use phone headphone jack to make quiet vibration

In my work we cannot use vibration alerts on our phones as they are too loud. Got to thinking about how to make some sort of alert device that is quiet

(deleted)

Seems like we could read the audio as data and drive our own quiter vibrator. Or possibly some sort of bluetooth device like the watches we are starting to see in the market

(deleted)

Smarty pants. Looking for feedback on what might be a good approach. I'm at work not at my bench so just tossing ideas.

My first question I suppose is what would it take to "read" an audio alert via the headphone

You might look into the USM motors that camera makers use for autofocus. They are very quiet.

(deleted)

I linked to it once, but this might be a quiet way to alert a person: https://www.sparkfun.com/news/1385

But it should be easy for an arduino to detect a signal from a headphone jack.

Bret: In my work we cannot use vibration alerts on our phones as they are too loud.

How about putting the phone in your pocket? In a drawer? In a box inside a drawer? You get the idea. Surely making an existing phone a bit quieter is going to be far easier than making your own haptic alerter.

Peter the point being, I want to know when text is incoming, and vibration is too loud in my work environment.