PART 5 • MEMS ACCELEROMETER DESIGN

The sensor in everything

About 50 million MEMS accelerometers ship every year — in phones, airbags, drones, and game controllers.

📱 💥 🚁

In this part, you'll learn how a structure smaller than a grain of sand turns motion into a measurable electrical signal, and walk through the real design of a commercial accelerometer chip.

Key idea: Every accelerometer is the same basic idea: a mass on a spring, watched very, very closely.

THE BASICS

What is an accelerometer?

An accelerometer is a sensor that measures the change in velocity over time — acceleration.

🎢

They're used in airbags, inertial guidance systems (including missiles), smartphones, and laptops — anywhere a device needs to know how it's moving.

If it needs to sense motion, shock, tilt, or vibration, there's a good chance an accelerometer is involved.

A BRIEF HISTORY

From lab curiosity to every pocket

1979 First MEMS accelerometer, micromachined at Stanford

~20 years later Commercial breakthrough in automotive and avionics

Today Standard component in nearly every smartphone

The Stanford device (Roylance and Angell, "A Batch-Fabricated Silicon Accelerometer") was one of the earliest MEMS products ever made.

IN YOUR POCKET

Accelerometers you've actually used

iPhone 4s

STMicroelectronics 3-axis accelerometer and 3-axis gyroscope.

iPhone 6

An InvenSense 6-axis gyro-accelerometer plus a Bosch BMA280 3-axis accelerometer.

iPhone 13

3-axis gyro and accelerometer, alongside a LiDAR scanner and barometer.

You've been carrying several MEMS accelerometers in your pocket for over a decade.

A MASSIVE, TINY MARKET

Small sensor, big business

~50 million MEMS accelerometers produced per year

$3 – $10 Typical cost per unit

~$10 billion (2018) MEMS accelerometer market size

~$30 billion (2024, projected) Total MEMS market, per Yole Research

A sensor that costs a few dollars, produced by the tens of millions — that's the MEMS business model.

APPLICATIONS

Where accelerometers show up

Automotive

Crash sensing, braking, swerve and roll detection

Navigation

Inertial measurement and object positioning

Medical

Activity sensing for pacemaker control

Industrial

Vibration monitoring on engines and machinery

Structural

Seismic activity sensing in buildings and bridges

Consumer

Tilt sensing, game controllers, and drones

UNIT 17 STUDY COMPLETE

📈

Ready for the Fab Challenge?

You've covered What Are Accelerometers?.