Swich Case with nested if statement problems

Projects General Guidance
1

I have a sketch set up to run switch case statement base on voltage of a potentiometer. I have it set so case 0 has an if statement to light up LED's if the button is pressed. For some reason the LED flicker on every 6 seconds or so and then turn back off even when nothing is attached to A5(the pin going to the button). If I change the potentiometer to the highest voltage the LEDS don't light up. I am not sure how it is getting an analog reading even when no cable is plugged into the A5 pin. Also, when the LEDs are off I can push the button and they turn on, as soon as I let got they turn off again. This is very odd, any ideas?

Here is the code

const int sensorMin = 0;      // sensor minimum, discovered through experiment
const int sensorMax = 1023;    // sensor maximum, discovered through experiment
const int pentometerPin = A0;// pin that the pentometer is attached to
const int buttonApin = A5; // pin that the button is attached to
const int ledPin = 8;
const int ledPin2 = 9;

void setup() {
  pinMode(ledPin, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  pinMode(buttonApin, INPUT);
  // initialize serial communication:
  Serial.begin(9600);  
}

void loop() {
  // read the sensor:
  int sensorReading = analogRead(A0);
  int buttonstate = analogRead(buttonApin);
  // map the sensor range to a range of four options:
  int range = map(sensorReading, sensorMin, sensorMax, 0, 6);

  // do something different depending on the 
  // range value:
  switch (range) {
  case 0:
    if(buttonstate == LOW)
    {
      digitalWrite(ledPin, HIGH);
      digitalWrite(ledPin2, HIGH);
      Serial.println("Button Pressed");
    }
    else
    {
      digitalWrite(ledPin, LOW);
      digitalWrite(ledPin2, LOW); 
    }
      // your hand is on the sensor
    Serial.println("lowest");
    break;
  case 1:    // your hand is close to the sensor
    Serial.println("lower");
    break;
  case 2:    // your hand is a few inches from the sensor
    Serial.println("low");
    break;
  case 3:    // your hand is nowhere near the sensor
    Serial.println("medium");
    break;
  case 4:
    Serial.println("high");
     break;
  case 5:
     Serial.println("higher");
     break;
   case 6:
   Serial.println("highest");
   break;
  } 
  delay(1);        // delay in between reads for stability
}

Here is the layout: 1 item

2

OMG ... Quick before one of the old-guard fusses... Edit to include CODE TAGS before-after your code :fearful:

Like thus:

// Hint: it us the # symbol on the toolbar.

...
...

3

Ohh, didn't know that was a thing. Fixed it

4

So, which is the desired behavior?

I guess you miss a pull up resistor, it needs to bee in the button:

5

It is supposed to only light the LEDs when I push the button. How ever the LEDS light up even when there is nothing on the A5 pin. I can literally remove the cable from the arduino and it still lights the LEDs up randomly. I have changed the A5 from INPUT to INTPUT_PULLUP but then nothing happens. Wont light up period

6

you need to put a 10k resistor from vcc to the A5, the same pin which has the button, check this picture (3):

520×840 66.1 KB

7

Change this line
pinMode(buttonApin, INPUT);

pinMode(buttonApin, INPUT_PULLUP); // input with internal pullup enabled

Wire the button to connect to Gnd when pressed.
Then:

const int buttonApin = 19; // pin that the button is attached to - A5 = D19
int buttonstate = digitalRead(buttonApin);

8

CrossRoads:
Change this line
pinMode(buttonApin, INPUT);

pinMode(buttonApin, INPUT_PULLUP); // input with internal pullup enabled

Wire the button to connect to Gnd when pressed.
Then:

const int buttonApin = 19; // pin that the button is attached to - A5 = D19
int buttonstate = digitalRead(buttonApin);

That works! I know its a bit much to ask but can you explain why it works? Does digital read not float or something? Does INPUT_PULLUP only work with digital read?

Also, if you happen to know a good tutorial on pull up resistors that would be awesome. They seem to be important, and I can't find a decent guide(or haven't yet anyways)

9

"tutorial on pull up resistors" Huh? Just enable them to hold the pin at a steady HIGH when not grounded.

I think it works because this
int buttonstate = analogRead(buttonApin);
returns a value of 0-1023, and you were checking for
buttonstate == LOW,
which doesn't really make sense.
digitalRead looks for HIGH, LOW, so that makes more sense.