Water Level Monitor Using Raspberry Pi and OLED display

import time

import Adafruit_GPIO.SPI as SPI
import Adafruit_SSD1306

from PIL import Image
from PIL import ImageDraw
from PIL import ImageFont
import RPi.GPIO as GPIO
import time



# Raspberry Pi pin configuration:
RST = 24
# Note the following are only used with SPI:
DC = 23
SPI_PORT = 0
SPI_DEVICE = 0

TRIG = 14
ECHO = 15
i=0

dist_from_base =  10 #Write the distance from the sensor to the base of the bucket
GPIO.setmode(GPIO.BCM)
GPIO.setup(TRIG ,GPIO.OUT)
GPIO.setup(ECHO,GPIO.IN)
GPIO.setup(4 ,GPIO.OUT)

   

# 128x32 display with hardware I2C:
disp = Adafruit_SSD1306.SSD1306_128_64(rst=RST)


# Initialize library.
disp.begin()

# Clear display.
disp.clear()
disp.display()

width = disp.width
height = disp.height
image = Image.new('1', (width, height))

draw = ImageDraw.Draw(image)

draw.rectangle((0,0,width,height), outline=0, fill=0)


padding = 2
shape_width = 20
top = padding
bottom = height-padding
# Move left to right keeping track of the current x position for drawing shapes.
x = padding
# Draw an ellipse.


# Load default font.
font = ImageFont.load_default()

# Some other nice fonts to try: http://www.dafont.com/bitmap.php
#font = ImageFont.truetype('Minecraftia.ttf', 8)
GPIO.output(TRIG, False)
print("Starting.....")
time.sleep(2)

while True:
    
    GPIO.output(TRIG, True)
    time.sleep(0.00001)
    GPIO.output(TRIG, False)

    while GPIO.input(ECHO)==0:
        pulse_start = time.time()

    while GPIO.input(ECHO)==1:
        pulse_stop = time.time()

    pulse_time = pulse_stop - pulse_start


    distance = pulse_time * 17150
    distance = round(distance)
    percentage = (distance * 100)/dist_from_base
    percentage = 100 - percentage
    percentage = round(percentage, 2)
    percentage = str(percentage)
    if distance > dist_from_base:
        distance = dist_from_base
    print(round(distance, 2));
    distance = str(distance)
    draw.text((x, top),    'Distance:',  font=font, fill=255)
    draw.text((x+60, top), distance, font=font, fill=255)
    draw.text((x+75, top), 'cm', font=font, fill=255)
    draw.text((x, top+ 20), 'percentage of bucket filled:', font=font, fill=255)
    draw.text((x, top+ 30), percentage, font=font, fill=255)
    draw.text((x+30, top +30), '%', font=font, fill=255)

    # Display image.
    disp.image(image)
    disp.display()
    distance = float(distance)
    time.sleep(1)
    disp.clear()
    draw.rectangle((0,0,width,height), outline=0, fill=0)

    if distance < 4:
        draw.text((x, top + 40),    'Water will overflow',  font=font, fill=255)
        print("Water will overflow")
        GPIO.output(4, True);
        time.sleep(0.5)
        GPIO.output(4, False);
        time.sleep(0.5)
        GPIO.output(4, True);
        time.sleep(0.5)
        GPIO.output(4, False);
        time.sleep(0.5)
    else:
        GPIO.output(4, False);
        # Write two lines of text.