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Sample code to display decimal numbers on a 4-digit 7-segment display
# code modified, tweaked and tailored from code at
# http://raspi.tv/2015/how-to-drive-a-7-segment-display-directly-on-raspberry-pi-in-python
import RPi.GPIO as GPIO
import random
import time
NUMBER_OF_DIGITS = 4
def format_num(num):
digits_left = NUMBER_OF_DIGITS
format_str = ''
if num < 0:
digits_left -= 1
format_str += '-'
num *= -1
if isinstance(num, int):
len_int = len(str(num))
else:
len_int = len(str(int(round(num))))
if len_int > digits_left:
return ''
else:
if isinstance(num, int):
format_str += '%d'
else:
len_frac = digits_left - len_int
format_str += '%%.%df' % len_frac
return format_str % num
GPIO.setmode(GPIO.BCM)
# GPIO ports for the 7seg pins
segments = (11,4,23,8,7,10,18,25)
# 7seg_segment_pins (11,7,4,2,1,10,5,3) + 100R inline
for segment in segments:
GPIO.setup(segment, GPIO.OUT)
GPIO.output(segment, 0)
# GPIO ports for the digit 0-3 pins
digits = (22,27,17,24)
# 7seg_digit_pins (12,9,8,6) digits 0-3 respectively
for digit in digits:
GPIO.setup(digit, GPIO.OUT)
GPIO.output(digit, 1)
num = {
' ':(0,0,0,0,0,0,0),
'-':(0,0,0,0,0,0,1),
'0':(1,1,1,1,1,1,0),
'1':(0,1,1,0,0,0,0),
'2':(1,1,0,1,1,0,1),
'3':(1,1,1,1,0,0,1),
'4':(0,1,1,0,0,1,1),
'5':(1,0,1,1,0,1,1),
'6':(1,0,1,1,1,1,1),
'7':(1,1,1,0,0,0,0),
'8':(1,1,1,1,1,1,1),
'9':(1,1,1,1,0,1,1)
}
RAND_MAX = (10 ** NUMBER_OF_DIGITS) - 1
RAND_MIN = (-10 ** (NUMBER_OF_DIGITS - 1)) + 1
r = random.uniform(-1, 1)
max_scale = NUMBER_OF_DIGITS
if r < 0:
max_scale -= 1
n = r * (10 ** random.randint(0, max_scale))
print(n)
next_mode = 'int'
last_change = time.time()
try:
while True:
s = format_num(n).rjust(NUMBER_OF_DIGITS)
digit = 0
for char in s:
if char == '.':
continue
for loop in range(0,7):
GPIO.output(segments[loop], num[char][loop])
if digit < (NUMBER_OF_DIGITS-1) and s[digit+1] == '.':
GPIO.output(25, 1)
else:
GPIO.output(25, 0)
GPIO.output(digits[digit], 0)
time.sleep(0.001)
GPIO.output(digits[digit], 1)
digit += 1
if (time.time() - last_change) > 2:
r = random.uniform(-1, 1)
max_scale = NUMBER_OF_DIGITS
if r < 0:
max_scale -= 1
n = r * (10 ** random.randint(0, max_scale))
if next_mode == 'int':
n = int(n)
next_mode = 'float'
elif next_mode == 'float':
next_mode = 'int'
print(n)
last_change = time.time()
finally:
GPIO.cleanup()
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