MIKROE-1189 mikroElektronika, MIKROE-1189 Datasheet - Page 35

• Manufacturer Part Number: MIKROE-1189
• Description: Development Boards & Kits - PIC / DSPIC MIKROMEDIA FOR PIC WORKSTATION v7
• Manufacturer: mikroElektronika

Specifications of MIKROE-1189

• Rohs: yes
• Product: Development Systems
• Tool Is For Evaluation Of: PIC18FJ, dsPIC33, PIC24, PIC32
• Core: dsPIC, PIC
• Operating Supply Voltage: 3.3 V

Piezo electricity is the charge which accumulates in
certain solid materials in response to mechanical pressure,
but also providing the charge to the piezo electric material
causes it to physically deform. One of the most widely
used applications of piezo electricity is the production
of sound generators, called piezo buzzers. Piezo buzzer
is an electric component that comes in different shapes
and sizes, which can be used to create sound waves
when provided with analog electrical signal. mikromedia
workStation v7 comes with piezo buzzer which can be
connected to G4.2 or G4.3 microcontroller pin. Connection
is established using SW3.8 or SW4.8 DIP switch. Buzzer is
driven by transistor Q1 (Figure 25-1). Microcontrollers can
create sound by generating a PWM (Pulse Width Modulated)
signal – a square wave signal, which is nothing more than
Piezo Buzzer
Freq = 3kHz, Duty Cycle = 50%
Freq = 3kHz, Duty Cycle = 80%
Freq = 3kHz, Duty Cycle = 20%
Figure 15-1: Piezo
buzzer connected to
G4.3 microcontroller pin
DATA BUS
PERSPECTIVE
PERSPECTIVE
PERSPECTIVE
VIEW
VIEW
VIEW
VIEW
VIEW
VIEW
TOP
TOP
TOP
G4.2
G4.3
PZ1
PZ1
PZ1
Freq = 3kHz,
Volume = 50%
Freq = 3kHz,
Volume = 80%
Freq = 3kHz,
Volume = 20%
SW3
SW4
VCC-5V
VCC-5V
VCC-5V
™
Q8
BC846
Q8
BC846
Q8
BC846
BUZZER
BUZZER
a sequence of logic zeros and ones. Frequency
of the square signal determines the pitch of the
generated sound, and duty cycle of the signal can be
used to increase or decrease the volume in the range
from 0% to 100% of the duty cycle. You can generate
PWM signal using hardware capture-compare module,
which is usually available in most microcontrollers, or by
writing a custom software which emulates the desired
signal waveform.
Supported sound frequencies
Piezo buzzer’s resonant frequency (where you can expect
it's best performance) is 3.8kHz, but you can also use it
to create sound in the range between 2kHz and 4kHz.
R27
R27
R27
10K
10K
10K
R3
1K
R3
1K
R3
1K
How to make it sing?
Buzzer starts "singing" when you provide
PWM signal from the microcontroller
to the buzzer driver. The pitch of the
sound is determined by the frequency,
and amplitude is determined by the
duty cycle of the PWM signal.
R17
10K
R16
1K
BUZZER
BUZZER
BUZZER
VCC-5V
Q1
BC846
PZ1
BUZZER
J21
J21
J21
PERSPECTIVE
VIEW
VIEW
TOP
RC2
RE1
RC2
RE1
RC2
RE1
Enabling Piezo Buzzer
In order to use the on-board Piezo Buzzer in your
application, you first have to connect the transistor
driver of piezo buzzer to the appropriate pin. This
is done using SW3.8 or SW4.8 DIP switch (never in
the same time). Once the switch is in ON position,
it connects the buzzer driver to G4.2 or G4.3 pin.
page 35