Jump Coin

Hold your phone and jump — the accelerometer detects it and chimes

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Hold your phone and jump

Grip your phone firmly and jump in place! The device's accelerometer detects the jump and plays a retro game-style coin chime. The more you jump, the more coins you collect.

Time limit

※ Play in a safe, clear space, grip your phone firmly, and take care not to throw or drop it.

What is Jump Coin?

Jump Coin plays a retro-game coin sound when you physically jump while holding your phone, detected by its motion sensor — a body-moving learning (exercise) app. Unlike games you play by tapping the screen, here you actually have to leap. It works as a state machine tracking the combined acceleration read by the device's motion sensor (DeviceMotion): at rest it's about 9.8 (gravity), when you jump and your body floats it drops toward near-zero in free fall, and the impact of landing spikes it high. From this sink-then-spike waveform it measures your air time and shows an estimated jump height (h = g·t²/8). The more you jump in a row, the more satisfying the sounds, making it perfect for shaking off inactivity on a day you can't play outside, or for a physical change of pace. Only your personal-best air time is saved in localStorage. On iPhone it asks permission to use the sensor at start. On a PC without a sensor, a tap-to-play fallback is provided.

How to play

Open it on a smartphone and tap "Start (allow sensor)".
On iPhone, choose "Allow" when asked for motion sensor access.
Grip your phone firmly with one or both hands (don't drop it!).
In a safe space clear of people and objects, jump in place.
When you land, a coin chime plays and your coin count goes up by one.
Your last jump's estimated height and your personal best are shown.
Keep jumping to collect coins — every 10 coins triggers a confetti celebration.
On PCs and other sensorless devices, use the "Tap for coin sound" button to play.

Great for

Getting kids moving
A sound plays with every jump, so kids stay motivated to keep moving their bodies.
Home workout motivation
Jumps pile up as coins, turning an otherwise monotonous exercise into something fun to keep up.
Counting skips and jumps
It counts jumps automatically, handy for tracking reps of jumping in place or light exercise.
Jump-height contests
It estimates jump height from hang time, so you can compete with friends and family over who jumps highest.
A quick refresh
Stand up and do a few jumps between desk-work sessions for an easy, quick refresh.
Party and event fun
See who can collect the most coins or jump the highest — a fun group activity.

Privacy

Jump Coin runs entirely on your device. Accelerometer readings are used only on-device to detect jumps and are never sent anywhere. The coin sound is synthesized on the fly with the browser's Web Audio feature, so there are no audio files to download and no requests to external servers. The only thing saved is your personal-best jump height, and that lives only in your device's local storage.

FAQ

Q. Is it free to play?: A. Yes, no signup and completely free. There's no usage limit — play as much as you like.
Q. How does it detect jumps?: A. It uses your smartphone's built-in accelerometer. During a jump the device is nearly weightless (free fall), and landing produces a strong impact. Jump Coin reads this characteristic pattern to detect a jump.
Q. I tapped "Allow" on iPhone but nothing happens.: A. On iPhone / iPad, Safari must have motion & gyroscope access enabled. Go to Settings → Safari → "Motion & Orientation Access", turn it on, then reload the page and try again.
Q. Can I play on a PC?: A. Most PCs have no accelerometer, so real jump detection isn't available. In that case use the "Tap for coin sound" button to enjoy the chime. Open it on a smartphone to play with real jumps.
Q. Is the jump height accurate?: A. It's an estimate computed from hang time using basic physics. How you hold the phone and time your landing introduces error, so treat it as a rough, fun ballpark rather than a precise measurement.
Q. There's no sound.: A. Check that your phone's silent/mute switch isn't on and the volume isn't turned down. Sound is enabled when you press the "Start" button, so always begin from that button.
Q. Any safety tips?: A. Grip your phone firmly and play in a safe space clear of people and objects. Take care not to throw or drop the device.
Q. Is any data sent externally?: A. No. Sensor readings and coin-sound generation all happen on your device with no external communication. Only your best height is saved locally.