Team LEDudes:

•

Robert Jenkins

Published November 24, 2017 © GPL3+

Light Up Your World

Dim the lights and get the party started with this Particle Photon project.

IntermediateFull instructions provided3 hours833

Things used in this project

Hardware components

Particle Photon

NeoPixel strip

Photo resistor

USB-A to Micro-USB Cable

Resistor 680 ohm

5 Volt 3 Amp DC Convertor

Jumper wires (generic)

Software apps and online services

IFTTT Maker service

Particle Build Web IDE

Particle Console

Story

Introduction:

As a college student, one ends up spending alot of time in their apartment. However, most college kids lack the interior decorating skills to create a fun, relaxing environment. More often than not, the room either goes undecorated or is randomly thrown together. Fortunately, there is a simple solution: LED light strips. They are extremely versatile, and can be used as either relaxing backlight for reading a book or flashing colors for a party with friends. However, why stop here? Our project, "Light Up Your World", allows for the LED light strip to be turned on and off using the two Particle Photons and the Internet of Things. By detecting the level of brightness in the room, the Photons can communicate to activate the LED strip without the user ever having to touch a button.

How It Works:

The first photon acts as a light sensor, measuring the analog signal across the A0 pin. A 680 ohm resistor and a photoresistsor are used together so that the the resistance varies depending on the amount of light that the photon is exposed to. In the code that is flashed to this photon, a threshold analog output of 40 was established as the distinguishing value between light and dark. Anytime that the room is light and the value is greater than 40, the photon publishes data to the cloud which says "broken". Anytime that the room is dark and the value is less than 40, the photon publishes data to the cloud which says "intact".

Photon 1: Reading the Brightness in the Room.

The second photon subscribes to the data that is published by the first photon. Whenver this photon reads "broken", it does nothing. However, whenever the photon reads "intact", it activates the WS2812B LED strip. It also activates the D7 on board LED, which acts as a trouble shoot to determine if the photons are communicating successfully.

When building this, use the female end of the WS2812B light string for your power and signal input. An external power supply is needed because the LEDs require a 5V input (the photon only provides 3.3V max) and a high current (60mA per light). For a string of 50 lights, that equates to 3A. Do not use the breadboard to connect the lights to the power supply because the breadboard may cause a significant power drop and cause a brown out. Another key is not to forget connecting the photon ground to the LED string ground.

Photon 2: Providing Signal to the WS2812B LED Light Strip

Using the individually addressable LEDs we were able to customize the lights in our apartment. We opted to light them up green for UNC Charlotte spirit, but any color can be used. The LEDs can also be customized into different patterns and animations. As you become more practiced with the NEOPIXEL library you can explore these options.

Video:

This is a short video which describes how the project works.

Graphs:

1 / 4 • Graph of Analog Voltage Response of A0 Pin to Varying Brightness

This first graph shows the analog output of the A0 pin as a function of brightness on the Particle Photon which uses the photoresistsor. To achieve this, the Particle Photon was taken into a completely dark room and the iPhone flashlight was shone onto the photoresistsor at different brightnesses. The second image shows the different levels of brightnesses that the iPhone can achieve. This graph was compared to the threshold value of 40 at which the Cloud message switches from "broken" to "intact" and the LED strip is activated.

The second graph was created using IFTTT. The third image shows the description of how the IFTTT program works. Whenever the analog output of the first particle photon is greater than the threshold value of 40, a new column is added to a Google Sheets spreadsheet with the value of the pin. Image four shows the second graph. The program was run over the course of several hours, but because the photon was in a consistently evenly lit room, the values remained constant over that span.

