The rattling you hear is the vibration motor. Put your phone on silent, get a phone call, and your phone vibrates when it rings. The phone doesn't just randomly shake, it has a small motor inside that turns quickly, which holds a small but offset weight (usually a half-circle), causing a slight vibration.
The accelerometer is a piece of silicon so it is not the rattling noise. Mine has the rattle and I know several people with 3G iPhones that don't so I assume it is just one of the aerials loose and flapping around. If that is the case the it is nothing to be concerned about.
However, if you feel a large object is moving around inside like the battery then I'd suggest taking it to your local Apple store before it breaks something.
Think you've misunderstood this thread.
No, I don't believe I have.
The OP stated "just as the title reads if i shake my iphone i hear a rattling sound my iphone runs fine and as far as i can tell the accelerometer works too. but this mysterious ratlling sound exists ".
If you take an iPhone, and shake it, it will rattle. This rattle noise is the vibration motor. (which should be off unless the phone is ringing)
This motor has a small crankshaft that has a weight on the end of it, as pictured in my previous post. When powered, this offset weight spins, causing a vibration. Although when not powered, the crankshaft is not locked into place, therefore shaking the phone will produce a rattle.
This motor has a small crankshaft that has a weight on the end of it, as pictured in my previous post. When powered, this offset weight spins, causing a vibration. Although when not powered, the crankshaft is not locked into place, therefore shaking the phone will produce a rattle.
Please explain why mine doesn't rattle.
In which direction are you shaking it?
Try holding the phone so it stands upright, and then shake it side to side. (screen facing towards you) You should hear a feint sound. In my opinion, it sounds like more of a clicking noise than a rattle, but it can be described as both.