IDeATe

Outcome

Using a pushbutton

Turn a light on and off using a pushbutton.

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//Practice exercise: Using a pushbotton

int ledPin = D2;

int buttonPin = D3;


void setup() {

    pinMode(ledPin,OUTPUT); //set pin as output
    
    pinMode(buttonPin, INPUT_PULLUP); //set pin as imput

}

void loop() {

    int buttonState = digitalRead(buttonPin);
    
    if(buttonState == LOW)
    {
        digitalWrite(ledPin,HIGH); //turn the led on
        
    }else{
        digitalWrite(ledPin,LOW); //otherwise turn the led off
    }
}

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Using a switch

Turning light on and off through a switch.

The code is the same as the pushbutton.

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//Practice exercise: Using a switch

int ledPin = D2;

int switchPin = D3;


void setup() {

    pinMode(ledPin,OUTPUT); //set pin as output
    
    pinMode(switchPin, INPUT_PULLUP); //set pin as imput

}

void loop() {

    int switchState = digitalRead(switchPin);
    
    if(switchState == LOW)
    {
        digitalWrite(ledPin,HIGH); //turn the led on
        
    }else{
        digitalWrite(ledPin,LOW); //otherwise turn the led off
    }
}

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Using a potentiometer

Fade up and down an LED as you turn the dial.

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//Practice exercise: Using a potentiometer

int potPin = A5;
int potReading = 0; //create a variable to hold the pot reading

int ledPin = D2;
int ledBrightness = 0; //create a variable to store the LED brightness


void setup() {

    pinMode(ledPin,OUTPUT); //set pin as output
    
    Spark.variable("pot", potReading ); //create a cloud variable of type integer
}

void loop() {
    
    //use analogRead to read the potentiometer reading
    //This gives us a value rom 0 to 4095
    
    potReading = analogRead(potPin); //0-4095
    
    
        
    //Map this value into the PWM range (0-255)
    //And store as the led brightness
    int ledBrightness = map(potReading,0,4095,0,255);
    
    //fade the LED to the desired brightness
    analogWrite(ledPin, ledBrightness ); //0-255


    //wait 1/10th of a second and then loop
    delay(100);
}

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Combining a switch and potentiometer

The switch should turn on and off the light while the potentiometer will fade up and down the light (but only when its on).

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//Exercise 1: Combine a switch and potentiometer.
//The switch should turn on and off the light while the potentiometer will fade up and down the light (but only when its on).

int potPin = A5;
int potReading = 0; //create a variable to hold the pot reading

int ledPin = D2;
int ledBrightness = 0; //create a variable to store the LED brightness

int switchPin = D3;


void setup() {

    pinMode(ledPin,OUTPUT); //set pin as output
    
    pinMode(switchPin,INPUT_PULLUP); //set pin as input
    
    Spark.variable("pot", potReading ); //create a cloud variable of type integer
}

void loop() {
    int switchState = digitalRead(switchPin);
    
    //use analogRead to read the potentiometer reading
    //This gives us a value rom 0 to 4095
    if (switchState == LOW)
    {
        digitalWrite(ledPin, HIGH);
        potReading = analogRead(potPin); //0-4095
    
        //Map this value into the PWM range (0-255)
        //And store as the led brightness
        int ledBrightness = map(potReading,0,4095,0,255);
    
        //fade the LED to the desired brightness
        analogWrite(ledPin, ledBrightness ); //0-255


        //wait 1/10th of a second and then loop
        delay(100);
    
    }else{
        digitalWrite(ledPin, LOW);
    }
}

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Using a photoresistor

The program shows how much light is available. When there is lots of light the LED is bright. When there is little light it’s dim.

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//Practice exercise: Using a photoresistor

int photoCellPin = A0;
int photoCellReading = 0; //create a variable to hold the light reading

int ledPin = D2;
int ledBrightness = 0; //create a variable to store the LED brightness

void setup() {

    //setup the LED for output
    pinMode(ledPin, OUTPUT);
    
    Particle.variable("light", &photoCellReading, INT); //create a cloud variable of type integer
    
}

void loop() {

    photoCellReading = analogRead(photoCellPin); //read the photo cell reading, 0-4095
    
    ledBrightness = map(photoCellReading, 0, 4095, 0, 255); //map this value into the PWM range (0-255) and store as led brightness

    analogWrite(ledPin, ledBrightness); //fade the led to the desired brightness
    
    delay(100); //wait 1/10th of a second and then loop
    
}

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Exercise 1:

Modify the program so that the LED shows the opposite. When there is little light, it will be bright and when there’s lots of light, it will be off.

