It's Input Origins time! our monthly dive into the creative ways we’ve interacted with machines. This month: how a bomber-guiding sensor became the brains behind your game controller.
Meet the IMU, short for Inertial Measurement Unit. If you’ve ever turned your phone to tilt your screen or swung a Wii remote, you’ve already used one.
Let’s rewind.
[The Apollo program's IMU that guided astronauts through space]
So, What Is an IMU Really?
Think of it as a digital inner ear. An IMU combines accelerometers to sense movement and gyroscopes to sense rotation. Together, they tell a device which way it’s moving, turning, or tilting, no GPS needed. That’s how your phone knows it flipped, or your controller knows it swung.
[The 1953 SPIRE - IMU]
Back To 1953
The IMU was born in 1953 at MIT’s Draper Lab to solve one challenge: guide a plane without external signals. Their solution, SPIRE, used gyroscopes and accelerometers to track motion internally. It flew coast to coast in a B-29 with no external guidance. That breakthrough later guided Apollo to the Moon. Today, the same principle powers the motion sensors in your phone.
[The 2009 Nintendo Wii MotionPlus Controller]
Wii Remember: When IMUs Went Mainstream
By the 1990s, IMUs left the skies and entered the mainstream, first in military VR simulators, then in living rooms. The real game-changer? Nintendo’s 2009 MotionPlus packed a full 6-axis IMU into a controller. Suddenly, tilting a sword or steering a kart wasn’t just a game mechanic, it was your movement, digitized.
That leap was driven by MEMS, a technology that let engineers build IMUs directly into silicon chips. What was once the size of a briefcase could now sit on your fingertip. Shrinking the IMU unlocked everything, from motion-controlled games to smartphones that know when you flip them, and wearables that follow your gestures.
As IMUs got smaller and smarter, they stopped just tracking motion, they started controlling it. Shake to skip a song. Tilt to steer. Rotate to scroll. From phones to fitness bands, drones to smart rings, the IMU became the invisible joystick for the modern world.
Without IMUs, There Is No VR
Today, IMUs are quietly running the show behind the scenes of VR and XR. Every time you move your head in a headset or wave a controller in space, an IMU is tracking your motion in real time. It's how your view tilts as you lean, how your virtual hands mimic your real ones, and how body tracking systems follow your limbs with uncanny accuracy.
They're in Meta’s Quest controllers, Sony’s Mocopi body trackers, and the wristbands powering hands-free interfaces. Combined with clever algorithms, IMUs turn physical motion into spatial commands, swipe, aim, grab, all without ever touching a screen.
[AR glasses meet Mudra Link]
Where IMUs End, Neural Signals Begin
IMUs are brilliant at what they do: tracking motion through space. They know your orientation, speed, and direction. But they don’t know your intention. They can’t detect a subtle pinch or fingertip pressure gradations. They only see the body once it’s already in motion.
That’s the ceiling for IMU-based input. And that’s where neural sensing take over.
Using the Mudra surface EMG, we can detect the electrical signals your brain sends to your hand before the motion even happens. That means we’re not just tracking movement, we’re reading intent. Want to isolate individual fingers? Detect pressure levels? Detect gestures without visible motion? Neural input makes that possible.
That’s why Mudra Link fuses both. IMU for spatial context. sEMG for neural precision.
Together, they don’t just track what you’re doing, they understand what you’re trying to do.
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