IDeATe

Outcome

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Context

This is the start point of building connected paired device.

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Intention

We want to make the linear actuator of device B response to the sensor of device A through Particle cloud webhook.

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Process

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【1】

At first, we follow the instruction and play with LED blink through web-hook.

(Make sure our web-hooks can work)

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bool doBlink = false;

// We will be using D2 to control our LED
int ledPin = D2;

// Our button wired to D0
int buttonPin = D3;

void setup()
{

  // For input, we define the
  // pushbutton as an input-pullup
  // this uses an internal pullup resistor
  // to manage consistent reads from the device

  pinMode( buttonPin , INPUT_PULLUP); // sets pin as input

  // We also want to use the LED

  pinMode( ledPin , OUTPUT ); // sets pin as output
	
	// blink the LED when the setup is complete
	blinkLED( 3, ledPin );
  
  Particle.subscribe( "blinkLED", handleActivateLED );

}

void loop()
{
   // find out if the button is pushed
   // or not by reading from it.
   int buttonState = digitalRead( buttonPin );

  // remember that we have wired the pushbutton to
  // ground and are using a pulldown resistor
  // that means, when the button is pushed,
  // we will get a LOW signal
  // when the button is not pushed we'll get a HIGH

  // let's use that to set our LED on or off

  if( buttonState == LOW )
  {
    // turn the LED On
    digitalWrite( ledPin, HIGH);
    Particle.publish( "doPairedPublish" );
		
  }else{
    // otherwise
    // turn the LED Off
    digitalWrite( ledPin, LOW);

  }
		delay( 1000 );



    if( doBlink == true ){
        blinkLED( 6, ledPin );
        doBlink = false;
    }


}

void blinkLED( int times, int pin ){
    
    for( int i = 0; i < times ; i++ ){
        digitalWrite( pin, HIGH );
        delay( 500 );
        digitalWrite( pin, LOW );
        delay( 500 );
    }
    
}

void handleActivateLED( const char *event, const char *data)
{
   doBlink = true;
}

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【2】

We replace the buttons as the sensors we are interested in in our circuit!

- QTR-1RC sensor

The sensor can detect the presence of objects in 3-9mm. We have to build special function related to time and duration to read the sensing data from it.

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int sensorPin = D3;
int ledPin = D2;

void setup() {
    pinMode(ledPin, OUTPUT);
    Particle.subscribe("blinkLED", handleActivateLED);
    blinkLED(3, ledPin);
}

unsigned long readQTR() {
    unsigned long duration = 0;
    pinMode(sensorPin, OUTPUT);
    digitalWrite(sensorPin, HIGH);
    delayMicroseconds(10);
    pinMode(sensorPin, INPUT);
    while(digitalRead(sensorPin) == HIGH) {
        duration++;
        if(duration > 3000) break;
    }
    return duration;
}

void loop() {
    unsigned long sensorValue = readQTR();
    if(sensorValue < 3000) {
        digitalWrite(ledPin, HIGH);
        Particle.publish("doPairedPublish");
    } else {
        digitalWrite(ledPin, LOW);
    }
    delay(100);
    if(doBlink) {
        blinkLED(6, ledPin);
        doBlink = false;
    }
}

void blinkLED( int times, int pin ){
    
    for( int i = 0; i < times ; i++ ){
        digitalWrite( pin, HIGH );
        delay( 500 );
        digitalWrite( pin, LOW );
        delay( 500 );
    }
    
}

void handleActivateLED( const char *event, const char *data)
{
   doBlink = true;
}

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【3】

We add linear actuator in our circuit. The LEDs are still kept to provide some clues for debugging as indicators.

- linear actuator, LA- T8-12-50-100/155-20,12V 50mm/s 100mm 20N 10% IP54

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bool doBlink = false;
int ledPin = D2;
int sensorPin = D3;
int buttonPin = D4;  // Button pin for manual retraction
bool isRetracting = false;  // Track retraction state

// L298N control pins
int enPin = A2;    // Enable pin for speed control
int in1 = D6;      // Direction control 1
int in2 = D7;      // Direction control 2

bool isBlinking = false;
int blinkCount = 0;
unsigned long lastBlinkTime = 0;

void setup() {
    pinMode(ledPin, OUTPUT);
    pinMode(enPin, OUTPUT);
    pinMode(in1, OUTPUT);
    pinMode(in2, OUTPUT);
    pinMode(buttonPin, INPUT_PULLUP);
    
    digitalWrite(in1, LOW);
    digitalWrite(in2, LOW);
    digitalWrite(enPin, HIGH);
    
    blinkLED(3, ledPin);
    Particle.subscribe("blinkLED", handleActivateLED);
}

unsigned long readQTR() {
    unsigned long duration = 0;
    pinMode(sensorPin, OUTPUT);
    digitalWrite(sensorPin, HIGH);
    delayMicroseconds(10);
    
    pinMode(sensorPin, INPUT);
    while(digitalRead(sensorPin) == HIGH && duration < 3000) {
        duration++;
    }
    return duration;
}

void actuatorExtend() {
    digitalWrite(in1, HIGH);
    digitalWrite(in2, LOW);
}

void actuatorRetract() {
    digitalWrite(in1, LOW);
    digitalWrite(in2, HIGH);
}

void actuatorStop() {
    digitalWrite(in1, LOW);
    digitalWrite(in2, LOW);
    analogWrite(enPin, 0);
}


void loop() {
    unsigned long currentMillis = millis();
    
    // Handle sensor and actuator control first
    if (!isRetracting) {
        unsigned long sensorValue = 0;
        for(int i = 0; i < 5; i++) {
            sensorValue += readQTR();
            delay(1);
        }
        sensorValue /= 5;

        if(sensorValue < 3000) {
            actuatorExtend();
            if (!isBlinking) digitalWrite(ledPin, HIGH);
            Particle.publish("doPairedPublish");
            // Remove delay here - it's interrupting actuator operation
        } else {
            if (!isBlinking) digitalWrite(ledPin, LOW);
            actuatorStop();
        }
    }

    // Handle button control
    if (digitalRead(buttonPin) == LOW) {
        isRetracting = true;
        actuatorRetract();
        if (!isBlinking) digitalWrite(ledPin, HIGH);
    } else if (isRetracting) {
        isRetracting = false;
        actuatorStop();
        if (!isBlinking) digitalWrite(ledPin, LOW);
    }
    
    // Handle LED blinking last
    if (doBlink && !isBlinking) {
        isBlinking = true;
        blinkCount = 0;
        lastBlinkTime = currentMillis;
    }
    
    if (isBlinking) {
        if (currentMillis - lastBlinkTime >= 500) {
            if (blinkCount >= 12) {
                isBlinking = false;
                doBlink = false;
                digitalWrite(ledPin, LOW);
            } else {
                digitalWrite(ledPin, !digitalRead(ledPin));
                lastBlinkTime = currentMillis;
                blinkCount++;
            }
        }
    }
    
    delay(10);
}


void blinkLED(int times, int pin) {
    for(int i = 0; i < times; i++) {
        digitalWrite(pin, HIGH);
        delay(500);
        digitalWrite(pin, LOW);
        delay(500);
    }
}

void handleActivateLED(const char *event, const char *data) {
    doBlink = true;
}

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