A conversation with a flat-earth believer led to a remarkable innovation by Bertrand Selva, who developed a device that employs two gyroscopes to measure the Earth’s rotation. This gadget offers an alternative to the traditional Foucault pendulum, demonstrating the planet’s movement with a level of accuracy that is both practical and efficient.
Technical Breakthrough in Gyroscope Technology
Selva’s apparatus is based on a pair of BMI160 MEMS gyroscopes, which can detect angular velocity with a least significant bit of 0.0038 degrees per second. In comparison, the Earth rotates at approximately 0.00416 degrees per second. The challenge was to isolate such a small signal from the considerable noise present in the measurements.
To achieve this, Selva positioned the sensors in four different orientations to eliminate sensor bias and the effects of gravitational influence. Before conducting any tests, he carefully aligned the sensors to true north. A stepper motor then cycled the sensors through the four positions, while a Raspberry Pi Pico recorded 128 measurements at each position. The testing process could be repeated up to 200 times, with error margins decreasing as the number of cycles increased.
Data Processing and Results
The raw data collected from the sensors underwent processing using a Kalman filter, which effectively extracted the signal related to the Earth’s rotation. Selva discovered that his measurements came within two percent of the true rotational velocity, a significant achievement considering the simplicity of the system.
The accuracy of the readings was notably influenced by the alignment of the device. The effect was so pronounced that Selva found he could use the system as a compass, further showcasing its potential utility.
Although the device did not succeed in convincing Selva’s neighbor of the Earth’s rotation, it stands as an impressive demonstration of scientific innovation. Selva’s work illustrates how unconventional discussions can lead to groundbreaking advancements in technology.
For those interested in exploring alternative methods for measuring the Earth’s rotation, Selva’s device offers a simpler approach. Additionally, there are even more precise techniques utilized by standards organizations to ensure accurate measurements of our planet’s movements.
