Sending an image from open mv to Raspberry Pi over 1000ft

Project Discussion
#1

Hi,

My project is sending an image over 1000ft cable for which I considered open mv cam at the transmission end and the raspberry pi on the receiving end would do good. As we can get jpeg images from the UART3 of the open mv and that image can be processed by the raspberry pi. The idea seems good theoretically but I am stuck at a point where I connected the open mv UART (P4)with raspi’s pin10. And then I don’t know how my code at the open mv end should look like, how my code at raspi end looks like, How should I send the video from open mv, how should I process and display the image that I am getting from Open Mv. It would really be great if anyone can throw some light about how to get this one started and running or what are the best websites that I should read so that I get a clear idea what to do next.

Thank you,
Perini

#2

WOW 100f0t

That’s a long way to maintain signal over a cable.

I have heard of people using old school rs232 at those sort of distances see RS-232 - Wikipedia

You can buy USB to RS232 adapters very cheap but you will have to have a very high quality cable.

Mostly I think people use RF for bigger distances, I do know ESP32 has their own protocol for doing ESP32 to ESP32 over WiFi up to 2km away.

#3

Hi OutoftheBOTS,

Thank you for your suggestions. My actual idea which I was working on a few days back was taking the openmv signals that are the data signal, clk signal, and the RS signal and sending it over a 1000ft cat 5e cable and using the line drivers but the problem which I faced during that time was my data signal and clk signal were not in sync with each other as a result I couldn’t find an image on the other end of the 1000ft cable. So I thought of replacing the line drivers with high-speed line drivers which may fix this problem and on the other hand, thought of using Raspberry pi to process the video from the Openmv UART.

I am planning to use cat5e cable for the transmission purpose.

#4

Hi, I should be able to work on this Tuesday. Packing for a move right now…

#5

You only ever as fast as your slowest link.

Machine vision requires 2 steps busing the data (image) then processing the data. Quite often unless your using parallel (openMV uses 8 bit parallel betweeen camera and processor) the slowest part is the busing of the data not the processing step. I think to bus the whole image data 300m in serial would be super slow. Your will get much better fps if you process the the image on the OpenMV cam to find what your looking for the just then the results over the 300m of serial. i.e if your looking for colour blobs just send the (x,y,w,h) as uint16 x 4 = 8 bytes per blob dectected compared to whole imge :slight_smile: