Bluetooth Telemetry radio

` A Bluetooth Data Link , such as an HC-06 module can be used to connect your Pixhawk (or other controller) to your Bluetooth enabled PC or Android Ground station at distances up to 50m.

Note

this module’s baud rate usually must be changed from its default of 9600 to 57600 for use with ArduPilot. This is usually accomplished connecting it to a FTDI USB-serial adapter and using AT commands in a terminal program like Putty. See the last section of this page for more information on setting up the HC-06.

Connecting to the Autopilot

The Bluetooth data link often comes with both a DF13 6 pin and 6-to-5 pin connector which make it easy to connect to the autopilot’s serial ports. Note that any unused serial port on the autopilot can be used.

Once you have connected the Bluetooth data link you can power up the autopilot. It is OK to use USB connected power while using the Bluetooth module connected to the autopilot as long the the total power of ALL autopilot connected peripherals do not exceed the computer’s capability (usually 1A)

Bluetooth data link’s LEDs:

• Red LED blinks at 1hz : device is working, not connected

• Red LED blinks at 0.5z : pairing

• Red LED solid : connected

AutoPilot Setup

On the autopilot SERIAL port that the module is attached (we will use SERIAL2, sometimes labeled TELEM2, for the following), make sure it’s parameters are set as:

• SERIAL2_BAUD = 57 (57600)

• SERIAL2_PROTOCOL = 2 (MAVLink2)

Connecting with Mission Planner

Many PCs and Laptops have bluetooth adapters built in but if not then you can use a generic USB Bluetooth dongle (pic above) or use an additional Bluetooth data link connected via an FTDI Cable.

After first making sure your autopilot is powered on, and your PC’s bluetooth dongle is plugged in and installed, click on the Windows task bar’s little up triangle (aka “show hidden icons”) which should be on the bottom right of the screen.

The “hidden icons box” should appear. Right-mouse-button-click on the BlueTooth icon and select “show Bluetooth devices”

Windows should bring up the devices box. Any devices you may already have connected by Bluetooth will be in this box. If you have not connected any BT devices before this box will be empty. Select “Add a device”.

Windows will search for BT devices for you. If you have any BT devices turned on they will show up here (like perhaps your cell phone) ignore any other devices and select the HC-05 or HC-06 (or Linvor) .

Select Paring using device code.

Enter the device code (1234 or 0000) this is the default code.

Once paired right click the device and select “properties” The check box for Comm Port SPP should be checked (also note the com port number).

In device manager select Com Ports

Choose the comm port you noted in the above step.

Right click and select “properties”

Change baud rate to 57600

Your Bluetooth device should now be ready and you can connect to the port presented by the BT adapter in Mission Planner at the baud rate of 57600 (red LED steady on and not flashing)

Connecting From your Android ground station

These instructions will show you how to connect to your vehicle from Android device with a GCS app (like QGC, etc.) using the Bluetooth module.

Open the Android device’s settings panel and turn Bluetooth connectivity ON (usually by sliding a slider to the right). In the same settings screen click on “Bluetooth” which should cause a list of AVAILABLE DEVICES to appear

Power the vehicle and the “HC-06” (or whatever name you have changed it to below) device should appear. Click on it and enter “1234” or “0000” as the PIN to pair with the device, then select OK.

The device will appear under “PAIRED DEVICES”

Then start you Android based ground control station and connect the Bluetooth data stream. Some systems will automatically ask you select the GCS application to use the BT connection. Sometimes you will have to explicitly setup the BT connection within the GCS application.

How to Change Baud Rate, Device Name and Device PIN

You will need a FTDI to USB cable to change any of the configurations of the device (not supplied). Often the baud rate must be changed from 9600 to 57600.

To change the above you need a “Terminal” emulator program. You can not use “Putty” (a popular serial port tool) because it will not accept “line” commands. The Bluetooth Modules read the input at a rate of once per second therefore you must use an emulator that will allow you to input an entire line before hitting “send”. You can use the Arduino IDE to send commands to the com port if you are familiar with that. I use “Advanced Serial Port Terminal” but any terminal emulator that allows you to type in a line of text before hitting send will work just a good.

See this video for an example.

Change the baud rate

The index after the command AT+BAUD corresponds to the following baud rate:

1—-1200bps

2—-2400bps

3—-4800bps

4—-9600bps (usually the default)

5—-19200bps

6—-38400bps

7—-57600bps (how we setup the autopilot to communicate)

8—-115200bps

There are additional baud rates. Warning! do not set these baud rates unless you have a special fast UART chip. If you don’t know do not use these rates they are beyond the standard PC UART speed and once set you will loose communication with the device and the only way to contact the device after that will be with a high speed UART. (these are for reference only)

9—-230400bps

A—-460800bps

B—-921600bps

C—-1382400bps

The change of Baud rate takes effect immediately after the command is sent. So if you want to keep configuring the Bluetooth module, you need to set the Baud rate of your terminal program to the new Baud rate the Bluetooth is using. To test it, send AT again, you should receive ‘OK’

Change the Device Name

This example show you how to change the name of the Bluetooth module to ArduPilot: In the terminal program, send the command (case sensitive):

AT+NAMEArduPilot

The Bluetooth should reply:

OKsetname

Change the Device PIN

The following example shows how to change the pairing code to 5566 In the terminal program, send the command (case sensitive):

AT+PIN5566

The Bluetooth should reply:

OKsetPIN

Troubleshooting

You can test the device by making a loopback from TX to RX.

Open your terminal program select the correct comm port and in terminal type anything you like. If you see the test displayed then your device is working properly. If you do not see the text you typed and you have selected the correct comm port and your device is paired and connected (red LED solid on not flashing) then you may have a problem with your device.

Specs

Dimensions : 1.4” x 0.6” x 0.17”

Weight 9.6 g (0.3 oz)

Operation voltage: 3.6 to 6 V

I/O level: 3.3 V

Typical -80dBm sensitivity

Up to +4dBm RF transmit power

UART interface with programmable baud rate

Default baud rate: 57600

Supported baud rates: 1200, 2400, 4800, 9600, 19200,38400, 57600, 115200, 230400, 460800

Pairing code: 1234 or 0000

Auto-connect to the last device on power as default

Permit pairing device to connect as default

Integrated antenna

Range: 50 m