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# Lab_3 Report

last edited by 8 years, 2 months ago

PART A

a. How would you change the code to make the song play twice as fast?

int noteDuration = 500/noteDurations[thisNote];

b. What song is playing? ;-)

Star Wars

PART B

a. What voltage level do you need to power your display?

5V

b. What was one mistake you made when wiring up the display? How did you fix it?

I thought it wasn't working because I couldn't see but then I noticed that it was very dim and it was working well.

c. What line of code do you need to change to make it flash your name instead of "Hello World"?

lcd.print("Edgar");

PART C

1a. Post a copy of your new code in your lab writeup.

int sensorPin = A0;
int ledPin = 9;
int sensorValue = 0;

void setup() {
pinMode(ledPin, OUTPUT);
}

void loop() {
sensorValue = sensorValue/4;
analogWrite(ledPin, sensorValue);
}

2a. What resistance do you see with a Multimeter when the sensor is flat? When it is bent?

9.8K when is flat and 20.1K when is bent

2b. What kind of voltages should we expect for the Teensy analog pin based on the sensor resistance?

Using 3.3V and the sensor flat -> Vout = 22k/(9.8k+22k)*3.3V = 2.28V

Using 3.3V and the sensor bent -> Vout = 22k/(20.1k+22k)*3.3V = 1.72V

Using 5V and the sensor flat -> Vout = 22k/(9.8k+22k)*5V = 3.45V

Using 5V and the sensor bent -> Vout = 22k/(20.1k+22k)*5V = 2.61V

2c. How does the range of the LED's brightness change compared to the potentiometer?

It doesn't change because we have a higher resistance than 10K in the sensor

Not quite. The LED brightness will change as the resistance range is not the same.

Try doing a calculation.

2d. Include a copy of your Lowly Multimeter code in your lab write-up.

#include <LiquidCrystal.h>

LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

int sensorPin = A0;
int ledPin = 9;
int sensorValue = 0;
double outputValue = 0;

void setup() {
pinMode(ledPin, OUTPUT);
lcd.begin(16, 2);
}

void loop() {
outputValue = (double)sensorValue*5/1023; //convert sensorValue to voltage
analogWrite(ledPin, sensorValue);

//print in LCD
lcd.setCursor(0, 0);
lcd.print("Output value");
lcd.setCursor(0, 1);
lcd.print(outputValue);
}

3a. What resistance values do you see from your force sensor?

I see changes from M ohms to K ohms, depending on the force applied to the sensor (if more force is applied, the resistance decreases).

3b. What kind of relationship does the resistance have as a function of force applied? (e.g., linear?)

The resistance is inversely proportional to the force applied e.g., The resistance decreases when the force increases.

✓ Try going deeper and figure out the actual mathematical relationship. Hint: Check the datasheet.

3c. Include a copy of your FSR thumb wrestling code in your lab write-up.

#include <LiquidCrystal.h>

LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

int sensorPinLeft = A0;
int sensorPinRight = A1;
int sensorValueLeft = 0;
int sensorValueRight = 0;

void setup() {
lcd.begin(16, 2);
}

void loop() {

lcd.clear();

if(sensorValueLeft > sensorValueRight){
lcd.print("Left winning!");
}
if(sensorValueLeft < sensorValueRight){
lcd.print("Right winning!");
}

}

PART D

a. Make a short video showing how your timer works, and what happens when time is up!

b. Post a link to the Lab 3 Timers Hall of Fame.