Develop Reference

Resetting the count of variable in a while loop

from microbit import *
from ssd1306 import initialize, clear_oled
from ssd1306_stamp import draw_stamp
from ssd1306_img import create_stamp
from ssd1306_text import add_text
import utime as time
window = []
threshold = 550 # limit
count = 0
sample = 0
beat = False
start = False
good = create_stamp(Image.HAPPY)
bad = create_stamp(Image.SAD)
heart = create_stamp(Image.HEART)
values = []
def mean(datalist):
sum = 0
for i in datalist:
sum += i
if len(datalist) > 0:
return sum/len(datalist)
else:
return None
while True:
if button_a.was_pressed():
while True:
signal = pin1.read_analog()
window.append(signal)
avg = round(mean(window))
values.append(avg)
if len(window) == 11:
window.pop(0)
if beat is False and avg >= threshold+10:
beat = True
count += 1
display.show(Image.HEART, wait=False)
if count == 1:
t1 = time.ticks_ms()
if count == 11:
t2 = time.ticks_ms()
T = t2 - t1
bpm = round(600*1000/(T))
display.scroll(str(bpm))
initialize()
clear_oled()
add_text(0, 0, "Heart rate :")
add_text(0, 3, str(bpm) + " bpm")
if 60 <= bpm <= 100:
draw_stamp(38, 24, good, 1)
else :
draw_stamp(38, 24, bad, 1)
count = 0
sleep(2000)
if button_b.was_pressed():
break
count = 0
elif beat is True and avg <= threshold-10:
beat = False
display.clear()
sample += 1
if sample == 250:
threshold = mean(values)
values = []
sample = 0
sleep(20)
sleep(20)
This is the code connect to the microbit, and the function is about the heart rate sensor, which it will appear the average beat per minute when sensing 10 beats of the heart.
I am thinking of adding a function that if button b is pressed, the loop will pause, and press the button a to start again. I tried to add a break function in the loop, it worked when I click the button b, it pause the loop, however, the count of beat won't reset, and the time between the beat is also recorded although I break the loop.
Is there any way that I can break the loop and reset the count?

You should reset the counter before breaking. In your current code the line for the count is not executing since it breaks out before it reaches it.
if button_b.was_pressed():
count = 0
break

Check a condition every 3 minutes without functions and without interrupting the loop

I have this working code that checks a conditions every 3 minutes considering the local time, so every 0, 3, 6, 9.....It prints "checking condition".
import time
def get_next_time():
minute = time.localtime().tm_min
result = 3 - (minute % 3) + minute
if result == 60:
result = 0
return result
next_run = get_next_time()
while True:
now = time.localtime()
if next_run == now.tm_min:
print("checking condition")
#some condition
next_run = get_next_time()
time.sleep(1)
The problem is that I need the code without functions, so I need to find a way to write this code without using any funcion, and I cannot use break or interrput the loop
I tried:
while True:
minute = time.localtime().tm_min
result = 3 - (minute % 3) + minute
if result == 60:
result = 0
now = time.localtime()
if result == now.tm_min:
print("checking conditions")
time.sleep(1)
But it does not work: it does not do nothing.
Any ideas?

you can compact the function in one statement:
import time
next_run = (3 - (time.localtime().tm_min % 3) + time.localtime().tm_min)%60
while True:
now = time.localtime()
if next_run == now.tm_min:
print("checking condition")
#checking conditions...
next_run=(3 - (time.localtime().tm_min % 3) + time.localtime().tm_min)%60
time.sleep(1)

The first time, the get_next_time() will only be executed when next_run == now.tm_min. The second time, you execute it each loop
import time
minute = time.localtime().tm_min
result = 3 - (minute % 3) + minute
if result == 60:
result = 0
while True:
now = time.localtime()
if result == now.tm_min:
print("checking conditions")
minute = time.localtime().tm_min
result = 3 - (minute % 3) + minute
if result == 60:
result = 0
time.sleep(1)

