Fipy, Creating a new file on SD card, but it is protected (no access)!

  • Hello everyone.

    I am having some trouble with Micropython, probably it's just me who is doing something wrong. What i want, is to be able to dynamically create a new .txt file on my SD card for the FiPy, and then append data to that file. I am able to create new files without any problems, but when i want to write to them, i get the following error:

    Traceback (most recent call last):
    File "", line 51, in <module>
    File "", line 38, in save_record
    OSError: [Errno 13] EACCES

    I have been using the examples shown here:

    I am trying to structure my code as a class, here is what i have so far:

    class DB():
        record_taken = None
        pending_data = False
        data_ready = False
    #Constructor initiates SD card object and mounts the card
        def __init__(self):
            sd = machine.SD()
            os.mount(sd, '/sd')
    #Method which creates a new record, name is based on the time argument
        def new_record(self, time):
            self.time = time
    #Method to append data to a record, record is again based on time argument
        def save_record(self, data, time):
            f = open('/sd/'+'record_'+str(time), 'a')
    #Method to save a records data in variable, to be used for publishing etc.
        def get_record(self, time):
            self.record_taken = open('/sd/'+'record_'+str(time), 'r')
    #Method to delete a record, again with the name being decided by the time argument
        def delete_record(self, time):
    dibs = DB()
    dibs.save_record("testdata", 22)

    line 51 is the dibs.save_record(xxx)
    line 38 is f = open('/sd/'+'record_'+str(time), 'a')

    So it would seem that the new file i am creating has somekind of protection on it, that prevents me from opening it. What am i missing?

  • @railmonitor yes. uos.remove() is the method for deleting files.

  • @robert-hh Thanks alot, i was beginning to figure it out myself. A related question is how to delete a file, can it be done without a call to uos.remove()?

    Is there something along the lines of this that will work (i tried a delete / remove but these are not known attributes)?:

    f = open('/sd/record_1.txt')

  • @railmonitor The call to open() with the 'a' mode will create the file if it does not exist yet.

  • @railmonitor said in Fipy, Creating a new file on SD card, but it is protected (no access)!:

    OSError: [Errno 13] EACCES

    Okay - i think i found the error myself just now - the uos.mkdir() method is for creating new directory, not a file, and ofc i cannot write directly in a directory.

    This naturally gives rise to another question: How do i create new files on my SD card, without manually mounting the SD card on my PC and creating the file that way?

  • @railmonitor You try to write to a directory, which you created with mkdir. If you want to a file with that name, the mkdir (or call to new_record) is not required. The call to open() with the 'a' mode will create the files if it does not exist yet.

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