OpenViBE forum

Hello, I worked with an arduino board for its digital outputs, maybe I can help you. I am not sure to understand what you want to do : do you want to acquire data from the arduino board in an openvibe-driver ? If yes, did you already program the arduino board so that it acquires data and send them t...

Hello Jozef,

I think it will not be a problem for the measure, as I already deactivate the drift correction (to treat all data as fast as possible when they are received) and I use just one machine.

Regards,
Amélie

It is an important aspect of my delay problem, but as I am using simple scenario with few boxes, the delay seems to be introduced mainly by the "acquisition" part (the order of magnitude is 2 to 12 ms for scenario/effector activation, 30 to 60 ms for acquisition server->client). I would like to test...

Hello, thank you both for this instructive discussion ! I will try to reduce the delay at different levels, and see if it is enough for my use, even with acquisition server's buffering. Drift correction is Ok, I noticed immediately that it makes delay vary much more :) I can certainly spare time in ...

Hello, I tried with lower block-size, but unfortunately one of my acquisition devices doesn't allow a real-time processing under 32 samples per block. I noticed that the delay is lower and less variable when deactivating all network connections, anti-virus etc. If you don't need to run the acquisiti...

Hello all, I want to measure the treatment time of a BCI loop using OpenViBE and different acquisition systems and drivers, to evaluate the delay between the user's decision and the result (display or effector activation). If necessary, I want to identify which steps take a long or variable time. To...

Hello all, a new question about a choice in Openvibe acquisition server : why is the sampling frequency an integer ? Why not a float32 for example ? Some acquisition devices can propose non-integer sampling frequencies, so a drift is introduced (but the drift correction manages this well). Best rega...

I found it was a strange choice, now I understand.

Thank You Yann !

Hello Jozef

I agree with you, it's great that the designer allows double precision. But my acquisition device also provides double precision data, and this precision is lost in the driver, which requires simple precision data. This is what I do not understand.

Best regards,
Amélie

Hello, I am developping a driver and I just encountered something curious : in the Designer, the type of signal samples is float64, so I though no precision would be lost if the driver acquires double precision data. But in the driver, the buffer that has to be filled with these samples and sent to ...

It is the format of the files generated by the Biomea acquisition system that we use.
Indeed, the only software I know to read this format is provided by Cambridge Electronic Design (Spike2). But I don't know much more about it

Amélie

Hi Laurent,

it was simple and my box works now perfectly.
I did not think these informations would be available at initialization (I wondered when the signal-stream header was receive exactly).

Thank you very much !
Amélie

Hello all, I am writing a box whose task is to write a signal from the acquisition client (eventually with some known modifications) and other information channels (text marks) in an smr file. Is it possible to get informations on the signal (channels number, sampling rate ...) when initializing the...