Innovative Device Uses Gyroscopes to Measure Earth’s Rotation

A conversation with a flat-earth believer has inspired an innovative device that measures the Earth’s rotation using two gyroscopes. Developed by Bertrand Selva, this apparatus simplifies the detection of Earth’s rotation and demonstrates a practical application of gyroscopic technology.

How the Device Works

The device is built around a pair of BMI160 MEMS gyroscopes, which are capable of detecting angular velocity with a minimum significant bit of 0.0038 degrees per second. In comparison, the Earth rotates at approximately 0.00416 degrees per second. To isolate the subtle signal of Earth’s rotation from background noise, Selva’s device employs a clever methodology involving measurements from four different sensor positions. This approach helps to negate sensor bias and the effects of gravity.

Before conducting tests, Selva aligns the sensors toward true north. A stepper motor then cycles the sensors through their four positions. During this process, a Raspberry Pi Pico records 128 measurements at each position. The cycle can repeat up to 200 times, with accuracy improving as the number of cycles increases.

Data processing is accomplished using a Kalman filter, which refines the raw data and extracts the rotational signal. The results showed that the measurements came within two percent of the true rotational velocity. Notably, Selva discovered that the accuracy of the readings was highly dependent on the alignment with true north, to the extent that this device could also function as a compass.

Implications and Broader Applications

While Selva’s device has not convinced his neighbor of the Earth’s rotation, it stands as a significant achievement in the realm of gyroscopic measurement. The simplicity of this design allows for a practical demonstration of scientific principles without the need for bulky equipment, such as a Foucault pendulum.

For those interested in alternative methods, it is worth noting that it’s also possible to measure the Earth’s rotation using a PlayStation. Such innovations highlight the potential for everyday technology to contribute to scientific education and understanding.

As this project illustrates, advancements in technology can provide engaging ways to explore fundamental scientific concepts. Selva’s device not only showcases the ingenuity of using gyroscopic sensors but also opens the door for further exploration into how we measure and understand our planet’s dynamic nature.