on:

  • the 40 pins extension header, which has UART1_TX (pin #8) and UART1_RX (pin #10) beside a 5V and a GND pin.
  • the micro-USB plug beside the extension header (“for UART console”)

And I’ve seen this tutorial using Python with pyserial to use the UART pins of a Jetson nano: https://www.jetsonhacks.com/2019/10/10/jetson-nano-uart/

So there is hope maybe?

Thank you,
François

#3

hello francois.plessier,

just curious about this, I would suspect these 4-pin were using something like USB interface.
may I know which the sensor model it is; could you please have more details about the sensor signaling.

BTW,
there’s camera interface (CSI) that you could connect camera modules for usage, please check Jetson Partner Supported Cameras for the list of cameras supported by Jetson Camera Partners on the Jetson platform.
thanks

#4

Thank you for helping me!

just curious about this, I would suspect these 4-pin were using something like USB interface.

I tried a USB connection, without success.
The USB connection did work for an optical camera which is also part of the system, but this time the motherboard clearly declares a “USB” port.

I read the documentation again, and it actually mentions a “thermal module”. This probably means that I need to communicate with the module board, on which the IR camera is welded. That would explain the need for UART.

Extracting the camera from the module isn’t feasible right now as the module is hot-glued really bad to the system frame and it’s hard to remove it without risking to damage the camera. I was so happy with the optical camera victory, now I start feeling hopeless :-p

may I know which the sensor model it is
I don’t have any information so far. I’m still waiting for the answer of the Chinese supplier of the system, also the module board is glued on the side where the connection names are written…

Given that, can you suggest anything I could try to communicate with the thermal module? Can connecting the thermal module on the 4-6-8-10 pins for UART then use Python/pyserial to send a request and receive the answer work? How would I check if the connection is OK in the first place?

Thank you,
François

#5

IMG_20200705_013633
IMG_20200705_0136332560×1920 2.14 MB

Does look your module like this one, a metal capsule like this?
Do you know the resolution? 8x8 maybe?

#6

Hi!

We finally removed the glue without breaking anything. Here’s the thermal module:
https://drive.google.com/file/d/1-L9xy3H6glSYellkUh5onolbeG0w7sNM/view?usp=sharing
https://drive.google.com/file/d/12rYyFJ80SMhEvkxXugD3Dt1_KjK5Wp9a/view?usp=sharing

(I tried to include image as Markdown but I wasn’t successful)

It’s a Melexis IR sensor, and if I understand correctly it actually has a 1MHz I2C interface. The UART interface would actually be the interface to the mother board, which has an I2C interface with the thermal module.
Meaning we actually need an I2C interface if we want the Jetson to replace the motherboard.

And my problem now has similar problems popping while searching this forum: Jetson Nano I2C problem with access to the IR camera

And I found a tutorial but for Jetson Nano: https://www.jetsonhacks.com/2019/07/22/jetson-nano-using-i2c/

Do you have any suggestion/documentation or tutorial for noob level?
Sorry if my first post was so misleading…
Thank you!

François

#7

hello francois.plessier,

seems there’s permission issue of those two thermal module pictures in google drive.
you might refer to Nano J41 Header Pinout for external connections. there’s also documentation, Configuring the 40-Pin Expansion Header, to introduce Jetson‑IO python scripts for pin configuration.
thanks

#8

(I fixed the permission for the image)

Thank you for the Jetson-IO documentation! I somehow missed it… Now I see I can use the simple 40pin header and a use Python for the I/O interface; I feel more confident :-)

Thanks for the help, have a great day!