a. How would you change the code to make the song play twice as fast?
I would modify line 35 to:
int noteDuration = 500/noteDurations[thisNote];
By dividing 500 by the duration instead of 1000 by the duration, the time each note is played (and by virtue of lines 40&41 the time between the notes) and will be reduced by half.
b. What song is playing? ;-)
The Star Wars main theme is played.
b. What was one mistake you made when wiring up the display? How did you fix it?
When I first placed the LCD, I didn't leave enough room to put the potentiometer in the place I wanted. (I have a strong sense of wiring feng shui). So I had to move it over, and move the two power/ground wires that I already placed.
c. What line of code do you need to change to make it flash your name instead of "Hello World"?
lcd.print("hello, world!"); needs to be replaced with lcd.print("Harry"); Note that when I wired the LCD, I used a different set of wiring than was included in the original schematic. So I also had to change the initialization line as well.
a. Post a copy of your new code in your lab writeup.
void loop() {
// read the value from the sensor:
sensorValue = analogRead(sensorPin);
analogWrite(13, sensorValue>>2); //analogWrite uses 0-255, analogRead uses 0-1023. Need to divide by four, it's faster to shift right by two.
delay(50);
}
a. What resistance do you see with a Multimeter when the sensor is flat? When it is bent?
Flat: 24K
Bent: 50K
b. What kind of voltages should we expect for the Arduino analog pin based on the sensor resistance?
Flat: 2.5V
Bent: (24/(24+50))*5V = 1.62V
c. How does the range of the LED's brightness change compared to the potentiometer?
Drastically reduced range.
#include <LiquidCrystal.h>
int oldSensorVal = 0;
int sensorVal = 0;
int ledPin = 13;
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(8, 7, 12, 11, 10, 9);
void setup() {
pinMode(A0, INPUT);
pinMode(ledPin, OUTPUT);
// set up the LCD's number of columns and rows:
lcd.begin(16, 2);
// Print a message to the LCD.
lcd.print("hello, world!");
}
void loop() {
// set the cursor to column 0, line 1
// (note: line 1 is the second row, since counting begins with 0):
lcd.setCursor(0, 1);
oldSensorVal = sensorVal; //for comparison
sensorVal = analogRead(0); //new sensor value.
if(oldSensorVal != sensorVal) { //only print if there's a new value.
lcd.print(" "); //clear the appropriate section (faster than having to clear the entire screen)
lcd.setCursor(0, 1);
lcd.print(sensorVal);
}
analogWrite(13, map(sensorVal, 350, 550, 0, 255)); //non-flexed to flexed seems to range 350 - 550. Map this to LED being off-on.
delay(50);
}
a. What resistance values do you see from your force sensor?
0.3K-70K
b. What kind of relationship does the resistance have as a function of force applied? (e.g., linear?)
After the initial drop from infinite impedance, it is an inversely proportional linear relationship.
c. Include a copy of your FSR thumb wrestling code in your lab write-up
#include <LiquidCrystal.h>
int oldSensorVal = 0;
int sensorVal = 0;
int ledPin = 13;
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(8, 7, 12, 11, 10, 9);
void setup() {
pinMode(A0, INPUT);
pinMode(ledPin, OUTPUT);
// set up the LCD's number of columns and rows:
lcd.begin(16, 2);
// Print a message to the LCD.
lcd.print("Thumb Wrestling!");
}
void loop() {
// set the cursor to column 0, line 1
// (note: line 1 is the second row, since counting begins with 0):
lcd.setCursor(0, 1);
sensorVal = analogRead(0); //new sensor value.
lcd.setCursor(map(sensorVal, 0, 1023, 15, 0 ), 1); //Print a # at the appropriate point based on who is winning. (0 = right team winning, 1023 = left team winning).
lcd.print("#");
delay(50);
lcd.setCursor(map(sensorVal, 0, 1023, 15, 0 ), 1); //Clear the character.
lcd.print(" ");
}
Thumb Wrestling/Timer!
