28123 Parallax Inc, 28123 Datasheet - Page 228

• Manufacturer Part Number: 28123
• Description: TEXT WHAT'S A MICROCONTROLLER
• Manufacturer: Parallax Inc
• Type: Programmingr

Specifications of 28123

• Style: Book
• Title: What's a Microcontroller?
• Contents: Whats a Microcontroller? Text
• Product: Microcontroller Accessories
• Core Processor: PIC16C57c
• Flash: 128 Bytes
• Operating Supply Voltage: 9 V
• Board Size: 31 mm x 16 mm
• Lead Free Status / RoHS Status: Not applicable / Not applicable

ACTIVITY #1: BUILDING AND TESTING THE SPEAKER
In this activity, you will build and test the piezoelectric speaker circuit.
Speaker Parts
(1) Piezoelectric speaker
(2) Jumper wires
Building the Piezoelectric Speaker Circuit
The negative terminal of the piezoelectric speaker should be connected to Vss, and the
positive terminal should be connected to an I/O pin. The BASIC Stamp will then be
programmed to send high/low signals to the piezoelectric speaker’s positive terminal.
How the Piezoelectric Speaker Circuit Works
When a guitar string vibrates, it causes changes in air pressure. These changes in air
pressure are what your ear detects as a tone. The faster the changes in air pressure, the
higher the pitch, and the slower the changes in air pressure, the lower the pitch. The
element inside the piezo speaker’s plastic case is called a piezoelectric element. When
high/low signals are applied to the speaker’s positive terminal, the piezoelectric element
P9
√
Build the circuit shown in Figure 8-2.
A piezoelectric speaker is commonly referred to as a piezo speaker or piezo buzzer, and
piezo is pronounced “pE-A-zO”.
Vss
P15
P14
P13
P12
P11
P10
P9
P8
P7
P6
P5
P4
P3
P2
P1
P0
X2
X3
Vdd
+
Vin
Vss
Figure 8-2
Piezoelectric
Speaker Circuit
Schematic and
Wiring Diagram