How can I connect gUSBamp to OpenViBE?

Obtaining data from various hardware devices
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uskeywest
Posts: 2
Joined: Thu Nov 04, 2010 2:54 am

How can I connect gUSBamp to OpenViBE?

Post by uskeywest »

Hello,
I am a beginner for the OpenViBE. I am currently using gUSBamp but having a connection problem. At the openvibe acquisition server, I could choose "gUSBamp" from the Driver and left Connection port just as 1024 (default). However, tie figher or handball demo did not work and command window was showing "VRPN Error, No responses from server for >= 10 seconds".
Please anyone let me know how the gUSBamp can be connected succefully to the openvibe. Many thanks.

Yoon

lbonnet
Site Admin
Posts: 417
Joined: Wed Oct 07, 2009 12:11 pm

Re: How can I connect gUSBamp to OpenViBE?

Post by lbonnet »

Hello Yoon and welcome on board !

To connect you gUSBAmp to OpenViBE, you must:
- plug the amplifier to the PC and turn it on :)
- launch the acquisition server
- Set the acquisition server to "gUSBAmp", the port can remain unchanged (1024)
- Press "connect" to connect the acquisition server to the amplifier then "play" to start reading samples

Then you must check if your device is sending data :
- Launch the OpenViBE Designer
- build a simple scenario with 2 boxes : an acquisition client and a signal display.
- Configure the acquisition client with the address/port of your acquisition server (if the server is running on the same computer, address is localhost)*
- connect the two boxes (Client's "signal" output to Display's "signal" input)
- play the scenario : you should see the raw signal coming from the amplifier

If you need help to use the Designer, you will find useful information on the dedicated section.
Before you try to test more complex applications, such as the tie-fighter scenario, I strongly suggest you to test the OpenViBE designer. Do the tutorials, try some filtering boxes, etc.
It will really help you understand the scenarios we provide : how you read data from files, how you process a signal to compute a band power, how all you may know about signal processing can be done in OpenViBE.

Now if you want to test the tie-fighter application with pre-recorded data, you must :
- Start the application vr-demo-tie-fighter.
- Open the scenario share/openvibe-scenarios/bci/tie-fighter/tie-fighter-freetime.xml
- Play the scenario without changing anything. All the VRPN error messages should stop, as the vrpn connection between the application and the designer is now made.

If you want to test the tie-fighter application in real-time with the gUSBAmp, you will have to edit the scenario we provide, in order to read EEG data not from a file, but from the acquisition server.
- Add an acquisition client box and configure it
- Replace the initial "signal" input/output : the signal stream must come from the acquisition client and not the GDF file reader.
- If you want to have the same instruction flow as previously (10 times "move your feet"/"stop!"), keep the "stimulation" input from the GDF file reader.

It is mostly probable that the application won't work fine at first try, because the configuration of the scenario is highly dependant on the setup (acquisition device used / user's brain activity).
Change the values in the settings of the Crop and Simple DSP boxes in the scenario to lower/turn up the threshold used on the Beta power.

Hope this helps !

Laurent-
Follow us on twitter >> openvibebci

Checkout my (old) blog for some OpenViBE tips & tricks : here !

uskeywest
Posts: 2
Joined: Thu Nov 04, 2010 2:54 am

Re: How can I connect gUSBamp to OpenViBE?

Post by uskeywest »

Thank you so much, Laurent.
Connection was done. Realtime acquisition is nicely working.

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