https://ibb.co/dhyNAU

Bin2Str - convert ascii codes 0&1 to string '0' '1'
gr embedded python block code:

import numpy as np
from gnuradio import gr

class blk(gr.sync_block):  # other base classes are basic_block, decim_block, interp_block

    def __init__(self):          
    gr.sync_block.__init__(
            self,
            name='Bin2Str',   # will show up in GRC
            in_sig=[np.uint8],
          out_sig=[np.uint8]
        )
    self.dstr = ""

    def work(self, input_items, output_items):
    self.dstr = input_items[0].tostring()
    self.dstr = self.dstr.replace('\x00', '0')
    self.dstr = self.dstr.replace('\x01', '1')
    output_items[0][:] = np.fromstring(self.dstr, dtype=np.uint8)
        return 1