Using the scenario from the previous section, we can build a simple program to display a random character on an 8 x 8 LED dot matrix module. We can use random.choice(string.ascii_letters) to retrieve a random character in Python. After this, the random value is passed to the MAX7219 library.
Let's start. Create a file named ch04_03.py. The following is completed code for our scenario:
# ch04_03.py file
import max7219.led as led
import time
import random
import string
device = led.matrix(cascaded=1)
print("Running...")
print("Press CTRL+C to exit ")
try:
while 1:
character = random.choice(string.ascii_letters)
print "display ", character
device.letter(0, ord(character))
time.sleep(1)
except KeyboardInterrupt:
device.command(led.constants.MAX7219_REG_SHUTDOWN,0x00)
time.sleep(0.01)
print("done")Save this code. Execute this program by typing the following command:
sudo python ch04_03.py...