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vaping in the laboratory
Wednesday, March 25 2015
Today, after battling an unreliable solder connection of the I2C SCL line, I found the source of my data skew issue. It turns out that every BMP180 sensor has a set of calibration constants that vary from one sensor to the next. My test code (for now known as "gusweather.ino") is a modification of some code posted on SparkFun.com, and I'd failed to note a function call designed to populate some global variables with those calibration constants. So I was only getting the constants for barometer #0 and using them for all the sensors. The skewed data for non-zero barometers was exactly what one would predict. The fix was a simple matter of putting the calibration function immediately after the code to set the address of the sensor.
The forecast called for gradually warming temperatures and rain, but when the rain started falling it came as sleet. Since the temperatures at the time were in the mid-40s (Fahrenheit), it suggested the "rain" was falling from a considerable height. It wasn't a particularly pleasant day, but for the first time this morning I'd seen geese in migratory formations flying northward.
This evening one of my friends came over with his brand new $125 vaporizer (bought on Craigslist purportedly for an elderly cancer patient who then died) and we spent a couple hours drinking beers, listening to music, and vaping marijuana in the laboratory. The Kills on my streaming radio station ("Bagel Radio") reminded my friend of The Raveonettes, so I played the only album of theirs I really like: "Whip it On." From there, the music moved on through the playlist I've had for the past week or so: first Screaming Females and then vintage Judas Priest. After sleuthing out my barometric data skew problem, I was in a celebratory mood. Gretchen was too; she'd just learned that one of her poems was to be presented in very prestigious circumstances. But her chosen method of celebration was television police procedurals and flat champagne from a previously-opened bottle that had been languishing in our refrigerator.
For linking purposes this article's URL is:
http://asecular.com/blog.php?150325 feedback
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