Data Sheet

37 : circuit 2a
NEW COMPONENTS
BUZZER: The buzzer uses a small
magnetic coil to vibrate a metal disc inside
a plastic housing. By pulsing electricity
through the coil at different rates, different
frequencies (pitches) of sound can be
produced. Attaching a potentiometer to
the output allows you to limit
the amount of current moving
through the buzzer and lower
its volume.
NEW CONCEPTS
RESET BUTTON: The RedBoard has a
built-in reset button. This button will reset
the board and start the code over from the
beginning, running setup()then loop().
TONE FUNCTION: To control the
buzzer, you will use the tone() function.
This function is similar to PWM in that
it generates a wave that is of a certain
frequency on the specified pin. The
frequency and duration can both be passed
to the tone() function when calling it.
To turn the tone off, you need to call
noTone() or pass a duration of time for it
to play and then stop. Unlike PWM, tone()
can be used on any digital pin.
ARRAYS are used like variables, but they
can store multiple values. The simplest
array is just a list. Imagine that you want
to store the frequency for each note of
the C major scale. We could make seven
variables and assign a frequency to
each one, or we could use an array and
store all seven in the same list. To refer
to a specific value in the array, an index
number is used. Arrays are indexed from
0. For example, to call the first element in
the array, use array_name[0]; to call the
second element, use array_name[1]; and
so on.
MUSICAL
NOTE
FREQUENCY
(HZ)
USING
VARIABLES
USING AN
ARRAY
A 220 A_FREQUENCY FREQUENCY[0]
B 247 B_FREQUENCY FREQUENCY[1]
C 261 C_FREQUENCY FREQUENCY[2]
D 294 D_FREQUENCY FREQUENCY[3]
E 330 E_FREQUENCY FREQUENCY[4]
F 349 F_FREQUENCY FREQUENCY[5]
G 392 G_FREQUENCY FREQUENCY[6]
Circuit 2A: Buzzer
In this circuit, you’ll use the RedBoard and
a small buzzer to make music, and you’ll
learn how to program your own songs
using arrays.
YOU
NEED
IOREF RESET
RESET
7-15V
SCL
SDA
AREF
GND
13 12
~11 ~10
~9
8
7
~6 ~5
4
~3
2 1 0
TX
RX
13
3.3V 5V GND GND VIN
A0 A1 A2 A3 A4 A5
POWER ANALOG IN
DIGITAL (PWM~)
ON
ISP
TX
RX
START SOMETHING
IOREF RESET
RESET
7-15V
SCL
SDA
AREF
GND
13 12
~11 ~10
~9
8
7
~6 ~5
4
~3
2 1 0
TX
RX
13
3.3V 5V GND GND VIN
A0 A1 A2 A3 A4 A5
POWER ANALOG IN
DIGITAL (PWM~)
ON
ISP
TX
RX
START SOMETHING
POTENTIOMETER PIEZO BUZZER 4 JUMPER WIRES