Scan for nearby Bluetooth LE peripherals using HM-11 and Arduino. This works on any ble device that advertises itself: beacons, trackers, wearables.

The code puts the HM-11 into master mode, and then scans every minute for nearby devices. Software returns device name and id.

Connect the HM-11 pins to a 3.3v Arduino, or to a regular 5v Arduino through a logic level shifter.

    _______
   |       |          HM-11  -->  Arduino
 1 :       : 16       9           3.3V
   :       :          12          GND
   :       :          4 (RX)      3 (TX)
 8 :_______: 9        2 (TX)      2 (RX)
     HM-11