Rounding to the next multiple of 3 minutes contradicts the specification "every 0...".
It is enough to do
import time
first= True
while True:
minute= time.localtime().tm_min
if first or minute == target:
print("checking condition")
first= False
target= (minute + 3) % 60
time.sleep(1)
Update:
I modified the code so that a single call to localtime is made on every iteration, to make fully sure that the minutes do not change between the calls.
More compact but less efficient:
import time
while True:
minute= time.localtime().tm_min
if 'target' not in locals() or minute == target:
print("checking condition")
target= (minute + 3) % 60
time.sleep(1)

Ultrasonic sensor as counter

I am trying to code ultrasonic sensors to count the number of cars in a parking lot. I am relatively new to Python, so I am asking here for help.
I have three parking slots, in which each of them has an ultrasonic sensor.
How do I make it so that the sensors and their counters work together? For example, when the parking slots are empty, the counter shows three parking slots available. When two parking slots are filled, the counter shows one availability, etc.
I have done the following code, and I am wondering how I could continue to achieve my objective?
# Sensor 1
def distance_1():
time.sleep(0.5)
GPIO.output(TRIG_1, True)
time.sleep(0.00001)
GPIO.output(TRIG_1, False)
print("Reading Sensor 1")
while GPIO.input(ECHO_1) == 0:
start = time.time()
while GPIO.input(ECHO_1) == 1:
end = time.time()
duration = end - start
sound = 34000 / 2
distance = duration * sound
round(distance, 0)
total = 3
count = total
if distance <= 10:
count -= 1
elif distance > 10:
count += 1
if count < 0:
count = 0
elif count > total:
count = total
print(count)
mylcd.lcd_display_string("{}".format(count), 2)
# Sensor 2
def distance_2():
time.sleep(0.5)
GPIO.output(TRIG_2, True)
time.sleep(0.00001)
GPIO.output(TRIG_2, False)
print("Reading Sensor 2")
while GPIO.input(ECHO_2) == 0:
start = time.time()
while GPIO.input(ECHO_2) == 1:
end = time.time()
duration = end - start
sound = 34000 / 2
distance = duration * sound
round(distance, 0)
total = 3
count = total
if distance <= 10:
count -= 1
elif distance > 10:
count += 1
if count < 0:
count = 0
elif count > total:
count = total
print(count)
mylcd.lcd_display_string("{}".format(count), 2)
# Sensor 3
def distance_3():
time.sleep(0.5)
GPIO.output(TRIG_3, True)
time.sleep(0.00001)
GPIO.output(TRIG_3, False)
print("Reading Sensor 3")
while GPIO.input(ECHO_3) == 0:
start = time.time()
while GPIO.input(ECHO_3) == 1:
end = time.time()
duration = end - start
sound = 34000 / 2
distance = duration * sound
round(distance, 0)
total = 3
count = total
if distance <= 10:
count -= 1
elif distance > 10:
count += 1
if count < 0:
count = 0
elif count > total:
count = total
print(count)
mylcd.lcd_display_string("{}".format(count), 2)
while True:
distance_1()
distance_2()
distance_3()
GPIO.cleanup()

The trouble with programming is there are so many ways to achieve the same result.
Looking at your code, I would suggest taking a step back and refactoring it to use Python classes instead. You have a lot of code repetition happening, and eventually, the code will break if you need to keep adding more sensors.
For example:
class Parking:
"This is a parking class"
def __init__(self, space):
self.space = space
def empty(self):
if self.space == 0:
print('Parking space is empty')
def full(self):
if self.space == 1:
print('Parking space is full')
def distance(self):
time.sleep(0.5)
GPIO.output(TRIG, True)
. . .
# Input:
sensor1 = Parking(1)
sensor2 = Parking(1)
sensor3 = Parking(0)
# Output:
sensor1.empty()
sensor2.empty()
sensor3.empty()
# Output:
sensor1.full()
sensor2.full()
sensor3.full()
You can then update a dictionary with the output to monitor the latest sensor information. Ideally, the dictionary would be written to a central file accessible by all the sensors or raspberry pis to read.
available_spaces = {"sensor1": 0, "sensor2": 1, "sensor3": 0}

