Lab 6: Day 2

The second day we came into the lab we had a better sense of some solutions to our problem. After obtaining the serial port error we were told to completely close Matlab and then reopen it. Surprisingly this solved our problems. From this point forth we could repeatably communicate between the Arduino and Matlab.

Once this communication was established we continued to rig up a low pass filter in a RC circuit. A circuit diagram of our set-up can be seen below. For the given values we determined a cut-off frequency around 169 Hz. Using these values and a sampling time of 1msec we ran a Matlab simulation of what theoretically should happen with the empirical model when we send in random white noise. The following figure shows the expected theoretical results obtained solely in Matlab.

As you can see in the above low-pass bode plot the response tends to taper off near higher frequencies which is what we expect when we send this circuit random noise.

Our next step was to repeat this process using Matlab and the actual RC circuit we built. However, we again began having troubles communicating between the two systems. Serial ports were closed and recognition was of the Arduino was not happening so again we decided that it be best to sleep on it.