Week 9 – Shadow and Light

Concept

For this project, I decided to make a small interactive game called “Light & Shadow”. The concept is simple but fun: the yellow LED changes brightness depending on how much light the photoresistor (LDR) senses, and the blue LED only lights up when it’s dark and the button is pressed, basically “catching the shadow.” I liked that idea because it combines analog and digital inputs in a way that feels like a mini game.

The Process

The production process was mostly about setting up the circuit on the breadboard and figuring out how to connect everything correctly. Choosing the right resistors was harder than I expected,  sometimes the LEDs didn’t light up properly, and I had to try a few combinations before it worked. I also spent a lot of time drawing the schematic to make sense of the connections. I must have redrawn it several times to make it at least slightly understandable. Even now, I’m not 100% sure my plan is perfect, but it works!

Figure: the process of sketching the plan

The Finalized Sketch

The coding part was fun because it was simple enough to understand but still taught me a lot. I read the analog value from the photoresistor and mapped it to the brightness of the red LED, then used a simple if-statement to check the button and darkness to control the green LED. Seeing the LEDs react in real time to light and button presses made all the work feel rewarding.

int lightSensor = A0;
int buttonPin = 2;
int redLED = 9;
int greenLED = 8;

void setup() {
  pinMode(buttonPin, INPUT);
  pinMode(greenLED, OUTPUT);
  pinMode(redLED, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  int lightValue = analogRead(lightSensor);    // 0–1023
  int brightness = map(lightValue, 0, 1023, 255, 0); // dark = bright
  analogWrite(redLED, brightness);

  int buttonState = digitalRead(buttonPin);

  if (buttonState == HIGH && lightValue < 400) {
    digitalWrite(greenLED, HIGH);
  } else {
    digitalWrite(greenLED, LOW);
  }

  delay(100);
}

Reflection

Overall, this project was a great learning experience. I got hands-on practice with analog and digital inputs, using resistors correctly, and writing basic Arduino code. I also learned patience, both in wiring and drawing schematics. Even though some parts were frustrating or confusing, it felt really satisfying to see the LEDs respond the way I wanted. Next time, I’d probably try adding a buzzer or even a little LCD display to make it even more interactive.

The video demonstration

IMG_8850