Two pressure sensors have been tested for our upcoming weather balloon experiment: - Sensor A: Intersema MS5541C, 0..14bar - Sensor B: Intersema MS5540C, 10..1100mbar Both sensors have integrated temperature sensors for temperature compensation. The sensors are factory calibrated with calibration values stored inside the sensors. The software reads out the temperature and calibration values and corrects the raw pressure values accordingly. Two sensor boards were connected to laptop; both boards started simultaneously. Measurement started on 17th floor, then the elevator moved to first floor, up to 25th floor, down to B2, up to 25th and down to 17th. The time in the plots below is not measured in seconds but in a Δt of roughly 1/2s: Interpretation: Sensor A has a relatively large absolute error. Pressure readings are too low (compared to weather report). Error is within the specs of the data sheet. Differential readings of the sensors are quite similar and plausible: 7.5mbar difference between B2 and 25th floor (floors 4,13,14,24 missing!) Results on 17th floor at the beginning and at the end of the measurement differ. This is caused by imperfections in temperature compensation. Possibly the temperature sensor and the pressure sensor do not warm up at the same speed, although they are on the same chip. The “skewed” shape of sensor A’s data is caused by the same effect. Author: Dr. Lampe, Team Selene