Python script to output bluetooth LE MAC addresses and current RSSI (signal strength)

btle-scan.py

import sys
import os
import struct
from ctypes import (CDLL, get_errno)
from ctypes.util import find_library
from socket import (
    socket,
    AF_BLUETOOTH,
    SOCK_RAW,
    BTPROTO_HCI,
    SOL_HCI,
    HCI_FILTER,
)

btlib = find_library("bluetooth")
bluez = CDLL(btlib, use_errno=True)

dev_id = bluez.hci_get_route(None)

sock = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI)
sock.bind((dev_id,))

err = bluez.hci_le_set_scan_parameters(sock.fileno(), 0, 0x10, 0x10, 0, 0, 1000);
if err < 0:
    raise Exception("Set scan parameters failed")
    # occurs when scanning is still enabled from previous call

# allows LE advertising events
hci_filter = struct.pack(
    "<IQH",
    0x00000010,
    0x4000000000000000,
    0
)
sock.setsockopt(SOL_HCI, HCI_FILTER, hci_filter)

err = bluez.hci_le_set_scan_enable(
    sock.fileno(),
    1,  # 1 - turn on;  0 - turn off
    0, # 0-filtering disabled, 1-filter out duplicates
    1000  # timeout
)

while True:
    data = sock.recv(1024)
    # print bluetooth address from LE Advert. packet
    addr = ':'.join("{0:02x}".format(ord(x)) for x in data[12:6:-1])
    rssi = (ord(data[-1]))
    print addr,rssi

Hi Mike,

First of all thanks for the code. I was wondering if you could possible explain the RSSI readings to me. What are the readings given in, db? If so why are they all positive and increase in value as the BLE beacon moves closer to the receiver. How I understand it is the closer that the value is to 0 the stronger the signal. My goal is to obtain an estimate as to how far the beacon is from the receiver. Any help would be greatly appreciated.

Regards
Eckaard

I have exactly the same question. I know this is quite old, but have someone figure it out by now ?
Thanks in advance