Checks the connection to the attenuator, and attempts to connect if not connected.
        Will also set an appropriate ouput minimum for stimuli, if connection successful 

        :returns: bool - whether there is a connection

def attenuator_connection(self, connect=True):
        """Checks the connection to the attenuator, and attempts to connect if not connected.
        Will also set an appropriate ouput minimum for stimuli, if connection successful 

        :returns: bool - whether there is a connection
        """
        # all or none will be connected
        acquisition_modules = [self.explorer, self.protocoler, self.bs_calibrator, self.tone_calibrator, self.charter]
        if connect:
            if not acquisition_modules[0].player.attenuator_connected():
                #attempt to re-connect first
                for module in acquisition_modules:
                    success = module.player.connect_attenuator()
                if success is None:
                    StimulusModel.setMinVoltage(0.0)
                    return False
                else:
                    StimulusModel.setMinVoltage(0.005)
                    return True
            else:
                StimulusModel.setMinVoltage(0.005)
                return True
        else:
            for module in acquisition_modules:
                module.player.connect_attenuator(False)
            StimulusModel.setMinVoltage(0.0)
            return False