UNIVERSITY OF PENNSYLVANIA
DEPARTMENT OF ELECTRICAL ENGINEERING
ESE UNDERGRADUATE LABORATORY
ESE 205: Electrical Circuits and Systems I Laboratory
Self-timer and Musical Notes using the Arduino Board
Goal:
1. To use the Arduino Board as a self-timer.
a. The LCD display interfaced to the Arduino board
should display the countdown time.
b. The buzzer should go off when the timer countdown reaches zero.
2. To play musical notes using the buzzer interfaced with the Arduino board.
3. Extra Credit: Use the self timer mode to play musical notes.
Parts Required
1.
2.
3.
4.
5.
Arduino Board
USB Cable
Sound Buzzer (32S4120)
16X2 LCD Display
Wires
Procedure:
a. Build the sound buzzer circuit as shown in Figure 1
Figure 1: Sound Buzzer Circuit
Figure 2: Arduino Board
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b. Compile and download the following working code to the Arduino Boardusing Arduino IDE
#include <LiquidCrystal.h>
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
int runTimer = 1; // true condition for timer
int serialData = 0; // false condition for serial communication
int speakerPin = 8;
int data = 0; // default condition
void setup() {
pinMode(speakerPin, OUTPUT);
// set up the LCD's number of rows and columns:
lcd.begin(16, 2);
}
void loop() {
// To execute timer only once
if(runTimer == 1){
// Print a message to the LCD.
lcd.clear();
lcd.print("Timer: ");
//Start timer
timer();
}
runTimer = 0;
lcd.noDisplay();
delay(250);
// Sound Buzzer
for(int duration = 0; duration < 100; duration ++){
digitalWrite(speakerPin, HIGH);
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delayMicroseconds(2000);
digitalWrite(speakerPin, LOW);
delayMicroseconds(2000);
}
lcd.display();
delay(250);
}
void timer(){
// For loop to run the COUNT-DOWN in Seconds
for(int timer = 10; timer > 0; --timer){
// Set the Curosr to the space after the display "TIMER: "
if(timer >= 10)
lcd.setCursor(6,0);
else{
lcd.setCursor(6,0);
lcd.print("0");
lcd.setCursor(7,0);
}
// Display the COUNT-DOWN Seconds
lcd.print(timer);
lcd.print("s");
delay(1000);
}
// Bring the Cursor to the initial position
lcd.setCursor(0,0);
lcd.clear();
lcd.print("Buzzer!");
}
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c. Timer Display
In order to display the timer you will have to wire the 16x2 LCD display (Figure 3) to 6 Digital
Output pins of the Arduino board.
Wire the pins according to the following assignments:
LCD
1
2
3
4
5
6
7 8 9 10 11 12 13 14 15
Arduino
GND +5V GND 12 GND 11 Board
-
-
-
5
4
3
2
16
+5V GND
Figure 3: 16x2 Liquid Crystal Display
d. Self-Timer and Sound Buzzer
Press the RESET Button of the Arduino board, the timer will countdown from 10 seconds, as
programmed. Once the timer countdown reaches 0s, the buzzer will go on and the LCD display
will blink “Buzzer!”
The program is reset every time you press the RESET Button of the Arduino board and the timer
countdown begins again.
e. Questions
i.
ii.
How will you make the timer countdown from 100 seconds?
How will you make the Buzzer buzz only for a fixed amount of time after the timer
countdown reaches 0s?
Answer the above questions to your TA and demo your circuit.
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Figure 4: Timer Countdown Display of Selftimer using Arduino Board
Figure 5: Buzzer Display of Selftimer using Arduino Board
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f. Play Melody
Use the sound buzzer (32S4120) to produce musical notes. Refer to the following links
Musical Note Frequencies from TechLib.com
http://www.techlib.com/reference/musical_note_frequencies.htm
Note: there are 5 columns in the matrix – these refer to difference octaves. For the purposes of
this assignment, choose your favorite octave (preferably one near the middle) and go with it.
(ignore sharps (#) and just go with plain A B C, etc)
Music Theory & Note Reading from ThinkQuest.org
http://library.thinkquest.org/15413/theory/note-reading.htm
Note: we will assume a whole note is 1 second long
Program the Arduino board using the code available from the following link:
http://www.arduino.cc/en/Tutorial/Melody
Note: Arduino is open source. The Arduino website provides links to various other interesting
projects.
g. Extra Credit
i.
Program the Arduino to play three different musical notes. Each musical note gets 5
points.
ii.
Program the Arduino to count down from 20s and play a musical note of your choice for
two cycles. (5 points)
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