ArmSound

Every arm motion gets its own sound. A gunshot for a finger gun, a slash for a downswing, cheering for a wave. Three samples are included — try them, then add your own.

Swing your arm down and hear a blade. Fire a finger gun and hear the shot. Wave and hear the crowd.

The sound effects you used to make with your mouth now play from your Apple Watch.

On your own, or with your kids. For cosplay, a party trick, or practice swings.

■ Three samples, ready to try

A finger gun (Sample Gun), a downswing (Sample Samurai), a wave (Sample Star). Three motions and three sounds are there from the start.

■ Register your own motion

1. Record it on the Apple Watch Press New and repeat the motion you want it to learn 10 times.

2. Name it on the iPhone The recording appears at the top of the home screen. Give it a name and pick a sound.

3. Swing the Apple Watch Just move your arm. It detects the motion it learned and plays the matching sound.

■ It gets better the more you use it

It will not be perfect at first. You fix a wrong detection on the spot.

• It should have fired but did not -> Learn, to make it detect that move
• It fired when it should not have -> Ignore, to stop it detecting that

Even without pressing anything, it learns what should fire and what should not.

Every correction moves it closer to the way you actually move.

■ Several motions can be detected at once

Every motion in a group is detected at the same time. Keep one set for a hero and another for boxing, and switch between them from the Apple Watch.

■ Detection runs on the Apple Watch alone (the iPhone is for the details)

Detection and the simple settings are done entirely on the Apple Watch. Adding motions and sounds, and renaming them, is done on the iPhone.

■ Nothing leaves your devices

There is no network access. Your recordings and your history never leave your devices, and no account is needed.

■ What you can do for free

• Use the three bundled motions and sounds as they are
• Teach it one motion of your own (re-record over it as often as you like)
• Make one group of your own
• Every feature for tuning detection (Learn, Ignore, judge time and more)

■ What the purchase adds

• Teach it as many motions as you like
• Make as many groups as you like
• Turn your own audio files into sounds

One-time purchase. Not a subscription.