itp blog

Pcomp wk 2

2 min read

Lab: Digital Input and Output with an Arduino

1.

Button Not Pressed (open switch)
  • The switch does not connect to +3.3 V.
  • The shared row (the “node” with D2 + resistor) is only tied to ground through the 10 kΩ resistor.
  • Voltage at D2 = 0 V (LOW).
Button Pressed (closed switch)
  • The switch connects +3.3 V directly to the shared row (node).
  • The node rises to +3.3 V, so D2 = HIGH.
  • A small current (~0.33 mA) flows from +3.3 V → node → resistor → ground.

When the button is pressed

  • Pin 2 goes HIGH (reads 3.3V).
  • Arduino turns Red LED (D3) ON.
  • Arduino turns Yellow LED (D4) OFF.

When the button is released

  • Pin 2 goes LOW (0V).
  • Arduino turns Red LED (D3) OFF.
  • Arduino turns Yellow LED (D4) ON.

The button is acting as a digital switch.

The Arduino is reading that switch (HIGH/LOW).

Depending on the input, it chooses which LED to light.

At any moment, only one LED is ON (they alternate). 3.

I understood the hardware part of it but not so much of the code.

I really wanted to understand it though…

Below is what my GPT teacher taught me. I think I kind of get what it means.

What I can take out of this :

analogValue will take the potentiometer value information. that will range 0 – 1023.

brightness will hold the scaled version of analogValue by dividing the analogValue by 4, it will range 0 – 255.

Serial.begin(9600); – Starts the serial connection so the Arduino can send data to your computer at 9600 bits per second.

pinMode(ledPin, OUTPUT); – Without this, Arduino wouldn’t know whether to drive the pin or just read it.

analogWrite(ledPin, brightness); – Sends a PWM signal to pin 9 with duty cycle based on brightness.

  1. using FSR : didnt not work as it supposed to .

void loop() {
 
  rightSensorValue = analogRead(A0); // read the pot value
 
  // map the sensor value from the input range (400 – 900, for example)
 
  // to the output range (0-255). Change the values 400 and 900 below
 
  // to match the range your analog input gives:
 
  int brightness = map(rightSensorValue, 10, 900, 0, 255);
 
  brightness = constrain(brightness, 0, 255);
 
  analogWrite(whiteLED, brightness);  // set the LED brightness with the result
 
  serial.print(“sensor: “);
 
  Serial.println(rightSensorValue);   // print the sensor value back to the serial monitor
 
  serial.print(”  brightness: “);
 
  Serial.printIn(brightness);
 
  delay(1);

Graph View