Code

// This #include statement was automatically added by the Particle IDE.
#include <neopixel.h>

int led = D7;


SYSTEM_MODE(AUTOMATIC);

// IMPORTANT: Set pixel COUNT, PIN and TYPE
#define PIXEL_PIN D2
#define PIXEL_COUNT 50
#define PIXEL_TYPE WS2812B

Adafruit_NeoPixel strip = Adafruit_NeoPixel(PIXEL_COUNT, PIXEL_PIN, PIXEL_TYPE);

int ledState = 0;



void stripSetPixelColor(unsigned char red, unsigned char green, unsigned char blue)
{
    uint16_t i;
    for (int i = 0 ; i < strip.numPixels() ; i += 1 )
    {
        strip.setPixelColor(i, strip.Color(red,green,blue));
    }
    strip.show();
}

void redStrip(uint8_t wait)
{
    stripSetPixelColor(255, 0, 0);
    delay(wait);
}

void orangeStrip(uint8_t wait)
{
    stripSetPixelColor(255,150,0);
    delay(wait);
}

void yellowStrip(uint8_t wait)
{
    stripSetPixelColor(255,255,0);
    delay(wait);
}

void greenStrip(uint8_t wait)
{
    stripSetPixelColor(0,255,0);
    delay(wait);
}

void cyanStrip(uint8_t wait)
{
    stripSetPixelColor(0,255,255);
    delay(wait);
}

void blueStrip(uint8_t wait)
{
    stripSetPixelColor(0,0,255);
    delay(wait);
}

void purpleStrip(uint8_t wait)
{
    stripSetPixelColor(255,0,255);
    delay(wait);
}

void magentaStrip(uint8_t wait)
{
    stripSetPixelColor(155,48,255);
    delay(wait);
}

void pinkStrip(uint8_t wait)
{
    stripSetPixelColor(255,0,150);
    delay(wait);
}

void whiteStrip(uint8_t wait)
{
    stripSetPixelColor(255,255,255);
    delay(wait);
}

void off(uint8_t wait)
{
    stripSetPixelColor(0,0,0);
    delay(wait);
}

int ledColor(String command)
{
    
    if(command == "White")
    {
        whiteStrip(20);
        return 1;
    }
    else if(command == "Pink")
    {
        pinkStrip(20);
        return 1;
    }
    else if(command == "Red")
    {
        redStrip(20);
        return 1;
    }
    else if(command == "Orange")
    {
        orangeStrip(20);
        return 1;
    }
    else if(command == "Yellow")
    {
        yellowStrip(20);
        return 1;
    }
    else if(command == "Green")
    {
        greenStrip(20);
        return 1;
    }
    else if(command == "Cyan")
    {
        cyanStrip(20);
        return 1;
    }
    else if(command == "Blue")
    {
        blueStrip(20);
        return 1;
    }
    else if(command == "Purple")
    {
        purpleStrip(20);
        return 1;
    }
    else if(command == "Magenta")
    {
        magentaStrip(20);
        return 1;
    }
    
    else if(command == "Off")
    {
        off(20);
        return 1;
    }
    
    else return -1; 
}

void setup() {
     pinMode(led, OUTPUT);
    digitalWrite(led, LOW);
strip.begin();
  strip.show(); // Initialize all pixels to 'off'
  /* Set up particle function to recieve code for  */
  Particle.function("ledcolor", ledColor);
  strip.setBrightness(100);
  Particle.subscribe("lights_off", myHandler);
}

void loop() {

}

void myHandler(const char *event, const char *data)
{
  
 
  if (strcmp(data,"intact")==0) {
    // if your buddy's beam is intact, then turn your board LED on
     digitalWrite(led, HIGH);
     off(50); 
     
     
  }
  else if (strcmp(data,"broken")==0) {
     digitalWrite(led, LOW);
    greenStrip(50);
    
  }
  
  
}

int photoresistor = A0; 

int power = A5; 

int analogvalue; 
int lightThreshold;

bool lightsOff = false;



void setup() {

    
    pinMode(photoresistor,INPUT);  
    pinMode(power,OUTPUT); 

    
    digitalWrite(power,HIGH);

    
    Particle.variable("analogvalue", &analogvalue, INT);
    

    lightThreshold = 40;
    
    analogvalue = analogRead(photoresistor);
    delay(1000);
    
    
    
  
}




void loop() {
   
  if (analogRead(photoresistor)<=lightThreshold) {
    Particle.publish("lights_off","intact");
        delay(1000);
        
       
    }

  else if (analogRead(photoresistor)>lightThreshold) {
       
        Particle.publish("lights_off","broken");
        delay(1000);
       
      }
   

}

Credits

Luke Lowry

1 project • 0 followers

Robert Jenkins

1 project • 0 followers

Light Up Your World