I analyzed your code and I did some refactorings.
I suggest you to use constant values initialization (the config section you see in the code below). The values I used are random.
A function can be parametrized, so you can pass arguments to functions, and avoid writing the same piece of code changing only a few values in the same place.
You should set up your microcontroller when the script starts, to tell the board how you are using the pins (as input or output).
I didn't dig into on the snippet above the lcd_display_string and why are you doing those operations. I suppose that these are required to print on screen the distance.
## configuration
# trigger
TRIG_1 = 17
TRIG_2 = 27
TRIG_3 = 22
# echo
ECHO_1 = 10
ECHO_2 = 9
ECHO_3 = 11
# timings
INITIAL_DELAY = 0.5
TRIGGERING_DELAY = 0.00001
## support functions
# initializing GPIO
def set_up():
# set trigger GPIOs as output pins
GPIO.setup(TRIG_1, GPIO.OUT)
GPIO.setup(TRIG_2, GPIO.OUT)
GPIO.setup(TRIG_3, GPIO.OUT)
# set echo GPIOs as input pins
GPIO.setup(ECHO_1, GPIO.IN)
GPIO.setup(ECHO_2, GPIO.IN)
GPIO.setup(ECHO_3, GPIO.IN)
# I didn't dig into these values and why are you doing these operations. I suppose that these are required to print on screen the distance.
def print_distance_on_lcd(distance):
total = 3
count = total
if distance <= 10:
count -= 1
elif distance > 10:
count += 1
if count < 0:
count = 0
elif count > total:
count = total
print(count)
mylcd.lcd_display_string("{}".format(count), 2)
def trigger(trigger):
time.sleep(INITIAL_DELAY)
GPIO.output(trigger, True) # set output pin on HIGH state
time.sleep(TRIGGERING_DELAY)
GPIO.output(trigger, False) # set output pin on LOW state
def distance(t, echo):
trigger(t)
# initializing the variables here, allows you to use it outside the while block below
# using variable names that explains their content
start_time = time.time()
end_time = time.time()
# this block is not wrong, but unnecessary: initializing the variable like above is enough
'''
while GPIO.input(echo) == 0:
start_time = time.time()
'''
while GPIO.input(echo) == 1:
end_time = time.time()
duration = end_time - start_time
sound = 34000 / 2
distance = duration * sound
return distance
# call initialization function (this will be executed only one time)
set_up()
# loop forever
while True:
set_up()
print("Reading Sensor 1")
distance_sensor_1 = distance(TRIG_1, ECHO_1)
print_distance_on_lcd(distance_sensor_1)
print("Reading Sensor 2")
distance_sensor_2 = distance(TRIG_2, ECHO_2)
print_distance_on_lcd(distance_sensor_2)
print("Reading Sensor 3")
distance_sensor_3 = distance(TRIG_3, ECHO_3)
print_distance_on_lcd(distance_sensor_3)
GPIO.cleanup()

trying to get an if statement to be triggered during certain times of day

im fairly new with python but im tring to get a device to turn on for one minute and off for 3 minutes repeatedly from the times of 9am to 5pm and i can't get the if statement to reference the updated time from the loop any help would be greatly appreciated!!!
import datetime
import time
n = "on" #to be replaced with GPIO output
f = "off" #to be replaced with GPIO output
nt = "tis not be the time" #used to see if working or not
tt = "tis be time" #used to see if working or not
now = datetime.datetime.now()
hour = now.hour
def count():
now = datetime.datetime.now()
hour = now.second
total = 1
if hour >= 8 and hour <= 16:
now = datetime.datetime.now()
hour = now.hour
for i in range(1,100):
total = total*2
print (tt)
print (n)
time.sleep(60)
print(f)
time.sleep(180)
now = datetime.datetime.now()
hour = now.second
print (hour)
else :
for i in range(1,100):
now = datetime.datetime.now()
hour = now.hour
print (nt)
print (hour)
time.sleep(10)
count()

