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Hello to the Biosemi community,

I have accidentally recorded an epoch in one of my biosemi file (certainly by pausing the actiview). The problem is that I am relying on the absolute time of the recording to synchronize my data (I know that there is a max one second lag as mentioned here: http://www ...

Dear Cohen,

I recently had to synchronize the biosemi with a PC with no specific event or stimuli presented on the PC. For this purpose I made a short program that sends every second a trigger on the parrallel port connected to the Biosemi USB box. Using the following formula I can then compute the ...

Dear Cohen,

I also have a question on the SCR scale. I did import some biosemi bdf data in matlab. But when I check the minimum difference (except 0) between two SCR samples I obtain 0.0321 (although the header indicate nS).

In this case is this safe to consider that my recording/file unit is ...

It seems that adding a buffer did solve the problem. I am now not far from having a python module for Biosemi Actiview acquisition. If you think it can be useful to someone else, I would be happy to give it to you.

I never mentioned that some packets were lost, just that the size of the packets can be different as shown by the sniffer (and the client) I used. I am not trying to accuse you of any mistake I just try to understand why the length of the packet I get are different and if I can still use them. I ...

Thank you for your fast answer Coen, as always,

You will find the result with the Actiview client here:
http://cvml.unige.ch/~chanel/BiosemiToBiosemi.jpg

Yes I was quite sure that the buffer errors came from the fact that the client was not getting the data fast enough (it actually occurs when my ...

Dear all,

I am using the Actiview TCP sever and get the data using sockets implemented in pythons. I am sending over the network the 32 EEG channel + EX1-8 + Aux. In this configuration I obtain a total buffer size of 564 (has written in the Actiview "Bytes in TCP array").

However it sometimes ...

Hello,

I would like to know if it is possible to connect to the actiview TCP server with several clients.

The idea is to have one client taking care of the EEG signals another of the GSR etc...

If not do you have any cues about possible actiview modifications to handle that ?

Guillaume

Thanks Coen,

here is a small pseudo code for the packet processing, please confirm that this is correct and hopefully you will avoid anymore question on the topic :)


packets = read packet from socket
for all packet of 3 bytes p in packets
-- strValue = p // this string code for a sample of a ...

Hi,

I think I read all the messages from the forum concerning the TCP packet format but I am still not able to make my own client (needed to create an one line application).

So if I understood correctly the data sent over TCP is in the same format as the BDF files. I can see from the BDF format ...

Hello,

we plan to record online two participant with one biosemi system. One paticipant using EMG recordings and the other using EEG recording. The main question we have is the question of references.

Is it possible to use both references (EEG CMS&DRL and front panel CMS&DRL) at the same time for ...

Hello,

I am really new at labview but I hope I will find some answers here. I would like to acquire data online using the Biosemi Active 2 System Mk1. To do this I used the ligth version of actiview as it was proposed earlier on this forum. For the moment I am able to retrieve a single sensor and ...

Hi,

I'm coming to you because of a problem I encountered 2 times
during my EEG acquisition step. I use a seelf-modified version of the
acti-view sofware to get some trigger from another software (wich is not the best to obtain accurate timing but at leat it works). Until now
everything was ...

Maybe you can read them record by record or let's say 20 records by 20 records insted of the whole file at a time. This is a bit harder to handle but this is the only way I found to read large BDF files.

Moreover keep in mind that there is the matlab file to read BDF files on the Biosemi website ...

Hi,

I'm using the biosemi system abroad (not in switzerland but in croatia) for the first time and I have some problems charging the batteries.

I connected the charger to the battery (DC output to charge output) and to the power line using the classical adapter of Biosemi. But none of the ligths ...

Hi,

I'm working on the Biosemi BDF files and I'd like to know how many
samples there is in a BDF record. I found that there is 1024 for the files
I recorded from the Biosemi software. Is it a fixed number or is it linked to
the sampling frequency ? Can I find this information in the file ?

thanks ...

Hello,

I'm currently using a Biosemi Active 2 device with GSR external captors
provided by Biosemi.

With this, I can record two signals GSR1 and GSR2. I'd like to know the
difference between these two signals. Usually(depending on the
subject) , only GSR1 seems to contain interesting information ...