Leap Motion controller is futile gesture

I loved the idea of controlling a personal computer by waving my hands — until I tried it. After a few days with Leap Motion, a new device that turns gestures into digital commands, I came away with sore arms and a new respect for the computer mouse.

The Leap Motion gesture detection system is a sleek and sophisticated device. But it works with only a limited set of software, and even then, not very well. I’m sure it will get better as developers enhance the software, but so what? The very capable engineers at Leap Motion have created a solution to a problem that nobody’s got.

Nobody but Microsoft Corp., perhaps. The interface for the newish Windows 8 operating system lets users scroll through a menu of apps by stroking the screen. But most people don’t own touchscreen computers, and plummeting PC sales prove that few of us are buying new ones. But plug the $80 Leap Motion device into any late-model Windows or Apple Inc. Macintosh machine, and you’re supposed to get touchscreen-like performance, without leaving fingerprints.

Setting up Leap Motion is simple — indeed, too simple. Plug the device into a USB port of your Internet-connected computer, then place the Leap Motion sensor in front of the keyboard. Download the control software and that’s that. A well-designed visual tutorial shows you basic moves you can make.

But there’s no detailed user manual, either in the box or online. That’s fine for an iPhone; its functions are obvious. But you can’t just turn on Leap Motion and start waving. You must do it just right, and learning how is a constant nuisance.

Leap Motion tracks your movement with the same kind of infrared light emitted by your TV’s remote control. That means your fingers have to stay inside an invisible cone of light rising from the top of the device.

Since you can’t see the beam, it’s hard to know whether your hands are in the right place. Hold them too close to the computer screen, or too far away, and Leap Motion loses track of them. Since your hands touch nothing but air, there’s no tactile sensation to help you find the correct position. Instead you’re guided by on-screen cursors.

Just like using a mouse pointer, right? Not quite. Say you want to activate an on-screen button. With Leap, there’s no button to click. Instead, you just move your finger closer to the screen. How close? Figure it out yourself.

The cursor often flickered randomly about the screen, even when I held my hands steady. And it often didn’t line up with my finger; an irritating trait when trying to kill bad guys in an otherwise enjoyable Western shoot-out game. The same problem arose with every app, including Touchless, a program that let me scroll through Windows 8’s on-screen icon, but only if I held my hands just right. With the slightest deviation, it stopped working. As a touchscreen substitute, I found Touchless barely adequate.

Worst of all was using Leap Motion with Google Earth, a software simulation of the entire globe. I’d hoped to gently rotate the planet for a bit of sightseeing, but at the slightest twitch of a finger, it began spinning uncontrollably. It looked cool, but it made the program useless.

Leap Motion doesn’t work with most Windows or Mac software. Instead, you choose from about 75 software apps including games, music composition programs, and drawing apps. But using them is a challenge, because Leap Motion hasn’t created a standard “vocabulary” of hand gestures. It’s as if your mouse worked one way in Microsoft Word and another way in the Firefox Web browser. Even the size, shape, and color of the cursor changes from app to app.

This lack of fixed standards permits some clever innovations. For instance, The New York Times app lets you scroll through stories by twirling your finger in the air. But if the Globe brings out a Leap Motion app, I might have to learn a different gesture. It’s hardly worth it.

The success of Microsoft’s Kinect video game controller shows that motion tracking has its uses. But why pay $80 to wave at your computer like a tourist on a cruise ship, when your mouse will do the same things, and almost always better?