Tham khảo tài liệu 'lego mindstorms - robotics invention system-2 projects part 15', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Robot 10 RIS Turtle Choosing a Pen Now that you are done building the Turtle you need to choose a pen to use with it. Felt tip pens or markers make the best pictures because the robot doesn t press a pencil or ballpoint pen against the paper hard enough. I used a Staedler felt tip pen designed for overhead projectors. Sharpie markers also work well but they are shorter than the Staedler so they can be held only at their end. If you want to use the Sharpie marker you need to remove the gray 2x2 plate and the yellow 2x4 plate from the penholder. The unfortunate thing about markers is they tend to bleed a lot making large dots where the robot turns. You could prevent this by lifting the pen before turning but then the lines may not connect as well. Once you have chosen a pen you need to make sure it fits properly in the penholder. When you put the pen in turn the Turtle around and check where the pen tip comes through. To make nice drawings you want the tip to be as close to the center of turning as possible. Check this by seeing if the tip is in line with the two drive axles. You can adjust the position of the pen in the holder by either adding or removing plates. If you want to be overly precise you could wrap layers of tape around the pen until it lines up exactly in the center. When you put the pen in the easiest way to set the correct height is by turning the secondary motor by hand until the penholder is in the lowest position. Then you can gently push the pen down until it touches the paper. 336 Robot 10 RIS Turtle Writing Your Program After you have downloaded the NQC program look through it to get an idea of how it works. We have indicated where to insert your commands in the main task. You can try drawing a square first Repeat 4 forward 20 right 90 Try this out and see what happens If the Turtle moves but does not stop you need to adjust the threshold for the light sensor. This is near the beginning of the program and we have explained how you should set .
