freenove-car-connection-v2

An environment to control and manage a Freenove_4WD_Smart_Car_Kit_for_Raspberry_Pi.

Structure

The server is the car and a client is a remote host.

Folder 'Code'

File client.py handles all TCP connections with the car. (used by Flask server) Three sockets can be opened :

• one for sending commands to the car (e.g. rotate servos, light up LEDs...)
• one for the camera stream
• one for retrieving car information (e.g. CPU usage, battery percentage...)

Folder 'car_utilities' contains low-level code to interact with the car Raspberry Pi. (from original repo)

Flask application

The file app.py is the Flask application entry point. A Flask server used to control the car via HTTP. The Flask application handles the client side by creating sockets. Endpoints are used to control and manage the car. Multiple clients are allowed.

Server

The file server.py is the server to be launched on the car. Handles incoming client connections and requests.

Usage

Server

Launch sudo python3 server.py on the car

Client

Run ./venv/bin/flask --app app run to start the Flask app.

Flask endpoints

First, initialize the connection by sending a GET request to /connect/{car_pi}.
⚠️ Every endpoint must have the ci= (client index) argument which indicates to which car to send the commands.

Name	Required	Type	Description
ci	required	integer	The car index

GET /connect/{car_pi}

set up the connection between the client and a car

GET /setLED

Lights an LED according to a given color.

Parameters

Name	Required	Type	Description
value	required	string	The LED index follow by three integers for RGB color. LEDINDEX_REDVALUE_GREENVALUE_BLUEVALUE e.g. value=0x01_255_255_255 will turn the LED 1 white

GET /setMotors

Change the speed of the wheels.

Parameters

Name	Required	Type	Description
value	required	string	The speed for the four wheels. LEFTUPPERWHEEL_LEFTLOWERWHEEL_RIGHUPPERWHEEL_RIGHTLOWERWHEEL e.g. value=2000_2000_2000_2000 will make the car go forward

GET /setServo

Change the orientation of the servos.

Parameters

Name	Required	Type	Description
value	required	string	The servo ID followed by the degree of the angle. SERVOID_DEGREES e.g. value=0_90 will turn the servo 0 to 90 degrees

GET /toggleBuzzer

Activate or deactivate the buzzer.

Parameters

Name	Required	Type	Description
value	required	integer	The activation value . ACTIVATIONVALUE e.g. value=0 will turn on the buzzer

GET /start_recording

Start a video recording.

Parameters

Name	Required	Type	Description
framerate	required	integer	The number of frames per second captured.
height	required	integer	The height in pixels of the video.
width	required	integer	The width in pixels of the video.

GET /stop_recording

Stop the current video recording.

GET /data_collection_on

Activate the data collection.

GET /data_collection_off

Deactivate the data collection.