Another idea. It would be great if you could set your goal, and then if you went above your goal, it would move the goal line on the bar. Say you have a bar that is 100 pixels wide and your goal is 100. When you hit 100, the bar it completely filled. When you hit 200, the bar is completely filled, but the goal line has moved to 50 (50%). If your sensor hits 300, the bar moves to 33 (33%) etc.
Another idea. It would be great if you could set your goal, and then if you went above your goal, it would move the goal line on the bar. Say you have a bar that is 100 pixels wide and your goal is 100. When you hit 100, the bar it completely filled. When you hit 200, the bar is completely filled, but the goal line has moved to 50 (50%). If your sensor hits 300, the bar moves to 33 (33%) etc.