Installation

ESP32 setup

In the Arduino IDE choose the ESP32 Dev Module board. Paste the carLibrary directory into your arduino library folder. Then install the following libraries and their dependencies via the library manager in the IDE.

• AsyncTCP

Lastly install the ESPAsyncWebServer library as a .ZIP file from github and include it in the IDE.

Zumo34U4 setup

Select Arduino Leonardo as the board and download the following library and its dependencies using the library manager.

• Zumo32U4

Features

Setup

The carLibrary exposes a class named Car. Its constructor accepts a network name and password.

Car car("networkName", "networkPassword");

In the program setup call the member function initCar.

void setup() {
   car.initCar();
}

Buttons and driving

The carLibrary exposes nine void functions named w, a, s, d. e, q, triangle, circle and square. These are called when the corresponding buttons on the control panel are pressed, and released. They all accept a parameter bool button indicating whether the button is pressed down or released. The defined helpers UP and DOWN can be used to check the button direction.

void w(bool button) {
   if (button == UP) {
      // button is released
   } else if (button == DOWN) {
      // button is pressed
   }
}

To drive the car use the member function drive. This takes two arguments representing the speed of the left and right belt. These arguments are integers ranging from -100 to 100.

// drive forward max speed
car.drive(100,100);

// stop car
car.drive(0,0);

// sharp turn left at half speed
car.drive(-50, 50);

Driving with low speeds can be harmful to the motors. A MOTOR_LOWER_LIMIT has therefor been placed at 30. Trying to drive with speeds under this limit will result in the car stopping.

Sensor data

Sensor data can be fetched through the data array on the Car class. Each data point contains a value and flag. All data values are integers and are updated roughly 20 times per second. Whenever a data value is updated the data flag is set to true.

// reading data continously
int proxData = car.data[PROXIMITY].value;

// read data when it is available
if (car.data[PROXIMITY].flag) {
   int proxData = car.data[PROXIMITY].value;
   car.data[PROXIMITY].flag = false;
}

The available data can be fetched using the defined helpers.

Data	Range	Details
PROXIMITY	0 → 12	The closer the object the higher the value.
LINE	-100 → 100	When the line is to the right of the car the number is positive.
ENCODERS	n/a	Encoder counts 12 times per motor rotation.
READ_TIME	n/a	Time corresponding to one encoder reading in ms.
GYRO	-180 → 180	Car angle along the z axis.

Motor rotations: Because of the 75:1 gear ratio in the motor every 75th motor rotation corresponds to one rotation of the wheel.

Calibrating

• To calibrate the gyroscope use the member function calibrateGyro. This accepts an unsigned integer indicating the precision of the calibration. This value may typically be in the range of 1024 to 4096, although a higher number leads to better precision. The car must be completely still when calibrating. The buzzer will sound when calibration is done.

// calibrate gyro with 2048 as precision
car.calibrateGyro(2048);

• To calibrate the line sensors use the member function calibrateLine. This accepts a helper BLACK or WHITE indicating whether the car should read a dark line on a light background or the opposite. The car must be placed on a line when calibrating. The buzzer will sound when calibration is done.

// follow dark line
car.calibrateLine(BLACK);

Graphing data

The control panel can graph three seperate data streams. The member function sendData accepts two arguments; an int specifying the graph and the data to send.

// send gyroscope data to graph 1
car.sendData(1, car.data[GYRO].value);

// send variable speed to graph 3
car.sendData(3, speed);

To send continous data call the function in the program loop. The function will update the graph data roughly 10 times per second.