Bluetooth Signal Strength in Android

Question

I wanted to get the RSSI value to measure how far a device is from a handset...the problem I am currently facing is whether the RSSI value keeps on changing even after the devices are paired and also if can the value be directly used as short?

Answer 1

The RSSI value will fluctuate significantly. It is proportional with distance, but it is affected by interference, and also by the 2 connected devices' power table (they might reduce their tx power if they are close).

That being said, RSSI will still appreciate with devices getting closer.

I preferred logging the RSSI data I receive on my other(embedded) device and sending it back to Android, showing it there. My embedded device has clear access to the Bluetooth stack, and so can get more accurate and more intense readings of the RSSI.

Ofc, getting the RSSI of the other device from Android should also work, but probably not so good (you have too many layers on top of the actual Bluetooth stack - linux bluez, then Android...).

I have my own graphing application for Bluetooth RSSI monitoring in Android, here are 2 printscreens from my app:

You can also look at Link Quality...this is another useful parameter(it it susceptible to duplications of the signal).

Here is a scientific paper on the subject.