[hmexx]

Still not sure why any of this would add cost. it all happens on the iphone which already has these sensors. If you can tell in which direction the iphone is moving thanks to gyro/magno/accelo AND you have a distance from BT device of reasonable resolution, you should be able to figure out the location of the device you are tracking with small movements of the iphone.

I'm not great at geometry but I figure it should be possible. Not sure about accuracy though.

[zizzer]

I was talking about adding the sensors to the bluetooth sticker device, that's why it'd add cost.

The sensors in your phone won't help to work out where the sticker is. The bluetooth receiver in it is built to detect signals from any direction, so even if you rotate your phone, that doesn't help to work out which direction the signals are arriving from.

[hmexx]

Don't think you are understanding what I am suggesting.

If you know the movement of the phone, you can determine which direction of movement causes the largest increase in signal strength change. So the app would be basically doing what you do to find something (let me move this way, oh I'm colder, I should go the other way) but at a higher spatial and temporal resolution.