使用btmon监测

在一个终端中

sudo btmon | grep RSSI

在另一个终端里面

sudo hcitool scan

结果如下
sudo hcitool scan 终端中

pi@raspberrypi:~ $ sudo hcitool scan
Scanning ...
    12:34:56:78:90:10   NAME1
    11:22:33:44:55:66   NAME2

sudo btmon | grep RSSI 终端中

pi@raspberrypi:~ $ sudo btmon | grep RSSI
> HCI Event: Inquiry Result with RSSI (0x22) plen 15           [hci0] 22.072105
        RSSI: -61 dBm (0xc3)
> HCI Event: Inquiry Result with RSSI (0x22) plen 15           [hci0] 25.049621
        RSSI: -35 dBm (0xdd)

Screenshot at 2017-04-25 21:41:56.png

也可以在一个终端中

sudo btmon | grep RSSI &
sudo hcitool scan

使用watch命令持续监测RSSI波动

sudo btmon | grep RSSI &
watch sudo hcitool scan

结果如下

 HCI Event: Inquiry Result with RSSI (0x22) plen 15          [hci0] 657.483695
                              RSSI: -40 dBm (0xd8)
                                                       > HCI Event: Inquiry Result with RSSI (0x22) plen 15          [hci0] 689.840062
                              RSSI: -39 dBm (0xd9)
                                                       > HCI Event: Inquiry Result with RSSI (0x22) plen 15          [hci0] 724.036462
                              RSSI: -56 dBm (0xc8)

watch命令默认两秒监测一次，实际上由于监测本身需要时间，间隔会超过两秒。 使用参数可以更改watch监测频率

watch -d - n 1 sudo hcitool scan
-n后面跟1 表示每1秒监测一次，当然0.1也是可以的，不过监测的频率貌似并不取决于watch，而是btmon;-d高亮显示 每次监测的不同。

 HCI Event: Inquiry Result with RSSI (0x22) plen 15         [hci0] 1024.834480
                              RSSI: -49 dBm (0xcf)
                                                       > HCI Event: Inquiry Result with RSSI (0x22) plen 15         [hci0] 1055.730270
                                                               RSSI: -51 dBm (0xcd)
                                                       > HCI Event: Inquiry Result with RSSI (0x22) plen 15         [hci0] 1088.836020
                              RSSI: -73 dBm (0xb7)