Compile Error - Simple Help Needed

Troubleshooting
1

Hi Everyone,

I have put some code together that when a switch or button is pressed the spark core publishes a pressed state once only.
When released it publishes a released state, again once only.

When I compile is shows an error (iftttonce.cpp:25:1: error: expected unqualified-id before ‘else’)

Please can someone have a quick look and help me ?

int led = D0; // LED is connected to D0
int pushButton = D2; // Push button is connected to D2

bool button = false;

// This routine runs only once upon reset
void setup()
{
  pinMode(led, OUTPUT); // Initialize D0 pin as output
  pinMode(pushButton, INPUT_PULLUP);
  // Initialize D2 pin as input with an internal pull-up resistor
}

void loop()
{
  if (button == true) {
    digitalWrite(led, HIGH);  // Turn ON the LED
    Spark.publish("pushButtonState", "Pressed", 60, PRIVATE);
    button = false;

  }
  else {
  }
}

else {
  if (button == false) {
    Spark.publish("pushButtonState", "Released", 60, PRIVATE);

    button = true;
  }
  else {
  }
}
2

I could be mistaken, but I believe one of your curly brackets closes the loop() before the second ‘else’.
Furthermore, you aren’t doing anything with your button at the moment. It never reads the button, thus never uses its value.
Currently you’re in a false/true loop; you start with ‘false’ which publishes and sets it to ‘true’ which publishes and sets it to ‘false’, and repeat. That will push you over the publish limit instantly. Try implementing a button read, and make sure to debounce it.

1 Like
3

@Moors7 is correct, you’ve got one to many curly braces

For debouncing take a look at this Arduino article on the subject.

4

Thanks Guys, the Arduino article helps.

Re wrote using the article but only gives a toggle output of the LED and thats where I tried the

Spark.publish("pushButtonState","Pressed",60,PRIVATE);

What I am struggling to achieve is while ever the button is pressed 1 Spark.publish is sent. Then when the button is released 1 different Spark.publish is sent.
Any help is appreciated and the second attempt is below:

// constants won't change. They're used here to
// set pin numbers:
int buttonPin = D2;    // the number of the pushbutton pin
int ledPin = D0;      // the number of the LED pin

// Variables will change:
int ledState = HIGH;         // the current state of the output pin
int buttonState;             // the current reading from the input pin
int lastButtonState = LOW;   // the previous reading from the input pin

// the following variables are long's because the time, measured in miliseconds,
// will quickly become a bigger number than can be stored in an int.
long lastDebounceTime = 0;  // the last time the output pin was toggled
long debounceDelay = 50;    // the debounce time; increase if the output flickers

void setup() {
  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(ledPin, OUTPUT);

  // set initial LED state
  digitalWrite(ledPin, ledState);
}

void loop() {
  // read the state of the switch into a local variable:
  int reading = digitalRead(buttonPin);

  // check to see if you just pressed the button
  // (i.e. the input went from LOW to HIGH),  and you've waited
  // long enough since the last press to ignore any noise:

  // If the switch changed, due to noise or pressing:
  if (reading != lastButtonState) {
    // reset the debouncing timer
    lastDebounceTime = millis();
  }

  if ((millis() - lastDebounceTime) > debounceDelay) {
    // whatever the reading is at, it's been there for longer
    // than the debounce delay, so take it as the actual current state:

    // if the button state has changed:
    if (reading != buttonState) {
      buttonState = reading;

      // only toggle the LED if the new button state is HIGH
      if (buttonState == HIGH) {
        ledState = !ledState;
        Spark.publish("pushButtonState", "Pressed", 60, PRIVATE);
      }
    }
  }

  // set the LED:
  digitalWrite(ledPin, ledState);

  // save the reading.  Next time through the loop,
  // it'll be the lastButtonState:
  lastButtonState = reading;
}
5

You want to send a message on both sides of the button press…

something like this, perhaps (not tested)

#define DEBOUNCE_TIME 50

const int buttonPin = D2;
const int ledPin = D7;

int lastButtonState = HIGH;
unsigned long lastPressedTime = 0;  // the last time the output pin was toggled

void setup()
{
  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(ledPin, OUTPUT);
  digitalWrite(ledPin, LOW);
}

void loop()
{
  int buttonState = digitalRead(buttonPin);
  if (buttonState != lastButtonState)
  {
    if ((millis() - lastPressedTime) > DEBOUNCE_TIME)
    {
      lastPressedTime = millis();
      digitalWrite(ledPin, !buttonState);
      Spark.publish("pushButtonState", buttonState? "not pressed" : "pressed", 60, PRIVATE);
    }
  }
  lastButtonState = buttonState;
}
1 Like