BioSemi.nl

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 plot it on a separate graph (the one I am interested in is the Plethysmograph sensor). Every thing is fine exept that I would like to have many samples of this channel to perform some computation on the signal using matlab (computing heart rate). To do this I need at least 3 seconds of signal to be sure to have two heart beat in it. How can I do that :

- should I add another buffer to wait for the data samples (how to do it in labview ?)
- can I configure the ActiView ring buffer to perform this task and how ?

Thank you very much for your answer,

Guillaume Chanel

Both approaches are possible.

- Example of defining a new buffer can be found in the full standard version of ActiView. A (double) buffer is used to store the 1 second blocks saved to the BDF file, and another buffer is used to calculate the online average (ERP).
- Instead of reading small blocks of data (with a lengths of "display step), you can just read the last 3 seconds of data from the ringbuffer and process it.

Best regards, Coen (BioSemi)