[maffydub]

Congratulations to the Estimote guys! I've borrowed one of these to test out their signal strength/consistency.

(At a recent AngelHack, I built an indoor-positioning system based on triangulation of signal strength. I tested with a StickNFind BLE device and a couple of homemade BLE(-ish) devices based on nRF24L01 RF modules. I'm hoping the signal strength from the Estimote is going to be more consistent than these.)

[andrewtbham]

I got some estimotes and my experience is that the signal strength doesn't change consistently based on the distance. I was planning to do a program using trilateration... but I don't think it would work.

[maffydub]

My experience was that the RSSI does change reasonably consistently, but that there's quite a lot of noise (so you need to smooth it appropriately). I also get the impression that it's affected by orientation of the phone relative to the beacon, and also by anything blocking line-of-sight (including humans). Mounting the beacons high up could reduce the effect of this last point.

[tlack]

Let me know how accurate you can get your system. I was planning something similar but with the broad ranges offered by BluetoothLE/iBeacon I didn't expect to get much accuracy out of the system.

[boobear19]

I too have been working on triangulation - any code you can share?

[maffydub]

The code I have is at https://github.com/matt-williams/blook8r.

My trilateration code isn't great - I tried doing it properly and couldn't get it working in the 24 hours of the hackathon. Positioning along a 1D line using signal strength from two beacons was much simpler and I implemented this and then bodged in a third beacon using some averaging.