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Some high altitude ballooning missions, projects, and ideas from Northern Ohio.

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Raspberry Pico and I2C

by dbsnyder471, posted in Instrumentation, Projects, RPi

I would like to build a portable weather station for use during the 2024 Total Eclipse, to document temperature and other changes during the few hours of the eclipse, and especially the few minutes of the total eclipse. I have worked on several weather balloon payloads so I have some experience with these types of measurements.
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The immediate goal is to use the Raspberry Pico to read a I2C temperature and pressure sensor.

Humidity And Dew Point Discussion

by dbsnyder471, posted in Balloon, Instrumentation, Projects

I follow Daniels and Alberty [1966] derivation of the Clausius-Clapeyron Equation to determine water vapor saturation pressures, i.e. 100% humidity levels, as a function of temperature. I use this to calculate the Dew Point from temperature and relative humidity, values easily obtained from solid state sensors. Then I look at the Magnus formula, with coefficients suggested by Alduchov and Eskridge [1995] and calculate Dew Points from them. For my initial purposes either approach is good enough, but the Alduchov and Eskridge [1995] approach has a wider accurate temperature range and is intended for high altitude measurements.

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