Archive for October, 2009
David’s Robot Pumpkin（石頭的南瓜機器人）
David saw the LED kit at the Evil Mad Scientist Laboratories about a month ago and that gave him the idea of a robot pumpkin for the Halloween (萬聖節). Even though his Robot Pumpkin looked very cute during the day (but not as cute as my baby pumpkin), it actually looked pretty scary in the yard at night! But apparently not scary enough for those little trick-or-treaters.
We got about 8 kids dressed in all sorts of different cute customs; too bad that my camera didn’t work that well to catch them. Our last visitor was an adorable 2-year-old Elvis. He looked rather confused and didn’t realize that he got a role to play, so instead of questioning, “Trick or treat?“, he extended his tiny left hand, looked at me, and asked frankly, “Give me candies.” David, I, and his young parents next to him all burst out laughing! What was I supposed to do besides following his cute demand? 
My baby pumpkin, David's Robot Pumpkin, and David
4 comments October 31, 2009
David’s New Pet（石頭的新寵物）
Come see David’s new pet — The Evil Domo Santa! Today as we walked by the window display of Kingston Bookstore, this little monster grabbed David’s attention and he immediately fell in love with it. At first I thought that he was getting it for his little buddy, JC, but no no no, it was for himself! How cute! So I said, “Nah, I’ll get it for you as your Xmas present. Merry Xmas!”
The Domo Santa is scary in a very cute way and fits perfectly with the Halloween spirits. See how protective it is of David? I can almost hear it barks, “Go away! David is working! Or I’m gonna bite you!“
1 comment October 28, 2009
Can You See Me Now?
Today I cleaned up my scripts and set up the data storage structure (to get ready for decades of solar power data! ). I’m sure that I’ll wanna tweak our daily output later as I learn more about R graphics, but as for now, I’m happy enough with them and want to work on my long To-do list first. Plenty of Python/R/shell scripts to write in the future! 
And once I’m happy enough with the daily and weekly data analysis (I’ll add the monthly and annual ones later on), David will setup the cron jobs to fully automatically produce graphs and data daily/weekly/monthly/annually. Pretty neat, huh?
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It turns out that our solar system is an amateur weatherman, too. Even though it couldn’t tell us that today was a windy day, it did show us that it was cloudy around noon.
The sun: Can you see me now? Last Sunday evening, it even recorded the power outage as well (and dropped the daily total power statistics as a result). |
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The pair plotting graph looks cute, but the most important one is the Power vs Time graph as shown above. I might drop this eventually when its cuteness wears out. |
From the summary statistics, we learned that our power system was happier than yesterday even though it was cloudy around noon. What does that tell us? To get the full picture about the daily power generation, we really need both the graph and the summary.
1 comment October 27, 2009
A Beautiful Mind
Continue our Solar Power Adventure…
Last week David spent his vacation writing a C software package called fslurp at SourceForge, to “read and display data from Fronius IG and IG Plus inverters, using a serial port to talk with the Fronius Interface Easy Card.” Because now we have a way to read our inverter’s beautiful mind, it’s time to start collecting data and do something about it!
First I wrote a tiny Python script to clean up the dataset generated by David’s fslurp. Next I loaded the cleaned dataset to R for the data visualization step. 
However, things didn’t go as well as I had in mind; the plotted graph looked strange — each reading was a short horizontal line instead of a circle.
After investigating the problem for a while, I realized that I got tripped over by the infamous Factor object. Fortunately, plenty of experienced R users have already solved this problem and posted their solutions along with detailed explanations online. Even better, William Revelle actually implemented the same solar power plotting project back in Feb. 2006! While he had 38 months of data, I just had 1 day to play with. But, still!
Tomorrow I’ll need to add a little shell script to have the whole process automatically run at the end of the day. Frankly, it’s more interesting to have at least 1 year of data, so we can see the amount of power generated following the changes of season. But we’ll get there, and we’ll have a lot more data to track!
[10/27/2009 UPDATE] Yesterday I forgot to post the daily summary:
3 comments October 26, 2009
