PiRacer CPP

The goal of this project is to implement PiRacer-py project in cpp so that no python is needed to develop PiRacer applications. Not every feature from the original project is implemented yet, but everything necessary for controlling the vehicle is there for you.

Install

Tested device:

• Raspberry Pi 4 Model B
• Waveshare PiRacer AI Kit

Tested distribution:

• Raspberry Pi OS "Bullseye" (64-Bit)

Install dependencies

sudo apt update
sudo apt install \
	pigpio \
	build-essentials \
	cmake

Enable I2C

Use raspi-config tool to enable I2C:

sudo raspi-config

• Interface Options > I2C > Enable

Afterwards, reboot:

sudo reboot

Examples

The following examples will show the basic functionality of PiRacer

forward_backward_left_right

Basic example code for testing steers and throttle

int main()
{
	...

	// Create PiRacer Instance
	PiRacer racer;

	// Forward
	racer.setThrottlePercent(0.2);
	sleep(2);

	// Backward
	racer.setThrottlePercent(-0.2);
	sleep(2);

	// Steering Left
	racer.setSteeringPercent(1.0);
	sleep(1);

	// Steering Right
	racer.setSteeringPercent(-1.0);
	sleep(1);
	
	...
}

gamepad_control

Read inputs from the gamepad and control the vehicle.

int main()
{
	// Create instances
	PiRacer racer;
	ShanWanGamepad gamepad;

	while (true)
	{
		// Read inputs from gamepad
		ShanWanGamepadInput input = gamepad.read_data();

		float steering = input.analog_stick_left.x;
		float throttle = input.analog_stick_right.y * 0.5; // limit throtle to 50%
		
		racer.setSteeringPercent(steering);
		racer.setThrottlePercent(throttle);
	}
}

Also it is possible to create gamepad instance with non-blocking mode like:

// set non-blocking flag to true
ShanWanGamepad gamepad("/dev/input/js0", true);

read_battery

Read battery status from the vehicle

int main()
{
	// Create PiRacer Instance
	PiRacer racer;

	float voltage = racer.getBatteryVoltage();
	float current = racer.getBatteryCurrent();
	float power = racer.getPowerConsumption();
	std::cout << "Battery "
			<< "Voltage: " << voltage
			<< ", Current: " << current
			<< ", Power: " << power
			<< std::endl;

	...
}

Building examples

Run follwing commands to build above examples:

mkdir build
cd build
cmake ..
make

pigpio library requires root permission to control gpio pins. So run example programs with sudo

sudo ./forward_backward_left_right

Keep in mind that to use gpio gpioInitialise() must be called in your program before using piracer instance. And when terminating the program, call gpioTerminate()

References

Raspberry Pi OS

pigpio

Waveshare PiRacer AI Kit

PiRacer-py

Adafruit_INA219

Adafruit_PCA9685