Skills Dev2 : Rahul Jha

Outcome

simple 2-inputs (sensors or inputs) 1-output (LED) device - representing automatic lights on/off (and dimming) system based on the natural light intensity in a room
Inputs: Photosensor (photo-resistor), Toggle Switch
Output: Led
Overall idea: to implement an automatic light on/off system using natural light intensity. Here the photosensor will sense the intensity of natural light in the room. As the intensity of natural light changes, the LED output intensity will change. The master toggle switch will provide overall control of the system. It provides an option to keep the system automatic or manual. When the toggle switch is ON, then only, output LED can be controlled using this system.

Process

1. Initially connected an LED to the argon board and connected it at D2 pin.
2. Next wired photo sensor on the board using a pull-down resistor of 10 K ohm and connected it to A4 pin.
3. Developed the sketch (program ) to simply control the LED intensity with the corresponding change in the intensity of light falling on the photosensor.
4. Shared the value of photosensor online using 'particle.variable'.

Code for : photo-resistor as sensor input and LED as output

int ledPin = D2;

int photoresPin = A4;
int photoresRead = 0;

void setup() {
    
    //Set the LED as Output
    pinMode(ledPin, OUTPUT);
    
   
    
    Particle.variable("photoResValue", photoresRead);
    
}

void loop() {
    
    //0-4095
    photoresRead = analogRead(photoresPin);
    
    //using map function to convert the range
    int brightness = map(photoresRead, 0 , 4095, 0, 255 );
    
    analogWrite( ledPin, brightness );
    
    delay(200);
    
 }

Click to Expand

Link for youtube video (photo-resistor as sensor input and LED as output):

https://youtu.be/kbJwn5DyKzE

SkellDev2-1

rahuljha89 - https://youtu.be/kbJwn5DyKzE

5. Added third component - toggle switch to the circuit. It controls the overall functionality, that is when the switch is ON then only, LED can be switched ON. Aalso published the switch ON/OFF events on the particle cloud.

Code after adding second input - toggle switch:

int ledPin = D2;
int switchPin = D4;
int switchState; //store the reading from the button 
int switchState_prev = LOW;

int photoresPin = A4;
int photoresRead = 0;

void setup() {
    
    //Set the LED as Output
    pinMode(ledPin, OUTPUT);
    
    //Set the switch as input
    pinMode (switchPin, INPUT_PULLUP); 
    
    Particle.variable("photoResValue", photoresRead);
    
}

void loop() {
    
    switchState = digitalRead( switchPin );
    
    
    if(switchState == HIGH){
        
        
        // added the below code to make sure publish happens only when..
        // switch state changes from previous state
        if (switchState != switchState_prev){
            Particle.publish( "Switch ON" );
        }
        switchState_prev = switchState;
        
        //0-4095
         photoresRead = analogRead(photoresPin);
    
        //using map function to convert the range
        int brightness = map(photoresRead, 0 , 4095, 0, 255 );
    
        analogWrite( ledPin, brightness );
    
        delay(200);
    
    }else{
        
        if (switchState != switchState_prev){
             Particle.publish( "Switch OFF" );
        }
        switchState_prev = switchState;
        
        
        int brightness = 0;
        analogWrite( ledPin, brightness );
        
    }

}

Click to Expand

Link for youtube video (after adding third component: second input - toggle switch):
https://youtu.be/Ky0jvFmMy0k