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//Photoresistor exercise 1: 
//Modify the program so that the LED shows the opposite. When there is little light, it will be bright and when there’s lots of light, it will be off.

int photoCellPin = A0;
int photoCellReading = 0; //create a variable to hold the light reading


int ledPin = D2;
int ledBrightness = 0; //create a variable to store the LED brightness

void setup() {

    //setup the LED for output
    pinMode(ledPin, OUTPUT);
    
    
    Particle.variable("light", &photoCellReading, INT); //create a cloud variable of type integer
}

void loop() {

    
        digitalWrite(ledPin, HIGH);
        photoCellReading = analogRead(photoCellPin); //read the photo cell reading, 0-4095
        int ledBrightness = map(photoCellReading, 0, 4095, 255, 0); //map this value into the PWM range (0-255) and store as led brightness
       
        int lightreading = map (1500,0,4095,0,255);
        if(ledBrightness >= lightreading){
        
        analogWrite(ledPin, ledBrightness); //fade the led to the desired brightness
        }else{
            digitalWrite (ledPin, LOW);
        }
        delay(100); //wait 1/10th of a second and then loop
        
}

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Exercise 2:

Turn the light on and off when reaches certain levels. If the light levels are below 600 turn the light on (and bright), otherwise turn it off.

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//Photoresistor exercise 2: 
//Turn the light on and off when reaches certain levels.

int photoCellPin = A0;
int photoCellReading = 0; //create a variable to hold the light reading


int ledPin = D2;
int ledBrightness = 0; //create a variable to store the LED brightness

void setup() {

    //setup the LED for output
    pinMode(ledPin, OUTPUT);
    
    
    Particle.variable("light", &photoCellReading, INT); //create a cloud variable of type integer
}

void loop() {

    
        digitalWrite(ledPin, HIGH);
        photoCellReading = analogRead(photoCellPin); //read the photo cell reading, 0-4095
        int ledBrightness = map(photoCellReading, 0, 4095, 0, 255); //map this value into the PWM range (0-255) and store as led brightness
       
        int lightreading = map (600,0,4095,0,255);
        if(ledBrightness >= lightreading){
        
        analogWrite(ledPin, ledBrightness); //fade the led to the desired brightness
        }else{
            digitalWrite (ledPin, LOW);
        }
        delay(100); //wait 1/10th of a second and then loop
        
}

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Practice Exercise:

Combining Sensors and Inputs

In this exercise, I used a switch, photoresistor, and LED. The switch is controls the overall action of the LED light. LED and phtoresistor will only respond if the switch is switched on.

The scenario is for work lamp, which brightens up and dims down according to the existing light level in the room or daylight. But it will only work when the switch is on.

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//Practice Exercise: 
//Combining Sensors and Inputs

int photoCellPin = A0;
int photoCellReading = 0; //create a variable to hold the light reading


int switchPin = D3;
int switchState;


int ledPin = D2;
int ledBrightness = 0; //create a variable to store the LED brightness

void setup() {

    //setup the LED for output
    pinMode(ledPin, OUTPUT);
    pinMode(switchPin,INPUT_PULLUP);
    
    Particle.variable("light", &photoCellReading, INT); //create a cloud variable of type integer
    
}

void loop() {
        
        switchState = digitalRead(switchPin);
        photoCellReading = analogRead(photoCellPin); //read the photo cell reading, 0-4095
        
        ledBrightness = map(photoCellReading, 0, 2500, 255, 0); //map this value into the PWM range (0-255) and store as led brightness
        //int lightreading = map (500,0,4095,255,0);
        
    if(switchState == LOW)
    {
        //digitalWrite (ledPin, HIGH);
        
        analogWrite(ledPin, ledBrightness); //fade the led to the desired brightness
        
        }else if(switchState == HIGH){
            digitalWrite (ledPin, LOW);
        }else {digitalWrite (ledPin, LOW);
        }
        delay(100);
        
}

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Process & Reflections

I started out with one input or sensor one a time, and then add on to it another input. This helped me to understand how the circuit works on the breadboard.

Relating the photoresistor reading value (0-4095) and the PWM range (0-255) to the actual brightness seen through human eyes, was an odd process for me. It took a few try outs to see what it actually looks like by trying out different values and checking the reading from Particle Console. The photoresistor sensor also seems a bit unstable with instances where LED brightness not reacting or reacting slowly.

Overall, I think I gained better understanding in how the circuit works on the breadboard. And it was nice to imagine how the prototype relates to the real world.

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Outcome

Using a pushbutton

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Using a switch

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Using a potentiometer

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Combining a switch and potentiometer

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Using a photoresistor

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Exercise 1:

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Exercise 2:

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Practice Exercise:

Combining Sensors and Inputs

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Process & Reflections