Shivani Kannan - Working with Inputs and Sensors | Project

Intention

Integrate sensing into the circuits and read information from the environment around. When the switch is turned on, the LED output changes based on the input.

Process

Components: Breadboard, Light Sensor, Switch, LED, Jumper Wires, 2 Resistors

1. Building a circuit with 1 input and 1 output: light sensor and LED

2. Writing code for the LED brightness to change based on the lighting

3. Debugging: the light in the surroundings was too bright, so I had to modify the code adjusting the conversion scale based on the brightness.

4. Modifying circuit to include a second input: switch

5. Modifying code so the computer first checks if the switch is on and then gets data from the light sensor to modify the light brightness on the LED.

#include "Particle.h"

int photoPin = A0;
int photoReading = 0;
int ledPin = D1;
int ledBrightness = 0;
int switchPin = D2;


void setup() {
    pinMode(ledPin, OUTPUT);
    pinMode( switchPin , INPUT_PULLUP);
    
    Particle.variable("light", &photoReading, INT);
    

}

void loop() {
    
    int buttonState = digitalRead( switchPin );
    
      // Using a pulldown resistor we get a LOW
  // Signal when its on
  
  if( buttonState == LOW )
  {

      // Use analogRead to read the photo cell reading
  // This gives us a value from 0 to 4095
        photoReading = analogRead(photoPin);

  // Map this value into the PWM range (0-255)
  // and store as the led brightness
        ledBrightness = map(photoReading, 3000, 4095, 0, 255);

  // fade the LED to the desired brightness
        analogWrite(ledPin, ledBrightness);

  // wait 1/10th of a second and then loop
  }else{
    // otherwise
    // turn the LED Off
    digitalWrite( ledPin, LOW);
    
  }

}

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Product

An LED whose brightness changes based on the light it senses in the environment when it is turned on.

IoT - Simple Internet Appliance

Shivani Kannan - https://youtu.be/hdkb3GTVMQM

Reflection

Initially, I chose to work with a knock sensor. The sensor needed a different code; being unfamiliar with coding & circuits, I decided to start with the light sensor and experiment with the knock sensor. I also realized that clearly writing down what I wanted the code to do before coding makes things easier.

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Found In

DIoT 2024 Skills Dev II: Working with Inputs and Sensors

About

Integrate sensing into the circuits, read information from the environment around, and translate that into an LED output.

Shivani Kannan - Working with Inputs and Sensors