Inventor Uses Gyroscopes to Measure Earth’s Rotation

A new device developed by inventor Bertrand Selva successfully measures the Earth’s rotation using a pair of gyroscopes. This innovative approach provides a compact alternative to traditional methods, such as the Foucault pendulum, while delivering surprisingly accurate results.

Selva constructed his apparatus around two BMI160 MEMS gyroscopes. These sensors are capable of detecting angular velocity with a precision of 0.0038 degrees per second, while the Earth rotates at approximately 0.00416 degrees per second. To isolate this subtle signal from surrounding noise, the device takes measurements with the sensors positioned in four orientations, effectively eliminating sensor bias and the influence of the gravitational field.

Before initiating each test, Selva aligned the sensors toward true north. A stepper motor then cycled the sensors through the four positions, with a Raspberry Pi Pico recording 128 measurements at each orientation. The device could perform this cycle up to 200 times, with the accuracy improving as the number of cycles increased. A Kalman filter processed the raw data, extracting the rotational signal within two percent of the true value.

The alignment of the system proved crucial for accuracy. Selva noted that even minor misalignment could significantly affect the results, to the extent that he could use the system as a compass. While the demonstration did not convince a local flat-earth believer of the Earth’s rotation, it stands as an impressive showcase of modern technology’s potential to explore fundamental scientific principles.

This gyroscopic approach to measuring Earth’s rotation is straightforward, yet it illustrates a fascinating intersection of physics and engineering. For even higher precision in rotational measurements, various standards organizations employ advanced methods and technologies. Selva’s work not only challenges unconventional beliefs but also highlights the capabilities of modern instrumentation in understanding our planet’s movement.