Gesture Controlled Drone #2 : Preperation - Drone

24 May 2021

The DJI Tello is a small-sized drone that combines powerful technology from DJI and Intel into a very tiny package. It is a lightweight, fun, and easy-to-use drone that is the perfect tool for learning the ropes of drone piloting before investing in a more expensive option. Tello boasts a 14-core processor from Intel that includes an onboard Movidius Myriad 2 VPU (Video Processing Unit) for advanced imaging and vision processing. It is equipped with a high-quality image processor, for shooting photos and videos. The camera features 5MP (2592x1936) photos and HD720 videos. The drone has a maximum flight time of 13 minutes. This incredibly small drone fits in your palm and only weighs approximately 80g (propellers and battery included). You can control Tello directly via the Tello app or with a supported Bluetooth remote controller connected to the Tello app. The drone is programmable via Python, C++, Scratch, and DroneBlocks.

DJI Ryze Tello

Specs

Weight: Approximately 80 g (with propellers and battery)
Dimensions: 98mm*92.5mm*41mm
Propeller: 3 inch
Built-In Functions: Range Finder, Barometer, LED, Vision System, WIFI 802.11n 2.4G, 720P Live View
Port: Micro USB Charging Port
Max Flight Distance: 100m
Max Speed: 8m/s
Max Flight Time: 13min
Detachable Battery: 1.1Ah/3.8V
Photo: 5MP (2592×1936)
FOV: 82.6°
Video: HD720P30
Format: JPG(Photo); MP4(Video)
Electronic Image Stabilization: Yes

Preparing Tello Drone for the project

The Tello drone SDK provides ample information on how to program the drone to achieve the tasks via Tello commands, but are somewhat limited in the features. The Tello SDK connects to the aircraft through a Wi-Fi UDP port, allowing users to control the aircraft with text commands. We use Wi-Fi to establish a connection between the Tello and the M5Stack module. Once powered on Tello acts as Soft AP Wi-Fi (192.168.10.1) to accept commands via port 8889. The Tello SDK includes three basic command types.

Control Commands (xxx)

Returns “ok” if the command was successful.

Returns “error” or an informational result code if the command failed.

Set Command (xxx a) to set new sub-parameter values.

Returns “ok” if the command was successful.

Returns “error” or an informational result code if the command failed.

Read Commands (xxx?)

Returns the current value of the sub-parameters.

Even though Tello is pretty maneuverable, with a number of different axes on which we can control the drone, in this project, we will use the following commands.

takeoff : Auto takeoff.
land : Auto landing.
up x : Ascend to “x” cm.
down x : Descend to “x” cm.
left x : Fly left for “x” cm.
right x : Fly right for “x” cm.
forward x : Fly forward for “x” cm.
back x : Fly backward for “x” cm.

Please refer to the SDK for a full set of commands.

As a safety feature, if there is no command for 15 seconds, the Tello will land automatically.

Tello APIAs we are using Arduino as the platform, we need an API that can translate our commands to UDP packets to be sent using the Arduino program. TelloArduino is an Arduino library for controlling DJI Tello through ESP32 Module. This library controls the Tello by sending commands via UDP as mentioned in the SDK documentation.

To download, enter the following command in the terminal (Mac/Linux) or command prompt Windows) or click the "DOWNLOAD ZIP" button.

$ git clone https://github.com/akshayvernekar/telloArduino.git

Place the "tello" folder in your Arduino sketch folder/libraries/ folder. Now Restart the IDE.
In your Arduino IDE, go to Sketch > Include Library > choose "tello" to include this library in your sketch.

References:

https://dl-cdn.ryzerobotics.com/downloads/Tello/Tello%20SDK%202.0%20User%20Guide.pdf

https://store.dji.com/product/tello

https://github.com/akshayvernekar/telloArduino