Balloon Cart with Proportional Deceleration

Project showcase

Components and supplies

Arduino UNO

Ultrasonic Sensor - HC-SR04 (Generic)

Arduino MotorShield Rev3

DC motor (generic)

About this project

Project for my System Controls class at Cal Poly Pomona. The cart and balloon are pulled up the incline via a motor. The motor speed is controlled with pulse width modulation and decreases proportionally with its distance from the wall of nails through use of an ultrasonic sensor. Once the cart is within 2 centimeters of the spikes it reverses back down the ramp. The wall of nails is able to be manually moved anywhere along the Velcro rails without changing the system performance.

Code

Code to control motor shield proportionally with an ultrasonic range finder Arduino

Apologies for this code not being as simple consolidated as I could've made it but printing to the serial monitor helps with debugging the system when tuning.

#include <AFMotor.h>    //Adds Motor shield library

#define trigPin 7
#define echoPin 6  

float v;
int duration;
long distance;
long distance1;
long distance2;

AF_DCMotor motor(1);

void setup() {
  Serial.begin(9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  motor.setSpeed(200);
  motor.run(RELEASE);
}

void loop() {
  do{
  distance = (duration/2) /29.1; 
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(1000);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration/2) /29.1;
  Serial.print("distance ");
  Serial.print(distance);
  Serial.println("cm");
  }while(distance <= 4 || distance > 40);

 do{
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(1000);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance1 = (duration/2) /29.1;
  Serial.print("distance1 loop ");
  Serial.print(distance1);
  Serial.println("cm");
  delay(100);
  v = ((float)distance1/(distance+1))*255;
  Serial.print("speed ");
  Serial.println(v);
  motor.run(FORWARD); 
  motor.setSpeed(v);
  Serial.println("Forward");
 }while(distance1 > 5);

motor.run(RELEASE);
motor.setSpeed(0);
delay(3000);

do{
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(1000);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance2 = (duration/2) /29.1;
  Serial.print("distance2 loop 2 ");
  Serial.print(distance2);
  Serial.println("cm");
  Serial.println("Backward");
  motor.run(BACKWARD);
  motor.setSpeed(150);
}while(distance2 <= 19);
motor.run(RELEASE);
delay(3000);
}