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1.1.3 LED Bar Graph¶
Introduction¶
In this project, we sequentially illuminate the lights on the LED Bar Graph.
Required Components¶
In this project, we need the following components.
It’s definitely convenient to buy a whole kit, here’s the link:
Name |
ITEMS IN THIS KIT |
LINK |
---|---|---|
Raphael Kit |
337 |
You can also buy them separately from the links below.
COMPONENT INTRODUCTION |
PURCHASE LINK |
---|---|
- |
Schematic Diagram¶
T-Board Name |
physical |
wiringPi |
BCM |
GPIO18 |
Pin 12 |
1 |
18 |
GPIO23 |
Pin 16 |
4 |
23 |
GPIO24 |
Pin 18 |
5 |
24 |
GPIO25 |
Pin 22 |
6 |
25 |
SPICE0 |
Pin 24 |
10 |
8 |
SPICE1 |
Pin 26 |
11 |
7 |
GPIO12 |
Pin 32 |
26 |
12 |
GPIO16 |
Pin 36 |
27 |
16 |
GPIO20 |
Pin 38 |
28 |
22 |
GPIO21 |
Pin 40 |
29 |
21 |
Experimental Procedures¶
Step 1: Build the circuit.
Note
Pay attention to the direction when connecting. If you connect it backwards, it will not light up.
Step 2: Go to the folder of the code.
cd ~/raphael-kit/python-pi5
Step 3: Run the executable file.
sudo python3 1.1.3_LedBarGraph_zero.py
After the code runs, you will see the LEDs on the LED bar turn on and off regularly.
Code
Note
You can Modify/Reset/Copy/Run/Stop the code below. But before that, you need to go to source code path like raphael-kit/python-pi5
. After modifying the code, you can run it directly to see the effect.
#!/usr/bin/env python3
from gpiozero import LED
from time import sleep
# Define GPIO pins where LEDs are connected
led_pins = [18, 23, 24, 25, 8, 7, 12, 16, 20, 21]
# Create LED objects for each pin
leds = [LED(pin) for pin in led_pins]
def odd_led_bar_graph():
# Sequentially light up odd-numbered LEDs (index 0, 2, 4, etc.)
for i in range(5):
j = i * 2 # Calculate odd index
leds[j].on() # Turn on odd-numbered LED
sleep(0.3) # Delay for visual effect
leds[j].off() # Turn off LED
def even_led_bar_graph():
# Sequentially light up even-numbered LEDs (index 1, 3, 5, etc.)
for i in range(5):
j = i * 2 + 1 # Calculate even index
leds[j].on() # Turn on even-numbered LED
sleep(0.3) # Delay for visual effect
leds[j].off() # Turn off LED
def all_led_bar_graph():
# Sequentially light up all LEDs one by one
for led in leds:
led.on() # Turn on LED
sleep(0.3) # Delay for visual effect
led.off() # Turn off LED
def turn_off_all_leds():
# Turn off all LEDs at once
for led in leds:
led.off()
try:
# Main loop to cycle through LED patterns
while True:
odd_led_bar_graph() # Activate odd-numbered LEDs
sleep(0.3) # Pause between patterns
even_led_bar_graph() # Activate even-numbered LEDs
sleep(0.3) # Pause between patterns
all_led_bar_graph() # Activate all LEDs
sleep(0.3) # Pause before restarting
except KeyboardInterrupt:
# Handle interruption (Ctrl+C) gracefully
turn_off_all_leds() # Ensure all LEDs are turned off on exit
pass
Code Explanation
These lines import the necessary classes and functions.
LED
fromgpiozero
for LED control andsleep
fromtime
for delays.#!/usr/bin/env python3 from gpiozero import LED from time import sleep
The
led_pins
list contains the GPIO pin numbers.leds
is a list ofLED
objects, each corresponding to a pin inled_pins
.# Define GPIO pins where LEDs are connected led_pins = [18, 23, 24, 25, 8, 7, 12, 16, 20, 21] # Create LED objects for each pin leds = [LED(pin) for pin in led_pins]
Let the LED on the odd digit of the LED Bar Graph light on in turn.
def odd_led_bar_graph(): # Sequentially light up odd-numbered LEDs (index 0, 2, 4, etc.) for i in range(5): j = i * 2 # Calculate odd index leds[j].on() # Turn on odd-numbered LED sleep(0.3) # Delay for visual effect leds[j].off() # Turn off LED
Make the LED on the even digit of the LED Bar Graph light on in turn.
def even_led_bar_graph(): # Sequentially light up even-numbered LEDs (index 1, 3, 5, etc.) for i in range(5): j = i * 2 + 1 # Calculate even index leds[j].on() # Turn on even-numbered LED sleep(0.3) # Delay for visual effect leds[j].off() # Turn off LED
Let the LED on the LED Bar Graph light on one by one.
def all_led_bar_graph(): # Sequentially light up all LEDs one by one for led in leds: led.on() # Turn on LED sleep(0.3) # Delay for visual effect led.off() # Turn off LED
The
while True
loop continuously cycles through the LED patterns. Theexcept
block handles a KeyboardInterrupt (Ctrl+C), ensuring all LEDs are turned off on exit.
try: # Main loop to cycle through LED patterns while True: odd_led_bar_graph() # Activate odd-numbered LEDs sleep(0.3) # Pause between patterns even_led_bar_graph() # Activate even-numbered LEDs sleep(0.3) # Pause between patterns all_led_bar_graph() # Activate all LEDs sleep(0.3) # Pause before restarting except KeyboardInterrupt: # Handle interruption (Ctrl+C) gracefully turn_off_all_leds() # Ensure all LEDs are turned off on exit pass