physics

Principles of motion sensing

Principles of motion sensing is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Principles of motion sensing rather than just read about it. In short: Sensors able to detect three-dimensional motion have been commercially available for several decades and have been used in automobiles, aircraft and ships. However, initial size, power consumption and price had prevented their mass adoption in consumer electronics.

Key takeaways

Principles of motion sensing belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Principles of motion sensing to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Principles of motion sensing from memory before moving on to harder problems.

Reference excerpt

Sensors able to detect three-dimensional motion have been commercially available for several decades and have been used in automobiles, aircraft and ships. However, initial size, power consumption and price had prevented their mass adoption in consumer electronics. While there are other kinds of motion detector technologies available commercially, there are four principle types of motion sensors which are important for motion processing in the consumer electronics market.

Motion sensors

Accelerometers Accelerometers measure linear acceleration and tilt angle. Single- and multi-axis accelerometers detect the combined magnitude and direction of linear, rotational and gravitational acceleration. They can be used to provide limited motion sensing functionality. For example, a device with an accelerometer can detect rotation from vertical to horizontal state in a fixed location. As a result, accelerometers are primarily used for simple motion sensing applications in consumer devices such as changing the screen of a mobile device from portrait to landscape orientation. Apple iPhones and the Nintendo Wii incorporate accelerometers.

Gyroscopes Gyroscopes measure the angular rate of rotational movement about one or more axes. Gyroscopes can measure complex motion accurately in multiple dimensions, tracking the position and rotation of a moving object unlike accelerometers which can only detect the fact that an object has moved or is moving in a particular direction. Further, unlike accelerometers and compasses, gyroscopes are not affected by errors related to external environmental factors such as gravitational and magnetic fields. Hence, gyroscopes greatly enhance the motion sensing capabilities of devices and are used for advanced motion sensing applications in consumer devices such as full gesture and movement detection and simulation in video gaming. The Nintendo Wii MotionPlus accessory and the Nintendo 3DS incorporate gyroscopes.

Compasses Magnetic sensors, commonly referred to as compasses, detect magnetic fields and measure their absolute position relative to Earth's magnetic north and nearby magnetic materials. Information from magnetic sensors can also be used to correct errors from other sensors such as accelerometers. One example of how compass sensors are used in consumer devices is reorienting a displayed map to match up with the general direction a user is facing.

Barometers Pressure sensors, also known as barometers, measure relative and absolute altitude through the analysis of changing atmospheric pressure. Pressure sensors can be used in consumer devices for sports and fitness or location-based applications where information on elevation can be valuable.

Additional An example of an immersive musical experience through motion and gesture is accomplished with a musical infrared harp.

References

Worked examples

Example 1 — a first encounter with Principles of motion sensing

Start with the simplest possible case. Write down what Principles of motion sensing claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Principles of motion sensing before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Principles of motion sensing ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Principles of motion sensing

In research: Principles of motion sensing appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Principles of motion sensing in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Principles of motion sensing is common in secondary-school and first-year university syllabi. It links to neighbouring topics Motion (physics), Sensors, so understanding it makes those chapters shorter.
In everyday life: Look for Principles of motion sensing outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Principles of motion sensing in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Principles of motion sensing means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Principles of motion sensing out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Principles of motion sensing in simple terms?

Why does Principles of motion sensing matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Principles of motion sensing?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Principles of motion sensing.