# Count lines. Strategy before programming. WRO Elementary 2013 ProPreview

• #222
• 31 Jul 2016
• 3:11

### English

In this video we continue with the World Robotics Olympiad 2013 and we start with a robot from the green sector and we must drop the different blocks in the different regions the green, the blue or the red. And we'll use these lines here and we'll count them and we'll know where exactly the robot is.

There are different ways and if we have our robot and on the robot we have our light sensor and we can use this light sensor to detect the lines. Then we must think of a strategy. And we have two strategies. The first one is always when we start from the green sector always to return to this line. This line at the end. And when we return here then we count. Ok, we have to drop a blue block then we count one, two lines we drop the block. Then we return again two lines forward and we have to drop a green block. One, two, three. Three lines. We drop. We return back to this line. It's a slow solution. It's not vety efficient but it's kind of stable because it always returns to the initial position. It can even align here if we have more sensors. And in this way we drop the different blocks. Let's see a footage of how the robot runs and does exactly this.

Now that we have seen the run that drops the different blocks in the sectors. In the next video we'll enter into details how we program the robot. As a task you can check the tasks below the video but one of the tasks is actually to try to count the lines and stop on the first line, stop on the second, third and the fourth. Try this and then move to the next video.

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