Week 8 – Unusual switch

Concept:

I designed a project inspired by one of my favorite arm exercises. The idea is to make the arm’s movement interact with light using an Arduino. I attached pieces of foil and wires on both sides of the arm at a specific distance. As the person bends their arm, the foil pieces move closer together. When the arm is fully bent, the foils touch and complete the circuit, causing both the yellow and blue LEDs to turn on. At the same time, the yellow LED starts blinking while the blue LED stays steadily lit. This setup transforms a simple arm exercise into an interactive experience. The lights provide visual feedback, it also makes the activity more engaging and helps represent effort and motion in a creative, easy-to-understand way.

Coding:

Arduino file on Github

int ledBlue = 8;      // Blue LED pin
int ledYellow = 4;    // Yellow LED pin
int foilSwitch = 2;   // Foil switch pin

void setup() {
  pinMode(ledBlue, OUTPUT);
  pinMode(ledYellow, OUTPUT);
  digitalWrite(foilSwitch, HIGH);
 
}

void loop() {
  int switchState = digitalRead(foilSwitch); // read foil switch

  if (switchState == LOW) {  // foils touching
    digitalWrite(ledBlue, HIGH);
    digitalWrite(ledYellow, HIGH);
    delay(500);                    // on for 500ms
    digitalWrite(ledYellow, LOW);
    delay(500);
    digitalWrite(ledBlue, LOW);
    digitalWrite(ledYellow, LOW);
  }
}

I defined three integers: ledBlue for the blue LED on pin 8, ledYellow for the yellow LED on pin 4, and foilSwitch for the foil sensor on pin 2. Then, in the setup part, I set the LEDs as outputs and used the internal pull-up resistor for the foil switch so it can detect when the foils touch each other. In the loop, I made the Arduino constantly read the state of the foil switch. When the foils touch, the circuit closes, and both LEDs turn on, the blue LED stays on, while the yellow LED blinks every half second. When the foils are not touching, both LEDs stay off.

Setup:

Photo SetupDemonstration Video

Reflection:

This project taught me how simple electronics can respond to physical movement and turn a regular arm exercise into an interactive activity. I learned how to use an Arduino to read input from a foil switch and control LEDs, as well as the difference between input and output pins and how HIGH and LOW signals work with a pull-up resistor. For future improvements, I could also try different colors or numbers of LEDs to show progress in a clearer way. Another improvement is to make the device more comfortable to wear on the arm, so it can be used easily during exercises. I could also practice adjusting the code to make the lights respond faster and more smoothly to the arm movement.