private void OnTriggerEnter(Collider c)
    {
        var battery = c.gameObject.GetComponent <Battery> ();

        if (battery)
        {
            messenger.Broadcast(new BatteryCollectedMessage(battery));
        }
        else
        {
            var obstacle = c.gameObject.GetComponent <Obstacle> ();
            if (obstacle)
            {
                messenger.Broadcast(new ObstacleHitMessage(obstacle));
            }
        }
    }
    private void Update()
    {
        if (isDepleted)
        {
            return;
        }

        CurrentBatteryAmount -= decreaseSpeed * robMov.CurrentSpeed / robMov.BaseSpeed * Time.deltaTime;
        if (CurrentBatteryAmount < 0)
        {
            robMes.Broadcast(new BatteryDepletedMessage());
            isDepleted = true;
        }
    }