h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

The joypad for my Playstation can vibrate. It does this by rapidly rotating an axle that passes through a small weight. Because the axle is off-centre, when the motor spins, the weight and the joypad wobble.

This is all perfectly understandable to me.

What I'm having difficulty with is believing that this same mechanism is responsible for the vibrate function of my mobile phone, a Motorola V3. The thing already seems unbelievably compact, there simply doesn't seem like there's room in there for a motor with an eccentric weight on it.

Does anyone know how it's done for certain?

SoRB

Are you strange people living in the bottom of my compost bin ?
It doesn't vibrate but moves, groans and smells awful. I thought it was rats but I will have to investigate further now. I do live in Cornwall so had considered pixies but I always thought they were invented by the Tourist Board.
I attend my compost bin at about 1630 hours every night so kindly make yourself known.
Regards Jim
Pasty Eater 1st Class

To the original poster: I don't know for certain, but I suspect that cell phones vibrate using some sort of very small magnet somehow suspended in a very small space, with a very small but precisely controlled current fluctuation around it. Some engineer I am. Electronic engineering was never my strong suit anyway.

To the other reply: Cornwall, eh? You don't say.

- JD

Some Googling got me an Elmo toy, which uses the same mechanism as cellphones, apparently: http://electronics.howstuffworks.com/question368.htm

"... attached to the gear, there is a small weight. This weight is about the size of a stack of 5 U.S. nickels, and it is mounted off-center on the gear. When the motor spins the gear/weight combination (at 100 to 150 RPM), the off-center mounting causes a strong vibration. Inside a cell phone or pager there is the same sort of mechanism in a much smaller version."

Sounds good to me

Ste

Generally all mobile phones vibrate using this method. Obviously the motor and spinning weight are smaller in these devices than in the games controllers.