Depthai runtime error

[buckethead11]

Hi, I am using the Luxonis Rpi Compute module 3 and am having some trouble with the depthAI.

I replaced the SD card that came with the device with another one and used the Raspbian image provided on the Luxonis website to install the OS. After that I followed the steps on the website https://docs.luxonis.com/projects/api/en/latest/install/ to install the necessary dependencies and the library. It is now currently running depthAI-2.5.0.0.

When I tried running the depthai_demo program I got a runtime error: “Couldn’t read data from stream: ‘__rpc_main’ (X_LINK_ERROR)”. However, when I tried running programs from the depthai-python library, every program that did not use depth worked fine. The RGB video, mono camera, all worked fine but as soon as depth was involved, I got this same error. I was wondering what I could do to fix this problem. Thank you.

[Luxonis-Brandon]

Hi @buckethead11 ,

Sorry for the trouble here and sorry about the delay. So it sounds like there's a problem with one of the grayscale cameras. One thing that seems to often be the problem is that the FFC under the grayscale cameras can be pushed on accidentally when handling the device, which will "pop out" (or worse, partially pop out) the connector to the grayscale camera. Some examples are below:

FFC popped out: Notice that it's not super easy to see from the top:

On new production of these, we have a pad under there that eliminates this potential. I'm not 100% sure if this is the problem, but from the description I think what is happening is the FFC connector is partially popped out, so that the camera module is probably still connected to some lines (say I2C) and not others (say MIPI) to the point where the firmware gets confused and crashes (causing the error you see).

Thoughts?

Thanks, Brandon

[johngaebler]

Hey @buckethead11

I'm not having an issue related to yours except I am lacking the SD card with the OS installed, can you point me to where you found the Raspbian image provided on the Luxonis website so I can also install the OS on my own SD?

Thanks

[Luxonis-Brandon]

Hi @johngaebler ,

So on this issue - more recent DepthAI Pi Compute Module Editions ship with a Pi Compute Module with onboard eMMC storage (which is a bit more reliable for operating system usage than microSD cards).

So I just wanted to mention that in case you are thinking you cannot boot the unit because you don't see a uSD card. And then to check on what issue you may be running into. The reason I want to dig into this as well is that for these eMMC versions, the eMMC is actually used instead of the uSD card and I think some configuration needs to be changed (which I'd need to research) to boot off of uSD card instead.

Thoughts?

Thanks, Brandon