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Pixy and image transfer

Pixy Hardware
#1

Hello everyone,

I’m just discovering the pixy product, and sounds like a very good project.

I’m actually working with two development boards, one based on the NXP LPC43xx (same family as the one in the pixy (M4-M0 cores)) and one Freescale Vybrid Vf6xx (A5-M4 cores).
I want to test the camera interface of the two processors by connecting a camera to each one, take snaps and send the data through USB to PC.
(I’m not really interested in object detection etc… just in taking simple pictures)

As the Pixy provide an embedded LPC43xx, I won’t need to connect it to my LPC43xx board to test this interface, for the Vybrid I don’t know how to do because I want to use the camera interface in the Vybrid instead of LPC43xx one.

As I understand you use an Arduino or simple micro to process on the objects data etc (things that I don"t need - I just want to transfer pictures taken from the cam to my PC through USB).

1 - My questions are, would Pixy corresponds to my boards and my project ?
2 - I’ve seen the schematic of the Camera, the camera is interfacing the LPC43xx with the SGPIO interface right ?
3 - Would I be able to transfert the pictures through USB (without special processing) ?
4 - How can I do if I want to test it on my Vybrid Board ?

I’m still reading about the Pixy, if anyone have any idea/hint , would be very helpful,

Best regards,

Ahmed.

#2

Hi Ahmed,

I think you may have a slight misunderstanding of how Pixy works. It does not send the images to an external micro for processing. All of the object detection occurs on Pixy’s NXP LPC.

  1. How exactly do you want them to communicate? Currently the Pixy libraries do not support sending image data to external micros.
  2. Yes.
  3. No. If you have the right development tools you can write the code to do this yourself.
  4. There aren’t really any good ways to do this since there aren’t any pinouts connected to the camera interface. The camera interface wires are barely exposed on the PCB since the camera sensor is covered by the lens and the micro IC is a BGA package.

Scott

#3

Hi Scott,

Thank you for your answer, it’s more clear now,

So if I just want to use the pixy with the pixylibs, would I be able to send the images throught USB to my PC (in Bulk mode for example) ?

How do you use USB in your application, because you are sending the video data through USB to the pixyMon application right ? (with DeviceClass 0xFF, bulk mode etc.)

Ahmed

#4

Hi Ahmed,

We use libusb for our USB driver. To send over the video we first define the codec with “FourCC”:http://fourcc.org/fourcc.php and send over the actual pixel data in the codec specified. You can see how it is interpreted in Pixymon “here”:https://github.com/charmedlabs/pixy/blob/master/host/pixymon/renderer.cpp. Looking through that code you should get a better understanding of the format.

Hope this helps.

Scott