Chapter 6 Buzzer
96
delay
(
1
);
}
}
If you want to close the buzzer, just set PWM frequency of the buzzer pin to 0.
void
stopAlertor
(
int
pin
){
softToneWrite
(
pin
,
0
);
}
The related functions of softTone is described as follows:
int softToneCreate (int pin) ;
This creates a software controlled tone pin.
void softToneWrite (int pin, int freq) ;
This updates the tone frequency value on the given pin.
For more details about softTone, please refer to :
http://wiringpi.com/reference/software-tone-library/
Python Code 6.2.1 Alertor
First observe the project result, and then analyze the code.
1.
Use cd command to enter 06.2.1_Alertor directory of Python code.
cd ~/Freenove_Ultimate_Starter_Kit_for_Raspberry_Pi/Code/Python_Code/06.2.1_Alertor
2.
Use the python command to execute the Python code “Alertor.py”.
python Alertor.py
After the program is executed, press the button, then the buzzer sounds. When the button is released, the
buzzer will stop sounding.
The following is the program code:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
i m port
RPi
.
GPIO
a s
GPIO
i m port
time
i m port
math
buzzerPin
=
11
# define the buzzerPin
buttonPin
=
12
# define the buttonPin
d e f
setup
( ):
g l obal
p
p r int
(
'Program is starting...'
)
GPIO
.
setmode
(
GPIO
.
BOARD
)
# Numbers GPIOs by physical location
GPIO
.
setup
(
buzzerPin
,
GPIO
.
OUT
)
# Set buzzerPin's mode is output
GPIO
.
setup
(
buttonPin
,
GPIO
.
IN
,
pull_up_down
=
GPIO
.
PUD_UP
)
# Set buttonPin's mode is
input, and pull up to high level(3.3V)
p
=
GPIO
.
PWM
(
buzzerPin
,
1
)
p
.
start
(
0
);
d e f
loop
( ):
w h ile
T r ue
:
i f
GPIO
.
input
(
buttonPin
)==
GPIO
.
LOW
:
alertor
()
p r int
(
'buzzer on ...'
)
Summary of Contents for Ultimate Starter Kit
Page 1: ...Free your innovation Freenove is an open source electronics platform www freenove com ...
Page 117: ...117 Chapter 9 Potentiometer RGBLED www freenove com support freenove com Hardware connection ...
Page 155: ...155 Chapter 14 Relay Motor www freenove com support freenove com Hardware connection OFF 3 3V ...
Page 173: ...173 Chapter 16 Stepping Motor www freenove com support freenove com Hardware connection ...
Page 239: ...239 Chapter 22 Matrix Keypad www freenove com support freenove com Circuit Schematic diagram ...
Page 240: ...Chapter 22 Matrix Keypad 240 www freenove com support freenove com Hardware connection ...
