[hmexx]

Regarding: 1:25...

They should be able to use the gyro/accelerometer to give their radar 'direction' as well no? You would just need to move around slightly for it to combine the data with the BT signal distance.

Guess it depends on the BT distance resolution.

[frankus]

You could do this with multiple devices at known locations. E.g. if you always keep your (latest-generation) Mac mini in the office, and your MacBook Air in the kitchen, and have programmed them as such, they could communicate with the app and give you a rough location for any tag.

Which would actually be a pretty cool project for someone: create a system for triangulating the approximate location of stuff in your house with strategically-placed fixed Bluetooth LE devices ("stuff" in the degenerate case meaning powered-up BLE hardware like an iPhone, or with these sorts of tags, things like keys and pets). Sort of like this project but wit less of the "getting warmer…getting colder" hide-and-seek aspect.

[zizzer]

Unfortunately a gyro and accelerometer would only be able to provide the orientation of the device, not its location relative to the phone.

[hmexx]

Yeah, but the gyro/accelerometer could provide short movement measurements, no? IF you combine that with the distance measurement you get from the BT device, you should be able to figure out the direction to the BT device?

[zizzer]

For simple dead reckoning you'd need to add a magnetometer into the mix as well, otherwise there's no way to know which direction the sensors are facing relative to anything else.

This would at least give you a compass heading that you could use when integrating the accelerometer data to give some kind of course over time.

It'd be pretty unreliable though and add a lot of cost.

[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.

[krembo]

Since each sticker is a transmitter and a receiver, isn't it possible to mount 3 stickers with known places around your house like GPS sattelites, which will calculate the cat's sticker (for example) distance from each of them and tell the exact location?

[zizzer]

Getting an exact location would be very tricky as the received signal strength can be affected by so many things (Thick walls, reflections, interference...).

I'd imagine you could get a rough location, but you'd need to go through some kind of calibration process first that involved going into different rooms/zones and telling the software where you were.

You might need extra reference sensors too. Ones that are in known locations that the system can use to scale the signal strength readings. That might help to combat some of the issues I mentioned above.