Send picture with Wifi shield

AlfonsoAIT · February 24, 2021, 12:38pm

Hello,
I have an OpenMV Cam H7 Plus with a Wifi shield and need to send a picture to another device connected to the same LAN.
Is there any way to do it?
Regards

kwagyeman · February 24, 2021, 3:42pm

Yes, using sockets. You kinda have to write the protocol yourself.

AlfonsoAIT · February 25, 2021, 12:09pm

Hello again,
How about writing directly a file with the picture on the other device via ftp?
The other device is a portable device (HMI display/PLC) running Windows Embedded 7.
If it is viable, do you have any code example?
Regards

kwagyeman · February 27, 2021, 7:43pm

You’d have to write it via sockets right now. We don’t have high level protocol stuff yet.

AlfonsoAIT · September 19, 2023, 6:59am

Hi again,
Some time ago I understood that you planned to write a ftp protocol in future.
Is it already available?

kwagyeman · September 19, 2023, 6:56pm

Nope! We did make a very nice RTSP video streamer.

Also, urequests works well. So, you can do rest API stuff.

AlfonsoAIT · September 20, 2023, 3:04pm

Hi again,
What we really want is to analyze a product on a machine and send to the PLC some result data and the picture. We need to do that in about 600 ms max.
We manage to send the data via sockets and the pictures via streaming, but we don’t see how to do both at the same time.
Sending the picture via socket would do, but it is too slow.
We are now testing with the new RT cam.
Any idea?
Thanks

kwagyeman · September 20, 2023, 5:35pm

Sending the picture via socket would do, but it is too slow.

Uh, it shouldn’t be. Streaming is just sending via sockets. It’s the same. Here’s the RSTP code:

github.com

openmv/openmv/blob/master/scripts/libraries/rtsp.py

# This file is part of the OpenMV project.
#
# Copyright (c) 2013-2023 Ibrahim Abdelkader <iabdalkader@openmv.io>
# Copyright (c) 2013-2023 Kwabena W. Agyeman <kwagyeman@openmv.io>
#
# This work is licensed under the MIT license, see the file LICENSE for details.

import errno
import random
import re
import socket
import struct
import time


class rtsp_server:
    def __valid_tcp_socket(self):  # private
        if self.__tcp__socket is None:
            try:
                s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

This file has been truncated. show original

…

The easiest thing to do would just be to use the urequest library and just have your PLC be a server and send data to it via that.

…

Anyway, see the https://github.com/openmv/openmv/blob/master/scripts/libraries/rtsp.py#L296 send function for how to send data fast.

kwagyeman · September 20, 2023, 5:37pm

Note, for the urequest library you can do the multi-part file header to send the jpeg image:

github.com

openmv/openmv/blob/master/scripts/libraries/urequests.py#L81


      
                  try:
                      recv = s.recv(1)
                  except:
                      pass
                  if len(recv) == 0:
                      break
                  buf += recv
              return buf
          
          
          def request(method, url, data=None, json=None, files=None, headers={}, auth=None, stream=None):
              try:
                  proto, dummy, host, path = url.split("/", 3)
              except ValueError:
                  proto, dummy, host = url.split("/", 2)
                  path = ""
              if proto == "http:":
                  port = 80
              elif proto == "https:":
                  import ussl

Topic		Replies	Views
how to transfer the image from openMV to PC in real time? OpenMV Boards	12	3642	October 1, 2021
Continously send images to pc OpenMV Boards	3	3016	August 22, 2023
how to send image to server by post to http? OpenMV Boards	63	17552	June 28, 2021
Having issue with WiFi connectivity OpenMV Boards	5	1051	June 13, 2020
Uploading files using WiFi shield OpenMV Boards	3	165	April 13, 2024

Send picture with Wifi shield

Related topics