9-axis compass module CJMCU-MPU9150

Jargon buster

Plain-language definitions for the technical terms used above.

breakout

A breakout board carries a small or fine-pitched component and brings its connections out to standard, breadboard- and header-friendly pins. Describing a part as a breakout means it can be wired into a project without soldering directly to the component's tiny contacts.

Gyroscope

A gyroscope measures rotation, such as how fast a board is turning around its X, Y, and Z axes. This matters for projects like gesture controls, balancing robots, and motion tracking where tilt or rotation changes need to be detected.

Headers

Rows of connector contacts on a fixed pitch (commonly 2.54 mm) used to link a board to a breadboard, jumper wires, or another board. They come as male pin headers and female socket headers; when a module ships with pre-soldered headers it can be used straight away, whereas bare pads require soldering the pins yourself.

I2C

I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.

IMU

An IMU (Inertial Measurement Unit) combines motion sensors, typically an accelerometer and gyroscope and sometimes a magnetometer, to measure movement and orientation. It can sense motion, tilt, vibration, rotation, and changes in direction, which is useful for tasks such as navigation, stabilisation, gesture detection, and asset tracking.

magnetometer

A sensor that measures magnetic fields, often used to work out compass direction. It matters because nearby magnets, motors, or metal objects can affect readings and may require calibration.

microcontroller

A microcontroller is a small computer on a single chip that runs a stored program and controls connected inputs and outputs such as buttons, sensors, displays and communication interfaces. In a device built around one, it is the part that executes the code and coordinates the device's behaviour.

MPU

MPU can refer to a few different things in electronics: a microprocessor unit (a processor powerful enough to run a full operating system such as Linux, with external memory and storage), a motion-processing unit like the MPU-6050 or MPU-9250 inertial sensor modules, or a memory protection unit built into some microcontrollers. The intended meaning depends on the surrounding context.

MPU-6050

A combined motion-sensing chip that includes a 3-axis accelerometer and a 3-axis gyroscope. The exact chip name matters because it determines the available ranges, data format, and example code or libraries you can use.