You could fix it with a while loop instead, it would look like this, just put all of it inside your function
now = datetime.datetime.now()
hour = now.hour
if hour >= 8 and hour <= 16:
run = True
else:
run = False
while run:
total = total*2
print (tt)
print (n)
time.sleep(60)
print(f)
time.sleep(180)
now = datetime.datetime.now()
hour = now.second
print (hour)
if hour >= 8 and hour <= 16:
run = True
else:
run = False
while run == False:
now = datetime.datetime.now()
hour = now.hour
print (nt)
print (hour)
time.sleep(10)
if hour >= 8 and hour <= 16:
run = True
else:
run = False

Maybe using a while statement. In addition, you have hour = now.second on the second line of the function count and I think it should be hour = now.hour.
See the code with comments:
import datetime
import time
n = "on" #to be replaced with GPIO output
f = "off" #to be replaced with GPIO output
nt = "tis not be the time" #used to see if working or not
tt = "tis be time" #used to see if working or not
#Next lines are redundant, commented out.
#now = datetime.datetime.now()
#hour = now.hour
def count():
now = datetime.datetime.now()
hour = now.hour #now.second
total = 1
while hour >= 8 and hour <= 16:
now = datetime.datetime.now()
hour = now.hour
# for i in range(1,100): -> why you need this?
total = total*2
print (tt)
print (n)
time.sleep(60)
print(f)
time.sleep(180)
now = datetime.datetime.now()
hour = now.hour #now.second
print (hour)
for i in range(1,100): #I don't know why you need a loop here
now = datetime.datetime.now()
hour = now.hour
print (nt)
print (hour)
time.sleep(10)
count()
Edited for correcting another hour = now.second inside the while loop

I don't know how are you planning on running the code, but the main problem I see is that you do not have any loop for your code to run infinitely and check the time condition.
Also it's not clear for me why you need this total variable that gets doubled.
Another thing is your for loops - the condition is not clear. Why do you want to run it in this specific range?
What I would do is I would create an infinite loop and inside it make some decisions based on a clear time conditions - the conditions that are specified by you.
So if I understood your case correctly I'd rather write something like this:
# between 9am to 5pm turn on the device for 60 seconds and off for 180 seconds repeatedly
from datetime import datetime
import time
def update_device_state(state):
# TODO: implement GPIO output code
pass
def run():
device_state = 'off'
new_state = device_state
on_timer = 0
off_timer = time.time() - 180 # initial value must be over 180 seconds to trigger device on a first run
while True:
hour = datetime.now().hour
if 5 <= hour <= 17:
if device_state == 'off' and time.time() - off_timer > 180:
on_timer = time.time()
new_state = 'on'
off_timer = 0
elif device_state == 'on' and time.time() - on_timer > 60:
off_timer = time.time()
new_state = 'off'
on_timer = 0
else:
if device_state = 'on'
new_state = 'off'
on_timer = 0
off_timer = time.time()
if device_state != new_state:
update_device_state(new_state)
device_state = new_state
time.sleep(1)
run()
But the code requires some testing as I just quickly drafted it and I just briefly red it.

Countdown Clock: 01:05

How can I create a countdown clock in Python that looks like 00:00 (min & sec) which is on a line of its own. Every time it decreases by one actual second then the old timer should be replaced on its line with a new timer that is one second lower:
01:00 becomes 00:59 and it actually hits 00:00.
Here is a basic timer I started with but want to transform:
def countdown(t):
import time
print('This window will remain open for 3 more seconds...')
while t >= 0:
print(t, end='...')
time.sleep(1)
t -= 1
print('Goodbye! \n \n \n \n \n')
t=3
I also want to make sure that anything after Goodbye! (which would most likely be outside of the function) will be on its own line.
RESULT: 3...2...1...0...Goodbye!
I know this is similar to other countdown questions but I believe that it has its own twist.

