This is a system for a simple and easy baseline calibration of team pHFine scale's pH sensor for generalized medium accuracy environments. In the blue tank, an artificial seawater solution (8.05 pH) is mixed. It is then distributed to the smaller yellow and purple tanks, with the help of pumps (shown in brown) where it is mixed with hydrochloric acid, and sodium hydroxide to create a relatively acidic solution (7.10 pH) and a relatively basic solution (9.20 pH), respectively. Each of these three solutions are pumped into the orange tank, where they are thoroughly equilibrated with atmospheric carbon dioxide in a closed system and have their pH and temperature measured to extreme precision with a colorimetric pH sensor, and team pHFine Scale's glass electrode sensor. Each solution is drained after measurement into the green container. The process is then repeated, with the temperatures raised a few degrees by internal inductive heaters, for temperature compensation. The colorimetric sensor uploads its data to the glass electrode sensor, to give it a basis for calibration. A Bluetooth transmitter (the black box) logs the data to a smartphone, which then uploads it to a data logging server.
Designed by Ethan Kurteff, with assistance from Jack Maughan, Benek Robertson. Special thanks to our MBARI mentor, and Carmel High School Robotics Team 2035. We would like to thank Mr. Guardino, our rockstar chemistry teacher. In addition, thanks to TinkerCAD for providing very intuitive (and free) CAD software.