Excercise 5

Analog Input/Output

Part 1

This part of the exercise is straightforward. I simply copied and pasted the code into the Arduino environment and wired my breadboard according to the fritzing schematic. I do not see where I needed to modify the code or the fritzing schematics. I just followed the directions and got the results I expected; a flashing led who's pulse rate is variable based on the value of the potentiometer. This is the code I used:

int sensorPin = A0;      // variable for analog pin (specified as A0-A5)

int sensorValue = 0;     // variable to read sensor value

int ledPin = 13;         // change LED blink rate based on sensor input!



void setup() {

  pinMode(ledPin, OUTPUT);

}



void loop() {

  

  // read the sensor's value (0-1023**)

  sensorValue = analogRead(sensorPin);

  

  // set the LED's blink to the sensor value

  digitalWrite(ledPin, HIGH);

  delay(sensorValue);

  digitalWrite(ledPin, LOW);

  delay(sensorValue);

}

Part 2

When I opened the fritzing schematic, I noticed that it required a FSR (force sensitive resistor). I do not have one included in my kit, so i decided to just leave the additional sensor out of my circuit. this is the code that I wrote for this circuit:

int potPin = 1;

int potpin2 = 0;
int ledPin = 10;
int ledpin2 = 11;
int val = 0; 

void setup() {
pinMode(ledPin, OUTPUT);
pinMode(ledpin2, OUTPUT);  
}
void loop() {
  val = analogRead(potPin);   
  digitalWrite(ledPin, HIGH);  
  delay(val);                 
  digitalWrite(ledPin, LOW);   
  delay(val);   
  val = analogRead(potpin2);
 digitalWrite(ledpin2, HIGH);  
  delay(val);                  
  digitalWrite(ledpin2, LOW);   
  delay(val);    
}

The leds would blink back and forth. However when I obstructed the photoresistor or turned the potentiometer knob, the green led would react by blinking more frequently. I was unsure how to make the other led blink more on it's own. I believed that because I was using a 10k ohm potentiometer instead of a 100k ohm as specified in the fritzing diagram resulted in the more frequent blinking of the green led. Things are feeling a bit hazy for me. Not exactly sure what the result should be. I understand that the diagram is highlighting three different types of voltage divider, but I am unclear as to what the final result should look like. 

Part 3

I opened the fade example and took what I learned from parts one and two to write my code:

int led = 10;

int led2 = 11;
int brightness = 0;    
int fadeAmount = 5; 
int val = 0;
int potpin = 0;
int potpin2 = 1;

void setup()  { 
  pinMode(potpin, INPUT);
  pinMode(potpin2, INPUT);
  
  pinMode(led, OUTPUT);
  pinMode(led2, OUTPUT);
} 
void loop()  { 
  val = analogRead(potpin);
  val = analogRead(potpin2);
  analogWrite(led, brightness);
  analogWrite(led2, brightness);  

  brightness = brightness + fadeAmount;

  if (brightness == 500n || brightness == 100) {
    fadeAmount = -fadeAmount ; 
  }     
  delay(30);                            
}

I ran into a few problems. The main problem is that there was no variability in the fade rates of my leds. I tried adjusting the sensor values as suggested in the exercise, but I noticed little change. The leds blinked simultaneously instead of one after the other. I do not know if this has something to do with the dissonance between the analog ports and the digital ports. Because I could not figure out what was wrong with my code and/or circuit, I was unable to apply the low bipass filter to modify the fading. 

Unlike the last few exercises in which I understood completely, I am beginning to get lost. I understand the objective of each exercise, however I am having trouble reaching that objective. I think that the directions are unclear and there are no examples of what my end product should look like. I am a visual learner and I tend to get lost in abstract concepts. I think a demonstration would help me understand things a bit better so that I can move on to part 4.