PART5.md

Receive telemetry data from the drone

In Part 4 you constructed a Node-RED Dashboard flow to send commands to the drone. In this Part 5 exercise, we will create a Node-RED Dashboard with gauges and charts to display telemetry data from the drone.

Receiving Tello Telemetry Data

Open port 8890/udp in your laptop firewall to receive Tello telemetry data. If you want to turn on the video stream, you will need to open port 11111/udp. Send commands and receive responses from the drone on port 8889/udp.

Linux

$ sudo firewall-cmd --permanent --add-port=8890/udp
$ sudo firewall-cmd --permanent --add-port=8889/udp
$ sudo firewall-cmd --permanent --add-port=11111/udp

Then reload the firewall to effect the changes:

$ sudo firewall-cmd --reload

If you want to list open ports, run this command:

$ sudo firewall-cmd --permanent --list-ports

Mac OSX

On Mac, use System Preferences to open the ports.

• Open System Preferences > Security & Privacy > Firewall > Firewall Options
• Click the + / Add button
• Choose 'node' application from the Applications folder and click Add.
• Ensure that the option next to the application is set to Allow incoming connections.
• Click OK.

Telemetry Data

The drone will send telemetry data to port 8890. The Parse Status into an object change node uses a JSONata expression to parse the telemetry data into an JSON Object.

• pitch : the degree of the attitude pitch.
• roll : the degree of the attitude roll.
• yaw : the degree of the attitude yaw.
• vgx : the speed of the “x” axis.
• vgy : the speed of the “y” axis.
• vgz : the speed of the “z” axis.
• templ : the lowest temperature in degree Celsius.
• temph : the highest temperature in degree Celsius
• tof : the time of flight distance in cm.
• h : the height in cm.
• bat : the percentage of the current battery level.
• baro : the barometer measurement in cm.
• time : the amount of time the motor has been used.
• agx : the acceleration of the “x” axis.
• agy : the acceleration of the “y” axis.
• agz : the acceleration of the “z” axis.

JSON Object example output:

{"pitch":7,"roll":33,"yaw":-29,"vgx":0,"vgy":0,"vgz":0,"templ":61,"temph":62,"tof":10,"h":0,"bat":43,"baro":39.96,"time":22,"agx":307,"agy":-324,"agz":-930}

Task

Begin with the Part5 starter flow and add gauge nodes to display telemetry:

• Temp
• Barometer
• Accel X
• Accel Y
• Accel Z
• Speed X
• Speed Y
• Speed Z

Add a Chart node to display

• Drone Height

Add a Text node to display

• Flight Time

Solution

There is a solution flow available if you need help or want to check your solution.

Launch the Node-RED Dashboard by turning to the Dashboard tab in the right menu and then click on the launch button.

Home | Node-RED | Setup | Commands | Dashboard | Telemetry | Mission | Pictures | Visual Recognition | Custom Classifier

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