In GNURadio/GRC, how to sequentially use different audio sources as input without having to manually start and stop?

Question

I have 3-4 different audio sources in my flowchart. I want to play each source back to back (not overlayed on top of each other) without having to manually start and stop each source. Essentially, acting like a timer. For example, play source 1 then stop, wait 15 secs, play source 2, wait 30 secs, and so on.... Is there a block in the flow chart that can do this or does anyone have a python block that does this already or something similar?

Answer 1

Figured it out on my own kind of...basically I made my own embedded python block that delays the inputs I want by so many seconds. Here is what I came up with:

import time 
import numpy as np
from gnuradio import gr


class blk(gr.sync_block):  
    """Embedded Python Block that time delays the input file"""

    # initializes the GRC Block input, output, block title, and parameters
    def __init__(self, delay = 0):  
        gr.sync_block.__init__(
            self,
            name='Time Delayed Input',
            in_sig=[np.float32],
            out_sig=[np.float32]
        )
 
        # sets a callback for time delay in seconds specified in the GRC block
        self.delay = time.sleep(delay)

    def work(self,  input_items,  output_items):
        
        # sets output equal to the input to just pass through the block 
        output_items[0][:] = input_items[0]
        
        # calls a time delay in seconds 
        sleep.delay

        # returns the input as the output after the specified delay 
        return len(output_items[0])