def open_sensor(
        self,
        input_source: str,
        output_dest: Optional[str] = None,
        extra_cmd: Optional[str] = None,
    ) -> Coroutine:
        """Open FFmpeg process for read autio stream.

        Return a coroutine.
        """
        command = ["-vn", "-filter:a", "silencedetect=n={}dB:d=1".format(self._peak)]

        # run ffmpeg, read output
        return self.start_worker(
            cmd=command,
            input_source=input_source,
            output=output_dest,
            extra_cmd=extra_cmd,
            pattern="silence",
        )