How IMUs Work

Owned by Hardy Yu
Last updated: 2024-01-28
2 min read

This page will be focused on explaining how each of the components on IMU works, disenchanting these delicate electronics.

Accelerometer:

Basic Idea

  • You can imagine the internal of an accelerometer to be two pieces of conductive metals attached to springs while leaving a dielectric gap between them.

  • The combination of two metallic plates leaves a dielectric gap that forms a classic capacitor100%

Untitled-20240128-154020.png

  • With the area A and permittivity ϵ known, capacitance C measured, we could calculate the distance between the plates d

  • Since the plates are attached to a spring, we can know the force F applied to the spring by formula F = k (Δd)

  • By Newton’s second law, F = ma, the acceleration of the object is calculated

In Reality

Untitled (1)-20240128-160930.png

  • There are multiple metallic beams (shown in green), and a big moveable metal in all three directions (shown in red) that is attached to springs

  • This design allows the measurement of the capacitances on three axes to happen at once

 

Gyroscope (wip)

 

How the Gyro Sensor Works

 

Gyro shootout: MPU6000 vs ICM20602 vs BMI270 and OSR4 mode for BMI Gyros!

 

Magnetometer (wip)

How Magnetometer Works - Animation || The Hall Effect & Lorentz Force

References:

9-Axis IMU LESSON 3: Understanding How Accelerometers Work