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Hi.

I’m ali and I use LabVIEW 7.1. I had a problem with my webcam. I wrote a program and I use a DLL (capwind.dll) that can read out the webcam that connected to the computer. It has some functions to do this. But the problem is here that if there isn’t any webcam connected to the computer it can’t recognize it and it open the USB port and then hangs and do nothing. How can I detect the devices especially webcams that connected to the computer in LabVIEW? and after that select my webcam.

Thanks a lot.

Ali mootab.

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Message 1 of 15
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I don't know your dll, but have you checked if inside your dll there is a function to find out?

Another way would be to look into the registry, I'm shure an answer is buried in there if you have the key ...

 

Greetings from Germany
Henrik

LV since v3.1

“ground” is a convenient fantasy

'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'


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hi. thanks for your answer. i found a new dll (webcamgrab.dll). it has a function (Get Digitizers) that returns the number of webcams that are connected to the PC USB port.

To install the webcam library, follow the steps given below:

 

1. Extract all of the files from the compressed zip archive to your LabVIEW user.lib folder.

2. Run LabVIEW.

3. Open the user submenu of the function palette for the webcam library functions.

 
but the problem is here when i use that function it always returns 'Microsoft WDM' string. i don't know why?
that is so nice of you to help me.
 
Ali S.Mootab
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Message 3 of 15
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Hello Ali,

Henry makes a good point - try checking the registry keys under your product before AND after connecting the webcam, and search for differences bestween the two. Another possibility is if your device has a command which you can write to it, which causes it to return data to you, you can write that command at the beginning of your application, and if you don't get a response within a certain amout of time, you'll be able to assume that the camera is not connected.

For further question regarding your specific dll, you may want to contact the author of that dll.

Hope this helps. 

AG

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Hi Ali,

I tried the steps you mentioned about running the digitizer.vi, but the only thing i get is 'Microsoft WDM'. How did you solve this problem? How did you get the webcamera running?

Thank you .


Mozill
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Mozill:

What is your OS? I have seen this error occur with older Operating Systems. Please let me know.

Thanks,

Rudi N.

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Hi Rudy,

I am working on Windows XP home edition.

Thank you for your time.

Regards,

Mozill
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Message 7 of 15
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Mozill:

I followed all the steps highlighted by Ali and after running "webcam Get Digitizers.vi", I did not get any errors. At what point of the process do you get the 'Microsoft WDM' message?

Thanks,

Rudi N.

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Hi Rudy,

Its not a message. On the front panel, there is a control to change the device number and it will show the corresponding string as 'Microsoft WDM' at digitizer ID of 1. It doesnt show any string at any other number.

Thank you for your time.

Regards,

Mozill
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Message 9 of 15
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Mozill:

Is your camera properly recognized by your OS?. If your camera is properly working outside of LabVIEW, it will then be safe to assume that the issue with the way the driver is interfacing with the camera. At this point, I may have to locate a USB camera to replicate all this on my end. Please let me know what you find.

Regards,

Rudi N.

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