The solar cell lab we did last week asked us to measure the voltage output of the solar cell, and the light intensity output of the light sensor of the NXT. We started out by plugging in the the light source, then we had to connect the NXT to the battery and light source with a 2 sided wire.  The last step was to connect a usb cord from the battery to the computer so labview could give us all of our data.

We first started out by making the room as dark as possible, then reading the NXT without the light source on it.  This gave us a starting point on what to base our other calculations on.  The next step was to put a light source on the NXT at a few different distances.  We chose to measure the NXT distances of .5, 2, 3, and 5 inches away from the light source.  What we noticed was that the farther the NXT was away from the light source, the average voltage output decreased significantly.  The average voltage output with no light was about .07 and followed the distances with .60, .44, .39, and .30.  As you can see, there was almost no voltage output when there was no light on the NXT.  However, when light is applied, the average voltage more than tripled each time.

The next step was to shine light on a few colored film filters.  We kept the light 2 inches away from the filters so we could see how each color was affected.  Again, we averaged the voltage output of each color.  The primary blue film averaged a .45 voltage output whereas the iris purple film averaged .475 volts, followed by the yellow film averaging a .48 voltage.  These measurements told me that the film with the darkest color had the lowest average voltage output.  The blue film had the highest voltage output because it was a dark blue, followed by a lighter shade of purple, and ended with yellow which is not as dark of a color as blue or purple.

Overall, I thought it was a great lab to try and understand how the voltage output and light intensity output relate.  We noticed a pattern that the higher the light intensity output, the higher the average voltage output was.  In other words, the closer the light was to the NXT (or more light the NXT received), the voltage output would increase.  However, I noticed the average voltage output barely changed when the light was 2 inches away from the NXT, even with the colored films.  With just the light, the average voltage was .44, while the blue film was a .45 voltage, purple film a .475, and yellow film a .48.  This raises a question in our findings unless the films are not supposed to change the voltage by much.  In the end, I am confident with our measurements, and now understand the relationship between voltage output and light intensity output.