This project is about a car that turns to the left depending on how much light the photo resistor receives. The more light the photo resistor gets, the more it will steer to the left. I made this project to see what other things I can do with Legos using outside components. I also figured I should see what more the world had to offer than strictly using Legos. As I entered uncharted territory, I did receive help along the way.
So now that I finally have my project done, let’s take a look at some of the features and improvements from the previous design.
This is the final version of my project.
This was the previous steering mechanism from the previous design.
This is the bottom of the steering mechanism. The red pieces were designed to hit themselves against the 2 x1 blue brick so the wheels do not turn too far.
Here is the modified steering mechanism. Well, only a small part of this mechanism was modified to make sure that the car would actually turn left.
Another important feature was finding a creative way to get the servo to move the wheels. I gad a special rod that I was able to connect to the shaft of the servo. I used more Lego pieces around the servo so it would not move around.
The 4 x 2 red brick was a very good piece to hold the adjacent pieces from snapping easily.
This is where the magic happens. I used an Arduino Uno to control what was on the pcb board. Using only a 5volt battery, I powered a DC motor, a servo, a photo resistor, and a 5mm LED.
I used a DC motor to move 3 gear wheels to make the car move around. I soon found a way to make the 8-teeth gear wheel fit snug with the DC motor.
This was an early schematic of the car:
This is the schematic for the newer model:
Here’s the video explaining the car:
And finally, my code for this project:
#include <Servo.h>
Servo myservo; // create servo object to control a servo
// a maximum of eight servo objects can be created
int pos = 0; // variable to store the servo position
int lightPin = 0; //the analog pin the photoresistor is
//connected to
//the photoresistor is not calibrated to any units so
//this is simply a raw sensor value (relative light)
//LED Pin
int ledPin = 11; //the pin the LED is connected to
//we are controlling brightness so
//we use one of the PWM (pulse width
// modulation pins)
int motorPin = 5; // define the pin the motor is connected to
// (if you use pin 9,10,11 or 3you can also control speed)
void setup()
{
myservo.attach(9); // attaches the servo on pin 9 to the servo object
pinMode(ledPin, OUTPUT); //sets the led pin to output
pinMode(motorPin, OUTPUT);
}
void loop()
{
//myservo.write(0);
//delay(1000);
//myservo.write(180);
//delay(1000);
int lightLevel = analogRead(lightPin); //Read the
// lightlevel
lightLevel = map(lightLevel, 0, 900, 0, 180);
//adjust the value 0 to 900 to
//span 0 to 255
lightLevel = constrain(lightLevel, 0, 180);//make sure the
//value is between
//0 and 255
analogWrite(ledPin, lightLevel); //write the value
myservo.write(lightLevel);
delay(50);
digitalWrite(motorPin, HIGH);
}