Week 9 – Sensors

Concept: 

When thinking about an idea for this project, I kept coming back to the lights in my room and how they always stayed the same, no matter what the light outside was like, they were either always to bright or too dim. That simple thought inspired me to create a system where they could adjust automatically, so if it’s bright during the day, the lights would stay dim or even stay off, but as the sun sets and it gets darker, they would gradually get brighter and adjust to the environment. 

Implementation/ Setup: 

To implement this, I used the LDR and a button. The button would serve as a simple on/off switch for the LEDs, which would allow me to activate or deactivate the system manually. Then, once the LEDs are turned on, the LDR would take over by detecting the light levels in the room. This means as it gets darker outside, the LDR would read lower light values, which causes the LEDs to become brighter. On the other hand, if it’s bright out, the LEDs automatically dim or even turn off, since additional lighting isn’t really needed. Below is the set up and demo: 

Code/Challenges: 

One of the initial challenges I faced was figuring out how to use both the button and the LDR together in a way that made sense. I wanted the button to first be used to switch the system on, and then only after that should the LDR take over and adjust the LED brightness based on the surrounding light levels. To solve this, I used a boolean variable ledOn, which was inititally set as false, that toggles the LED system on or off when the button is pressed . Once the system is turned on (ledOn true), the LDR starts reading the  light and adjusts the LED brightness accordingly, so darker surroundings make the LEDs brighter, and brighter conditions dim the LEDs. This setup ensured that the button controlled the system’s activation, while the LDR only adjusted the lighting when the system was switched on.

// Detect button press (transition from LOW to HIGH)
 if (buttonState == HIGH && lastButtonState == LOW) {
   delay(50);  // Debounce
   ledOn = !ledOn;  // flips value of ledOn, toggles between on/off
 }


 lastButtonState = buttonState;  // Save current state for next loop


 if (ledOn) {
   // Read light level and map it to brightness
   int lightLevel = analogRead(ldrPin);  // 0 (dark) to 1023 (bright)
   int brightness = map(lightLevel, 0, 1023, 255, 0);  // Invert to make LED brighter in dark


  
   analogWrite(ledPin1, brightness);
   analogWrite(ledPin2, brightness);
 } else {
   // Turn LEDs off
   digitalWrite(ledPin1, LOW);
   digitalWrite(ledPin2, LOW);
 }
}

Reflection/Improvements: 

Reflecting on this project, one key area for improvement would be expanding the functionality of the button to maybe control more features. So, currently, the button toggles the LED system on or off, but I think it could also be used to switch between different modes or lighting patterns for more dynamic control. For example, I could program the button to cycle through several lighting modes. The first press could turn the system on with brightness adjusted by the LDR as it currently works. A second press could set the LEDs to a fixed brightness level, independent of the light conditions outside, giving the user more control over the lighting. A third press could switch the LEDs to a blinking pattern.