Neuronal Unit Impulse Recorder

Jen Lee

My project was to create a VI that acts as a unit impulse recorder to replace the Plexon software used in Wightmann labs. My advisor was Collin McKinney, and he clarified all of the specifications of the VI that I should accomplish. My VI was to take an input signal, detect all of the zero crossings with a positive slope, cut out these zero crossings with a few samples before and after the crossing, send these signals to be processed through acceptance boxes, and have the acceptable waves plotted on a final graph. The final graph and initial triggered signal graph were to be cleared at a specified time limit (my default is 10 seconds). The VI was also to be in as close to real time as possible. As far as generating the VI, I was pretty much on my own and had the help of my classmates for insight into certain problems. The use of Express VIs helped me greatly when performing the zero cross detection and acceptance parameters. Most of the Express VIs used samples as their parameters, so I had to convert the user inputs (which are prompted to be in seconds) and turn it into samples. Local variables were key in this project, as were initializing and clearing arrays in order to get the waveforms to plot on top of one another as well as clear when needed. I had the hardest time trying to figure out how to get the waveforms to plot on top of one another, however using arrays, local variables, and case structures, the task was completed.

This project was a worthwhile endeavor for it made me use a lot of techniques in LabVIEW that I have not used very often in my previous homework. I initially tested my VI using a built in function generator in the actual VI, however I switched to a DAQ and function generator in order to finalize the testing on my VI. I did not really work too much in the lab that my project was assigned to since my project is more signal processing than having to do with anything in the actual lab. However, I feel that it all worked out for the better. Below are screen shots of my front panel, and several aspects of my block diagram.