Making an iPhone vibrate requires nothing more than a simple call to Audio Services. Deciding on when your application should buzz is a different matter. The code for producing that short buzz effect is this:

AudioServicesPlaySystemSound (kSystemSoundID_Vibrate);

For this to run, you must include the Audio Toolbox headers and compile your application with the AudioToolbox framework.

Although the underlying Core Telephony framework offers subtle control over vibration pattern, duration and intensity, the Audio Services API does not. It offers a single buzz for a set duration. Your entire tactile vocabulary, therefore, is limited to this one call.

With one item to call upon, numerous apps have used it as a kind of blunt hammer for feedback. If your piece moves out of bounds, buzz. If a fish comes over to say hello and nibble your finger, buzz. If you swing your light saber, buzz.

It wouldn't be quite so bad if all the buzzes didn't feel exactly the same, if there was some programmatic way to differentiate that kind of feedback but in the current SDK, one size has to fit all. Access to more discrete levels of vibration control are off limits for App Store items and experiments such as haptic feedback for the keyboard have had very little space to explore due to this.

What's more is that a lot of these games and utilities don't really need a tactile component at least in its current inflexible incarnation and, after a while, the vibration distracts from rather than adds to the experience. I'd love to see an option to disable the vibrate feature for many App Store offerings.

In the end, I'd prefer if vibration was available with a greater feature set but that it was applied to real world uses with a lighter touch. I trust the developer community would be able to handle a more complicated API system for vibrations, just as they've managed to work with the rather fussy Audio Queues. Vibrations, like sounds, like images, are a way that a platform can express itself to the user. The iPhone would benefit from presenting a more capable and rich interface.