Innovative Device Uses Gyroscopes to Measure Earth’s Rotation

A conversation with a flat-earth believer has led to an innovative device that can measure Earth’s rotation using gyroscopes. Developed by Bertrand Selva, this apparatus employs two BMI160 MEMS gyroscopes to detect the planet’s rotation, offering a more compact alternative to traditional methods such as the Foucault pendulum.

The device operates by capitalizing on the gyroscopes’ sensitivity, which can detect angular velocity with a least significant bit of 0.0038 degrees per second. In contrast, the Earth rotates at approximately 0.00416 degrees per second. To extract this subtle signal from background noise, Selva’s design involves taking measurements from the sensors positioned in four different orientations. This approach helps eliminate sensor bias and accounts for gravitational influences.

Before conducting tests, Selva ensured the sensors were aligned with true north. A stepper motor then cycled the sensors through the four positions while a Raspberry Pi Pico recorded 128 measurements at each orientation. The cycle could be repeated up to 200 times, with accuracy improving as more cycles were completed. A Kalman filter was employed to process the raw data, ultimately yielding a result that was within two percent of the actual rotational velocity of the Earth.

Selva noted that the accuracy of the measurements was highly dependent on the alignment with true north, so much so that the device could function as a compass. While this innovative system did not convince Selva’s neighbor of the Earth’s rotation, it remains an impressive demonstration of modern technology’s capabilities.

Beyond Selva’s approach, there are other methods to measure Earth’s rotation, including using gaming technology such as a PlayStation. For those seeking even greater precision, established standards organizations provide rigorous methodologies for these measurements, showcasing the ongoing advancements in our understanding of Earth’s dynamics.