We measure the vertical velocities of elevators, pedestrians climbing stairs, and drones (flying
unmanned aerial vehicles), by means of smartphone pressure sensors. The barometric pressure obtained
with the smartphone is related to the altitude of the device via the hydrostatic approximation. From
the altitude values, vertical velocities are derived. The approximation considered is valid in the
first hundred meters of the inner layers of the atmosphere. In addition to pressure, acceleration
values were also recorded using the built-in accelerometer. Numerical integration was performed,
obtaining both vertical velocity and altitude. We show that data obtained using the pressure sensor
is significantly less noisy than that obtained using the accelerometer. Error accumulation is also
evident in the numerical integration of the acceleration values. In the proposed experiments, the
pressure sensor also outperforms GPS, because this sensor does not receive satellite signals indoors
an…