Freenove 4WD Smart Car Kit for Raspberry Pi

A simple 4-wheeled robot built using the Freenove 4WD Smart Car Kit for Raspberry Pi. The wheels are mounted to a custom PCB that includes motor drivers and a few other circuits. Two servos control the "head" which contains a spot for an ultrasonic distance sensor (HC-SR04) and a Raspberry Pi camera. The Raspberry Pi connects to the circuit board with a custom jumper board. This kit requires a Raspberry Pi, and this repository uses a Raspberry Pi 4. You can purchase the robot (without the Raspberry Pi) at https://amzn.to/3KJOR2E.

Freenove is incredibly helpful, and I highly recommend this kit for learning purposes or as a proof of concept. The mechanical performance may not be as high quality as expected, but it is a great starting point. Freenove also provides a Github repository (https://github.com/Freenove/Freenove_4WD_Smart_Car_Kit_for_Raspberry_Pi) containing all instructions and the code needed to set up and run the robot.

Instead of using the official repository, this project was built (with the help of Chat-GPT) to use the Adafruit CircuitPython libraries on the Raspberry Pi. It does not use the IR sensors on the robot, which are a bit too low to the ground to work effectively in my house. It also does not use the camera.

This repository contains a CLI tool that allows the robot to be calibrated and wander around a house (albeit, ineffectively). The code is not super smart and is used to illustrate super simple behavior.

Setup

1. Follow the setup for CircuitPython first, as it installs some required site packages: https://learn.adafruit.com/circuitpython-on-raspberrypi-linux/installing-circuitpython-on-raspberry-pi

2. Set up a virtual environment and activate it:

python -m venv --system-site-packages .env
source .env/bin/activate

3. Install the required Python packages:

pip install -r requirements.txt

Code Structure

1. Robot class: The robot.py file contains the Robot class that represents the physical robot. This class includes methods to control the robot's motors, servos, and sensors.

2. Command Line Interface (CLI): The main.py file contains the RobotCLI class, a command-line interface for interacting with the robot. The CLI allows you to calibrate the robot, view its state, and control its movement.

3. Robot behavior: The main.py file also contains functions that define the robot's behavior, such as sweep_distances, get_furthest_distance, and rotate_to_target_distance. These functions are used by the CLI to enable the robot to wander around a house.

Usage

After setting up the environment, run the CLI tool with the following command:

python main.py

This will open the Robot CLI, where you can enter commands to control the robot, such as calibrating its servos or making it wander around.

Available CLI Commands

1. calibrate: Calibrate the robot's servos to ensure they are centered properly.
2. state: Display the current state of the robot, including motor speeds and servo positions.
3. wander: Make the robot wander around the house while avoiding obstacles.
4. exit: Exit the Robot CLI and stop the robot.

Example Usage

$ python main.py
Welcome to the Robot CLI!
> calibrate
Calibrating servos...
> state
Motor speeds: left=0, right=0 | Servo positions: left=90, right=90
> wander
The robot is now wandering around the house. Press Ctrl+C to stop.
> exit
Exiting the Robot CLI. Goodbye!

Contributing

Feel free to submit pull requests or open issues if you have any improvements, bug fixes, or suggestions. Your contributions are always welcome.

License

This project is licensed under the MIT License - see the LICENSE file for details.