Published December 4, 2020

IoT Light Strip

Learn how to set up a light-sensitive LED Strip using only 2 Particle Argon Kits and an Individually Programmable LED Strip!

IntermediateFull instructions provided7 hours1,132

Things used in this project

Hardware components

Particle Argon Kit

Individually Addressable LED Strip

Jumper wires (generic)

Story

Introduction

If you've ever had any interest in how to control an Individually Programmable LED Strip with a Particle Argon you've come to the right place!

This story includes a COMPLETE guide on how to set up the project and is aimed to leave you with all the information you need to get started with your own Argon controlled Individually Programmable LED Strip!

For this project specifically we will be using 2 Particle Argons, communicating data between each other, in order to display an output on the Individually Programmable LED Strip.

1 / 2 • Figure 1. Argon Light Sensor (FIRST)

The FIRST Argon will be individually set up and calibrated as a light-sensor
The SECOND Argon will be wired to the LED Strip to read incoming data and control the visual output of the Strip

With both of your Particle Argon's set up and connected to the cloud, you're ready to begin!

Set Up

*Light Sensor*

Figure 3. Argon Light Sensor

Start with the first Argon which is going to be used as a light sensor. This will be done using the materials included with the Argon as well as an additional jumper wire or any working alternative.

Included in the Particle Argon Kit, you should have:

1 Single Red LED
2 Resistors
1 Photo-Resistor

With the Argon disconnected from power you can begin constructing the circuit as shown below in Figure 4. Light Sensor Schematic.

Figure 4. Light Sensor Schematic

The Red LED will be wired from the A5 pin on the Argon to any ground node on your breadboard. This will be used as an output to display a change in the data input.

The Photo-Resistor will be wired from the A0 pin to any node in the same column but ensuring it is not connected to any of the Argon's other pins as shown in the figure above. This allows the Photo-Resistor to capture light data and display a reading through the LED light or in other words, as the Photo-Resistor detects light the LED will be off but as soon as an absence of light is detected the Red LED will switch on.

2 resistors will be used as buffers in the circuit between the Photo-Resistor and the Red LED. These are wired just as shown in the schematic above and this completes the set up of the light sensor.

*LED Strip + Argon*

Figure 5. LED Strip Argon w/ Power Supply

To assemble the next component grab the light strip (WS2812B), the remaining Argon, 2 extra jumper wires and again, make sure the Argon is disconnected from power before proceeding.

For a simple schematic of this component refer to Figure 6. LED Strip + Argon Schematic shown below.

Figure 6. LED Strip + Argon Schematic

The strip contains 3 important wires:

Data = Green Colored Wire

Ground = White Colored Wire

Power = Separate Red & White Colored Wire

The green colored data wire on the light strip will be connected from the light strip to the D2 pin on the Argon which will allow us to feed data into the LED's using the connected Argon.

The ground connection, or white colored wire from the light strip will be connected to the GROUND Pin on the Argon.

The red & white colored wires for power, indicating power and ground respectively, have been connected directly from the light strip to a USB Wall Adapter supplying +/- 5 volts.

With both of the components assembled and powered on, all that is left is the code to get the devices behaving correctly in the presence as well as absence of light. Refer to the code we have provided to get the project up and running instantly or feel free to expand on it using the pointers given in the comments to create your own unique patterns or change the way in which the Argons behave.

The Youtube video below provides a quick demonstration of this project in action!

IOT Project Demonstration

Real Time Data:

The figure below represents the project after running for one full day. A "1" is received when there is no light detected and "0" when it has detected an adequate amount of light.

Google Sheets Plot of LED Strip/Light Sensor Data

Conclusion

This was a very exciting experiment with various tools and gadgets that my partner and I have never had the chance to try out until now. Throughout the course of this project we have already managed to gather a handful of new ideas to implement with different IoT devices. We hope this inspires you to create your own project and explore everything thats possible with IoT devices.

Code

//LED light connected to A5 and ground 
int led1 = A5; 

//LED on the Argon 
int led2 = D7; 

//Photoresistor connected to A0 pin that detects light 
int photoresistor = A0;
int analogValue;

void setup() {

  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(photoresistor, INPUT);

}

//Loop constructed to read analog value of the photoresistor and digital 
//write to the LEDs in the circuit. Particle.publish is used twice to publish 
//an event both when light is detected and when it is not. 
void loop() {
    analogValue = analogRead(photoresistor);
    
//if statement below can be changed to adjust how sensitive the photoresistor is to light
    if (analogValue > 15) {
        digitalWrite(led1, LOW);
        digitalWrite(led2, LOW);
        Particle.publish("LED-OFF", "0", PUBLIC);
        delay(7000);
    } else {
        digitalWrite(led1, HIGH);
        digitalWrite(led2, HIGH);
        Particle.publish("LEDON", "1", PUBLIC);
        delay(7000);
    }
}

#include "Particle.h"
#include "neopixel.h" 

// IMPORTANT: Set pixel COUNT, PIN and TYPE
#define PIXEL_PIN D2
#define PIXEL_COUNT 300
#define PIXEL_TYPE WS2812B

Adafruit_NeoPixel strip(PIXEL_COUNT, PIXEL_PIN, PIXEL_TYPE);

//Defines the color chase pattern 
void colorChase(uint32_t c, uint8_t wait) {
    int i;
    
    for (i=0; i<strip.numPixels()+10; i++) strip.setPixelColor(i, 0); 
    
    for (i=0; i<strip.numPixels(); i++) {
        strip.setPixelColor(i, c);
        strip.show();
        strip.setPixelColor(i-10, 0);
        delay(wait);
    }
    
    strip.show();
}


//Defines the color all pattern(makes whole strip one color)
void colorAll(uint32_t c, uint8_t wait) {
  uint16_t i;

  for(i=0; i<strip.numPixels(); i++) {
    strip.setPixelColor(i, c);
  }
  strip.show();
  delay(wait);
}

//Defines the color wipe pattern 
void colorWipe(uint32_t c, uint8_t wait) {
    int i;
    
    for (i=0; i<strip.numPixels(); i++) strip.setPixelColor(i, 0);    
    
    for(uint16_t i=0; i<strip.numPixels(); i++) {
        strip.setPixelColor(i, c);
        strip.show();
        delay(wait);
  }
}

void setup() {
    
//Subscribes to the two published events from the Argon with the light sensor
    Particle.subscribe("LEDON", myHandler, MY_DEVICES);
    Particle.subscribe("LED-OFF", Handler, MY_DEVICES);
    strip.begin();
    strip.show();
}


//Handler function for when light IS NOT detected
void myHandler(const char *event, const char *data) {
    
    Serial.print(event);
    Serial.print(", data: ");
    
    if (data = "1") {
        colorWipe(strip.Color(255, 255, 0), 5);
        delay(1000);
    }

 }

//Handler function for when light IS detected 
void Handler(const char *event, const char *data) {
    
    Serial.print(event);
    Serial.print(", data: ");
    
    if (data = "0") {
        colorChase(strip.Color(0, 0, 0), 10);
        delay(1000);
    }

 }

//Can be used for continuous loop without being connected to the light sensor
//void loop() {
    
    //colorWipe(strip.Color(255, 255, 255), 5);
    
    //colorChase(strip.Color(255, 0, 255), 5);
 
    //colorChase(strip.Color(0, 255, 255), 5);
     
    //colorChase(strip.Color(255, 255, 0), 5);
     
    //colorWipe(strip.Color(0, 255, 255), 5);

    
//}

Credits

David Varblane

1 project • 0 followers

Matthew Zotsman

1 project • 0 followers

IoT Light Strip