/*
ThumbWrestling.ino
Harry Johnson
Stanford University EE47, Spring 2012-2013
Implements a thumb wrestling game with two force sensors, a button, an LCD, and a speaker.
The game pits two players against each other to see who can squeeze the flex sensor harder.
It waits for a button press to start the game. During the game's operation, the LCD displays the current prospective winner,
how long they need to hold on for to win, and a graphical representation of the current balance.
The two force gauges are used as a voltage divider.
5V -> 4.7K (current limit) -> Gauge 1 -> Gauge 2 -> 4.7K -> GND.
*/
#include <LiquidCrystal.h>
const int soundPin = 6; //speaker on pin 6
const int buttonPin = 2; //button on pin 2.
const int timeout = 5; //5 seconds in one state = win.
long int startTime; //startTime is refreshed with current millis() value on each "turnover" between one team winning and another.
long int curTime; //curTime is how many seconds are left until the current team wins.
int sensorVal = 0;
int gameState = 0; // State of game.
//0: not started
//1: Player 1 winning
//2: Player 2 winning
//3: Celebrating player 1!
//4: Celebrating player 2!
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(8, 7, 12, 11, 10, 9);
void setup() {
pinMode(A0, INPUT);
pinMode(soundPin, OUTPUT);
pinMode(buttonPin, INPUT);
digitalWrite(buttonPin, HIGH); //enable internal pullups.
// set up the LCD's number of columns and rows:
lcd.begin(16, 2);
// Print a message to the LCD.
}
void loop() {
sensorVal = analogRead(0); //new sensor value.
lcd.setCursor(0, 0);
lcd.print(" "); //clear first line of display
lcd.setCursor(0, 0);
switch(gameState) {
case 0: gameState = state_zero(); break; //next state generated by return of current state.
case 1: gameState = state_one(); break;
case 2: gameState = state_two(); break;
case 3: gameState = state_three(); break;
case 4: gameState = state_four(); break;
}
lcd.setCursor(0, 0);
delay(50);
}
int state_zero() {
lcd.print("Button To Start");
lcd.setCursor(0,1);
lcd.print(" "); //clear second line of display
if(digitalRead(buttonPin) == LOW) return 1;
return 0;
}
int state_one() { //Player one is winning.
curTime = timeout - (millis() - startTime)/1000; //curTime represents how long the person has to hold on for by subtracting the delta-T since a turnover from the time required to win.
lcd.print("Team 1 wins in ");
lcd.print(curTime);
if(curTime == 0) return 3; //KO, team one has won!
displayMeter(sensorVal); //graphical display on line two.
if(sensorVal < 511) { //if team two has beaten team one, switch to the state of team two winning.
startTime = millis();
return 2;
}
return 1;
}
int state_two() { //player two is winning.
curTime = timeout - (millis() - startTime)/1000;
lcd.print("Team 2 wins in ");
lcd.print(curTime);
if(curTime == 0) return 4; //KO, team two has won!
displayMeter(sensorVal);
if(sensorVal > 511) { //if team one has beaten team two, switch.
startTime = millis();
return 1;
}
return 2;
}
int state_three() { //player one has won.
lcd.print("Team One Wins!");
tone(soundPin, 147, 1000);
delay(4000);
return 0;
}
int state_four() { //player two has won.
lcd.print("Team Two Wins!");
tone(soundPin, 147, 1000);
delay(4000);
return 0;
}
void displayMeter(int val) { //takes a val from 0-1023 and
lcd.setCursor(map(val, 0, 1023, 15, 0 ), 1); //Print a # at the appropriate point based on who is winning. (0 = right team winning, 1023 = left team winning).
lcd.print("#");
delay(50);
lcd.setCursor(map(val, 0, 1023, 15, 0 ), 1); //Clear the character.
lcd.print(" ");
}
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