Obstacle Avoidance Car

This is a simple, yet easy and fun to make robotics project. it features an Arduino connected to 2 little n20 motors, (they only draw between 15 t0 20ma, so it is safe) an ultrasonic sensor (HC-SR04) housed in a 3d printed body (u can use anything it doesn't matter :) . It is powered by 2 1200mah cells and the motors are connected to n20 wheels. you can also put on a castor wheel, as in this case i used an n20 castor wheel. it doesn't require a motor driver which might be a big relief to you since every other obstacle avoidance car uses a motor driver and 80% percent of the people dont have that.

1. n20 castor wheel
2. ultrasonic sensor
3. structure for robot
4. 2x 3.7v li-ion cells (16046)
5. li-ion cell holder with barrel jack
6. Arduino uno
7. n20 wheel
8. n20 motor 6v 150 rpm (geared)

1. connect the the vcc of the ultrasonic sensor to the 5v of arduino
2. connect trig of the sensor to pin 2
3. connect echo of the sensor to pin 3
4. connect gnd of the sensor to gnd of the arduino

1. connect the positive terminal of the left motor to pin 12
2. connect the negative terminal of the left motor to pin 8
3. connect the positive terminal of the right motor to A1
4. connect the negative terminal of the right motor to A0

the code-

// C++ code

//

int distance = 0;

long readUltrasonicDistance(int triggerPin, int echoPin)

{

pinMode(triggerPin, OUTPUT); // Clear the trigger

digitalWrite(triggerPin, LOW);

delayMicroseconds(2);

// Sets the trigger pin to HIGH state for 10 microseconds

digitalWrite(triggerPin, HIGH);

delayMicroseconds(10);

digitalWrite(triggerPin, LOW);

pinMode(echoPin, INPUT);

// Reads the echo pin, and returns the sound wave travel time in microseconds

return pulseIn(echoPin, HIGH);

}

void setup()

{

pinMode(8, OUTPUT);

pinMode(12, OUTPUT);

pinMode(A0, OUTPUT);

pinMode(A1, OUTPUT);

}

void loop()

{

if (0.01723 * readUltrasonicDistance(2, 3) < 25) {

digitalWrite(8, LOW);

digitalWrite(12, LOW);

digitalWrite(A0, LOW);

digitalWrite(A1, LOW);

delay(1000); // Wait for 1000 millisecond(s)

digitalWrite(8, LOW);

digitalWrite(12, LOW);

digitalWrite(A0, LOW);

digitalWrite(A1, HIGH);

delay(2000); // Wait for 2000 millisecond(s)

} else {

digitalWrite(8, LOW);

digitalWrite(12, HIGH);

digitalWrite(A0, HIGH);

digitalWrite(A1, LOW);

delay(2000); // Wait for 2000 millisecond(s)

}

}

the file attachment is below:)