wiki:wireless/bluetooth/ledcandlegatt

Version 3 (modified by Ryan Erbstoesser, 10 months ago) (diff)

add pics for sniffing

Remotely Controlling LED Bluetooth Candle with the Gateworks GW16126 CATM1/BLE Mini-PCIe Adapter

Bluetooth Low Engery (BLE) is the latest communication standard in the Internet of Things (IoT) and M2M markets. Sensors that report small amounts of data periodically can last for several years using BLE. The Generic Attribute Profile (GATT) is one of the most common profiles used over BLE. Gateworks setup a LED candle that changes colors and brightness using BLE commands sent from a Gateworks SBC and GW16126 BLE radio. The GW16126 Mini-PCIe card features a u-blox NINA-B301 BLE module with custom Zephyr firmware to use HCI. It also has a u-blox SARA-R4 LTE Cat M-1 modem for pushing data up to the cloud. More can be read on the GW16126 wiki page

Hardware Requirements

  1. Gateworks SBC, preferably Ventana or Newport
  2. Gateworks GW16126 Mini-PCIe BLE & Modem Card
  3. LED Candle
  4. Android Smartphone
  5. Linux Host PC

Sniffing Bluetooth Packets

  1. Install Magic Hue app for the candle onto Android Phone
  2. Use Bluetooth settings on Android Phone to find and connect to the Magic Candle (LEDBlue-081051FE)

  1. Open Magic Hue and connect to Candle device and verify ability to change colors

  1. Connect Android phone to Linux computer (desktop or laptop)
  2. Allow USB Debugging on Android phone
  3. Under Developer Options in Settings on the phone, Enable Bluetooth HCI snoop log

  1. Go back to Magic Hue app and change the colors in a known sequence, such as Blue, Green, Red which will then be recorded in the log.

  1. On the Linux computer, use the following command to retrieve the Bluetooth Log immediately after changing the colors using the Android app:
    adb pull /sdcard/btsnoop_hci.log
    
  2. Open btsnoop_hci.log using WireShark? on the host PC
  3. Typically scroll to the bottom and find some events with protocol ATT.
    1. Note the Handle, value 0x002e
    2. Note the Value, 56:ff:00:00:00:f0:aa

Sending BLE Packets over GATT

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