OAK-D SR POE Trigger Issue

driupin

Hi Everyone,

I'm having an issue with my OAK-D SR POE camera. I'm trying to figure out how to capture frames from the left and right cameras, as well as the stereo depth map, using a trigger signal. I'm supplying a 12V signal to pins 2 and 7 of the M8 connector and using the code example oak_deptahi_external_trigger_fsync.py from the "Frame Synchronization" page of the documentation.

The camera triggers once after I start it (the window for it opens), but then it freezes. However, the RGB image from the TOF sensor keeps streaming. I've tried using a 5V signal, but the behavior remains the same. I've also noticed that the current from the trigger is more than 20mA, but I'm using a power supply with current limiting.

Is this related to the trigger pins I'm using, or could something else be causing the camera to freeze?

Thank you!

jakaskerl

driupin
FSIN input is 5V only. Don't put more -- will add it to docs, sorry about that.

I'll link you to the docs on how to use the trigger there.

Thanks,
Jaka

driupin

jakaskerl
Thank you for the quick response. I tried the setup on another camera using a 5V signal, but the same code didn’t work there either. As soon as the program starts, the frames begin streaming immediately, and upon the first trigger signal, the cameras freeze again, though the TOF sensor continues working.

I also experimented with switching from pin 7 to pin 8 and tried using resistor pull-ups, but the result remained the same.

jakaskerl I'll link you to the docs on how to use the trigger there.

I’d appreciate any links to the documentation.

Thanks again,
Andrei

jakaskerl

https://docs.luxonis.com/hardware/platform/deploy/m8_m12_connectors/

driupin

jakaskerl

Many thanks for your answer! Your setup worked great. Now the camera only sends images after it gets a trigger. However, I've run into a new issue: there's a delay between receiving the trigger and taking the shot. The documentation diagram shows that the image capture starts instantly, but my STROBE measurements show there's a 24 ms delay between the trigger and the signal. Am I right in thinking that the STROBE is linked to the sensor's exposure time? If so, is there a way to reduce this delay?

Also, could you explain why there are multiple pulses on the strobe, with at least two pulses, when changing the "discard" frame and "burst" frame in trigger settings?

Thank you,
Andrei.

jakaskerl

driupin
For this to work fast enough, set the fps to 999 (this will clamp the FPS to highest possible rate of that sensor) so the time between trigger and capture is as low as possible.

driupin Also, could you explain why there are multiple pulses on the strobe, with at least two pulses, when changing the "discard" frame and "burst" frame in trigger settings?

IIRC setting externalTrigger(1, 0) should only pulse once. -- 1 burst frames and 0 discarded.

Thanks,
Jaka