def cmd_tracker(self, args):
        '''tracker command parser'''
        usage = "usage: tracker <start|set|arm|disarm|level|param|mode|position> [options]"
        if len(args) == 0:
            print(usage)
            return
        if args[0] == "start":
            self.cmd_tracker_start()
        elif args[0] == "set":
            self.tracker_settings.command(args[1:])
        elif args[0] == 'arm':
            self.cmd_tracker_arm()
        elif args[0] == 'disarm':
            self.cmd_tracker_disarm()
        elif args[0] == 'level':
            self.cmd_tracker_level()
        elif args[0] == 'param':
            self.cmd_tracker_param(args[1:])
        elif args[0] == 'mode':
            self.cmd_tracker_mode(args[1:])
        elif args[0] == 'position':
            self.cmd_tracker_position(args[1:])
        elif args[0] == 'calpress':
            self.cmd_tracker_calpress(args[1:])
        else:
            print(usage)
tracker command parser