Store variable data and display sum after 60 seconds

[the_dude]

Hi @deanhystad, I was able to tweak some code and get the below to work, in a manual button press environment that is. It runs for 10 seconds and reads the serial data sent within each second, adds it to a list, and then adds it all up when 10 seconds has passed.

Once I uploaded it to the machine it's monitoring, in my case a laser engraving machine, I quickly discovered the laser fires so rapidly that the serial can send multiple messages (or sets of data) within that second which ultimately tells me this script won't work, like you said.

I would rather have the serial data be the trigger to save it to a list and at the end of 10 seconds add them all up. Can you help me with that? I know it comes across as asking for you to write it for me but I just need some help. Thanks in advance!

0.02799999950.04899999610.03500000000.0250000000
0.0000000000
0.0000000000
0.0000000000
0.90399999610.02700000040.05000000000.03400000330.0250000000
0.0000000000
starting to calculate...
['0.02799999950.04899999610.03500000000.0250000000', '0.0000000000', '0.0000000000', '0.0000000000', '0.90399999610.02700000040.05000000000.03400000330.0250000000', '0.0000000000']
[color=#E74C3C]Traceback (most recent call last):
  File "****.py", line 28, in <module>
    mynums_floated = [float(v) for v in mynums]
  File "****.py", line 28, in <listcomp>
    mynums_floated = [float(v) for v in mynums]
ValueError: could not convert string to float: '0.02799999950.04899999610.03500000000.0250000000'[/color]
>>> 

Working code (sort of):

import serial
import os
import time

#mynums = []

if __name__ == '__main__':
    ser = serial.Serial('/dev/ttyUSB0', 9600, timeout=1)
    ser.flush()
    
    while True:
        if ser.in_waiting > 0:
            mynums = []
            t_end = time.time() + 10
            while time.time() < t_end:
                value = ser.readline().decode('utf-8').rstrip() 
                runTime = (value) 
                runTime2 = ("0.0000000000")

                if runTime == "":
                    mynums.append(runTime2)
                    print(runTime2)
                if runTime != "":
                    mynums.append(runTime)
                    print(runTime)
            print("starting to calculate...")
            print(mynums)
            mynums_floated = [float(v) for v in mynums]
            print(sum(mynums_floated))
            print("Calculation Done!")

This code doesn't make any sense.

import serial
import os
import time
 
mynums = []
 
if __name__ == '__main__':
    ser = serial.Serial('/dev/ttyUSB0', 9600, timeout=1)
    ser.flush()
 
    while True:
        if ser.in_waiting > 0:
            t_end = time.time() + 10
            while time.time() < t_end:
                value = ser.readline().decode('utf-8').rstrip() #reading from serial. It's a float 0.00 (second.milliseconds)
                runTime = (value) #convert variable to float.
                print(value) #prints variable result.
                mynums.append(runTime)
            print(sum(mynums))

Translating to Not Python

Repeat this
    If there is something in my serial port wait 10 seconds before I eventually read it and append to a list.

Nobody has the code quite right yet. You should not be using ser.in_waiting() with ser.readline(). You can have bytes in the buffer but still be waiting for the newline character. Instead of peeking in the buffer just do the readline() with a timeout and check the length of the returned value.

import serial
import time
  
ser = serial.Serial('/dev/ttyUSB0', 115200, timeout=1)
ser.flush()

end_time = time.time() + 60
total = 0
while time.time() < end_time:
    value = ser.readline()
    if len(value) > 0:  # len() will be zero if readline() timed out
        print(value)
        total += float(value.decode())

print("Total", total)

[deanhystad]

This is not a speed thing. Your laser engraving machine is not sending individual values separated by newlines. It appears to send 4 values at a time, and it doesn't look like there are any delimiters between the values. That is rather rude.

I would start by reading 1 value and seeing what is sent. Always start solving a problem by understanding what the problem really is. Does the engraver send 4 numbers at a time or is there something happening in the program that concatenates the strings (I don't see how).

import serial
 
ser = serial.Serial('/dev/ttyUSB0', 9600, timeout=1)
ser.flush()

while True:
    value = ser.readline()
    if len(value) > 0:
        print('Bytes', value)
        print('String', value.decode())
        break

Try running this and posting what is printed.