1 Topic by philtrick123

  • philtrick123
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Hi,

I'm working with a golf launch monitor manufacturer and i want to request they include a UDP trigger when the ball is struck. Are there any details of how this works.
On a side note is there a way of sending a UDP trigger from a different computer on the same LAN. i.e. one computer has Kinovea running, the other computer a 'button' to send the UDP trigger.

2 Reply by joan

  • joan
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Details: when you click on Enable UDP trigger in the preferences it will start listening on the UDP port configured. (You still need to "arm" the trigger as for audio in the capture screen (lightning icon)).

The UDP message itself is ignored, you can send an empty string.

It works from different computers. I just double checked by installing an app called "UDP Sender / Receiver" on my mobile phone and I was able to trigger the capture remotely. (In this case it insisted on sending a message so I just set it to "a").

Here is a small python script sending a packet every 10 seconds. You can send to the IP of the computer with Kinovea. If you don't know it you can send to 255.255.255.255.

import os
import socket
import time

# Send an empty udp broadcast every 10 seconds.
def broadcast():
    print(f'Broadcasting at {time.ctime()}')
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
    s.sendto(b'', ('192.168.0.228', 8875))
    s.close()


if __name__ == '__main__':
    while True:
        broadcast()
        time.sleep(10)

3 Reply by philtrick123

  • philtrick123
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Thanks Joan!!!

4 Reply by impeccable (edited by impeccable Yesterday 03:11:07)

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Hi, that’s an interesting use case! A UDP trigger is usually just a simple packet sent to a specific IP/port when an event happens (in your case, ball impact). The device or software listening on that port can then react immediately. It’s lightweight and fast, which is why it’s often used for this kind of real-time triggering. fnaf


For your second question, yes, you can definitely send a UDP trigger from another computer on the same LAN. You could set up a small script (Python, for example) or even use simple tools that send UDP packets on button press. As long as both machines are on the same network and you know the target IP/port, it should work fine.

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