Two months ago I wrote a blog post documenting my first OSBSS build of our low power (long battery life) air temperature and relative humidity data logger. At that time we were using the SHT15 sensor breakout board to measure both temperature and relative humidity. After some co-location tests with Onset HOBO data loggers and others, we discovered that (a) yes we could achieve low power draw and long battery life on this base framework of a data logger, (b) yes we could achieve accurate relative humidity readings compared to a HOBO, but (c) unfortunately, our temperature readings were not very accurate (they were decent after calibration, but who wants to build a temperature sensor that then has to be calibrated against another, better temperature sensor!?). This last part really bugged us — we simply couldn’t rely on the SHT15 to provide accurate temperature measurements, which then, because RH is based on temperature readings, yielded both inaccurate T and RH readings.
