IDeATe

Outcome

Using a pushbutton

Turn a light on and off using a pushbutton.

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int ledPin = D2;
int buttonPin = D3;

void setup() {
    pinMode(ledPin, OUTPUT); // set as an output
    pinMode(buttonPin, INPUT_PULLUP); // set as an input
}

void loop() {
    int buttonStatus = digitalRead(buttonPin);
    if (buttonStatus == LOW){ // when the button is pressed
        digitalWrite(ledPin, HIGH); //turn the light on
    }else{
        digitalWrite(ledPin, LOW); // if not, turn the light off
    }
}

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Using a switch

Turning light on and off through a switch.

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int ledPin = D2;
int switchPin = D3;

void setup() {
    pinMode(ledPin, OUTPUT); // set as an output
    pinMode(switchPin, INPUT_PULLUP); // set as an input
}

void loop() {
    int buttonStatus = digitalRead(switchPin);
    if (buttonStatus == LOW){ // when the switch is turned on
        digitalWrite(ledPin, HIGH); //turn the light on
    }else{
        digitalWrite(ledPin, LOW); // if not, turn the light off
    }
}

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Using a potentiometer

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

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int potPin = A5;
int potRead = 0;
int ledPin = D2;
int ledBright = 0;

void setup() {
    pinMode(ledPin, OUTPUT);
    Particle.variable("pot", potRead);
}

void loop() {
    potRead = analogRead(potPin);
    // change the range of potRead
    ledBright = map(potRead, 0, 4095, 0, 255);
    analogWrite(ledPin, ledBright);
}

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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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int potPin = A5;
int potRead = 0;
int ledPin = D2;
int ledBright = 0;
int switchPin = D3;

void setup() {
    pinMode(ledPin, OUTPUT);
    pinMode(switchPin, INPUT_PULLUP);
    Particle.variable("pot", potRead);
    Particle.variable("led", ledBright);
}

void loop() {
    int switchStatus = digitalRead(switchPin);
    if (switchStatus == LOW){ // if turning on the switch
        potRead = analogRead(potPin);
        // change the range of potRead
        ledBright = map(potRead, 0, 4095, 0, 255);
        analogWrite(ledPin, ledBright);
    }else{ // if turning off the switch
        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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int ledPin = D2;
int sensorPin = A0;
int lightRead = 0;
int ledBright = 0;

void setup() {
    pinMode(ledPin, OUTPUT);
    Particle.variable("light", lightRead);
    Particle.variable("led", ledBright);
}

void loop() {
    lightRead = analogRead(sensorPin); // read the lightResister
    ledBright = 255 - map(lightRead, 0, 4095, 0, 255);
    analogWrite(ledPin, ledBright); // if the light is brighter, the LED light is stonger
}

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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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int ledPin = D2;
int sensorPin = A0;
int lightRead = 0;
int ledBright = 0;

void setup() {
    pinMode(ledPin, OUTPUT);
    Particle.variable("light", lightRead);
    Particle.variable("led", ledBright);
}

void loop() {
    lightRead = analogRead(sensorPin); // read the lightResister
    ledBright = map(lightRead, 0, 4095, 0, 255);
    analogWrite(ledPin, ledBright); // if there is lots of light, the LED is dim
}

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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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int ledPin = D2;
int sensorPin = A0;
int lightRead = 0;
int ledBright = 0;
int lightResist = 0;

void setup() {
    pinMode(ledPin, OUTPUT);
    Particle.variable("light", lightRead);
    Particle.variable("led", ledBright);
}

void loop() {
    lightRead = 4095 - analogRead(sensorPin); // read the light
    lightResist = analogRead(sensorPin);
    if(lightRead < 600){
        ledBright = map(lightResist, 0, 4095, 0, 255);
        analogWrite(ledPin, ledBright); 
    }else{
        digitalWrite(ledPin, LOW);
    }
}

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Practice Exercise:

if the button is pressed: the led will react with the lightness of outside world

The stronger the outside light is, the weaker the light intensity of LED will be

If the button is not pressed, nothing will happen

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int led1 = D2;
int button1 = D3;
int buttonState;
int lightSensor1 = A0;
int lightRead = 0;
int ledLighting = 0;

void setup() {
    
    pinMode(led1, OUTPUT);
    pinMode(button1, INPUT_PULLUP);
    Particle.variable("light", lightRead);
    Particle.variable("LEDbrightness", ledLighting);
    
}

void loop() {
    buttonState = digitalRead(button1);
    lightRead = analogRead(lightSensor1); //0-4095
    
    // if the button is pressed: the led will react with the lightness of outside world
    // the stronger the outside light is, the weaker the light intensity of LED will be 
    // if the button is not pressed, nothing will happen
    
    if (buttonState == LOW){
        ledLighting = 255 - map(lightRead, 0, 4095, 0, 255); //0-255
        analogWrite(led1, ledLighting);
    }else{
        digitalWrite(led1, LOW);
    }
    }

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Process & Reflections

I think it's very interesting to understand how sensors and controllers work. One thing is important is to know the difference between analogRead/Write and digitalRead/Write. There is no such method as digitalRead but we set pinMode to do that. By thinking about we need a boolean value or a value in range, I'm more confident with writing codes. By the way, map() is a good method to change value range. And remembering the electrical connection of all kinds of sensors and controllers is really important!

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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:

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Process & Reflections