Tim Holum Tim Holum - 20 days ago 16
Linux Question

Bluetooth LE Signal Strength Linux

Hello is there any way to get the signal strength of near by bluetooth le devises in linux? Or any good libraries for nodejs, php or mono ( I do know some c++ or python but would prefer to say away from them ) if a tool does not exsist but would be fairly easy to write

Thank You

Answer

On Linux, the way to do this is with the hcitool command. However, you have to be connected to get the rssi of a device. If you want to achieve this from the command line, try:

#hcitool rssi AA:BB:CC:DD:EE:FF

If you want to see the actual C code to achieve this, take a look at the bluez tools/hcitool.c file, under the cmd_rssi function.

static void cmd_rssi(int dev_id, int argc, char **argv)
{
    ...
}

For Bluetooth Low Energy, I only know one way to do this, and that is using the #btmon command. Run btmon in the background then scan for Bluetooth Low Energy devices:

#./btmon &
# hcitool lescan

The results displayed on the monitor should be similar to this:

> HCI Event: LE Meta Event (0x3e) plen 12                                                                                  
      LE Advertising Report (0x02)
        Num reports: 1
        Event type: Scan response - SCAN_RSP (0x04)
        Address type: Public (0x00)
        Address: AA:BB:CC:DD:EE:FF (<Vendor Name>)
        Data length: 0
        ***RSSI: -34 dBm (0xde)***
AA:BB:CC:DD:EE:FF <Device Name>

Note that when using btmon you do not have to connect to get the rssi of a BLE device.

I hope this helps.

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