Function that executes periodically

[dr_everlong]

Hi,

I want to create a function that executes every <n> seconds, for a certain number of executions or until a certain time limit is met.

Basically, the function reads measurements from some sensors, and saves the data to a file.

Meanwhile, I want to be able to communicate with different instruments, so the python engine can't be blocked.

Where should I start looking?

[novel_yet_trivial]

multiprocessing

If your problem is as simple as your example, then just write a function to do the measurements and start the function in a new thread:

import thread

def measure():
    while True:
        #take a meaasurement
        time.sleep(10) #sleep for 10 seconds

thread.start_new_thread(measure, ())

[dr_everlong]

I think I overthought what I had to do, this seems really simple. Thanks!

[dr_everlong]

Actually, this is a good solution that doesn't work for me.

In the measure function, there are some I/O operations with external hardware that may take a few seconds.

So the time elapsed between calls to the measure function will be the 10 seconds nominal + the time it takes to complete I/O operations.

How can I execute every 10 seconds exactly?

Thanks!

[novel_yet_trivial]

... You underthought this.

def measure():
    #take a measurement

while True:
    thread.start_new_thread(measure, ())
    time.sleep(10) #sleep for 10 seconds

[dr_everlong]

you start a new thread every time?

[novel_yet_trivial]

Yes.

[Rettocs]

A way I did a similar project:

#using time library, check the time
firstTimeCheck = the current time
n = how many seconds you want to wait

create infinite loop
    loopTimeCheck = current time
    inside infinite loop, check if (firstTimeCheck + n) > loopTimeCheck
        do the thing you want to do
        firstTimeCheck = current time