Apart from formatting your time as minutes and seconds, you'll need to print a carriage return. Set end to \r:
import time
def countdown(t):
while t:
mins, secs = divmod(t, 60)
timeformat = '{:02d}:{:02d}'.format(mins, secs)
print(timeformat, end='\r')
time.sleep(1)
t -= 1
print('Goodbye!\n\n\n\n\n')
This ensures that the next print overwrites the last line printed:

Here is the code which counts from 01:05 to 00:00 in MM:SS format.
Python 3 :
import time
def countdown(p,q):
i=p
j=q
k=0
while True:
if(j==-1):
j=59
i -=1
if(j > 9):
print(str(k)+str(i)+":"+str(j), end="\r")
else:
print(str(k)+str(i)+":"+str(k)+str(j), end="\r")
time.sleep(1)
j -= 1
if(i==0 and j==-1):
break
if(i==0 and j==-1):
print("Goodbye!", end="\r")
time.sleep(1)
countdown(1,5) #countdown(min,sec)
Python 2 :
import time
def countdown(p,q):
i=p
j=q
k=0
while True:
if(j==-1):
j=59
i -=1
if(j > 9):
print "\r"+str(k)+str(i)+":"+str(j),
else:
print "\r"+str(k)+str(i)+":"+str(k)+str(j),
time.sleep(1)
j -= 1
if(i==0 and j==-1):
break
if(i==0 and j==-1):
print "\rGoodbye!"
time.sleep(1)
countdown(1,5) #countdown(min,sec)

For the simplicity, this code is able to say you how long it takes until the next desired time, which might be whatever you want to do in your program. In your case, this is a kind of countdown timer.
from datetime import datetime
x=datetime.today()
y=x.replace(day=x.day+1, hour=3, minute=1, second=0, microsecond=0)
delta_t=y-x
secs=delta_t.seconds+1
second = (secs % 60)
minut = (secs / 60) % 60
hour = (secs / 3600)
print ("Seconds: %s " % (second))
print ("Minute: %s " % (minut))
print ("Hour: %s" % (hour))
print ("Time is %s:%s:%s" % (hour, minut, second))
Then, output is as follows:
Seconds: 50
Minute: 32
Hour: 12
Time is 12:32:50
Good luck with your coding.

Maybe this link will help:
Making a Timer in Python 3
And look at my answer, it is same for your too!
Anyway, here is answer:
import time
import os
hour = int(input('Enter any amount of hours you want -+==> '))
minute = int(input('Enter any amount of minutes you want -+==> '))
second = int(input('Enter any amount of seconds you want -+==> '))
time = hour*10800 + minute*3600 + second*60
print('{}:{}:{}'.format(hour,minute,second))
while time > 0:
time = time - 1
seconds = (time // 60) % 60
minutes = (time // 3600)
hours = (time // 10800)
print('Time Left -+==> ',hours,':',minutes,':',seconds,)
os.system("CLS")
if time == 0:
print('Time Is Over!')
Input:
Enter any amount of hours you want -+==> 0
Enter any amount of minutes you want -+==> 0
Enter any amount of seconds you want -+==> 10
Output # All are on the same line
Time Left -+==> 0:0:10
Time Left -+==> 0:0:9
Time Left -+==> 0:0:8
Time Left -+==> 0:0:7
Time Left -+==> 0:0:6
Time Left -+==> 0:0:5
Time Left -+==> 0:0:4
Time Left -+==> 0:0:3
Time Left -+==> 0:0:2
Time Left -+==> 0:0:1
Time Left -+==> 0:0:0
Time Is Over!

import time
import sys
print(' ')
print('Countdown Timer, By Adam Gay')
print(' ')
print('Instructions: Input time to countdown from.')
print(' ')
c=':'
hourz=input('Hours: ')
minz=input('Minutes: ')
secz=input('Seconds: ')
print(' ')
hour=int(hourz)
min=int(minz)
sec=int(secz)
while hour > -1:
while min > -1:
while sec > 0:
sec=sec-1
time.sleep(1)
sec1 = ('%02.f' % sec) # format
min1 = ('%02.f' % min)
hour1 = ('%02.f' % hour)
sys.stdout.write('\r' + str(hour1) + c + str(min1) + c + str(sec1))
min=min-1
sec=60
hour=hour-1
min=59
Print('Countdown Complete.')
time.sleep(30)