Pre-challenge – Building and programming the Ball Hunter - One or more class session In this lesson students will learn how to build and program the Ball Hunter, which is our analog for the neutrophil cell. Teachers should expect to take one class session to go over the design and program. The students, working in team, will take another one or more session to build the bot. There will also need to be a trouble-shooting session to make sure all bots are functioning properly. This will be crucial when heading into the next part. What is on this page:1) Intro to the ball hunter 2) The Castor Bot 3) The Ball Hunter 4) Programming it 5) Troubleshooting 6) Informal Assessment Note: The pictures on this page are from NXTprograms.com with permission of the creator.  1) Intro to the ball hunter In this section we create a bot that will be similar to a neutrophil (white blood cell). A neutrophil hunts down and digest bacteria. This bot will hunt down and pick up red balls and push away blue balls. This Pre-challenge is a chance to get used to working with Legos and programming it. This project is from NXTprograms.com, an excellent place to find projects (and they have the programs available for download. So you do not even have to do any programming, if you do not want to. 2) The Castor Bot You can start here. You need to build the base, the Castor Bot. "The Castor Bot is a basic two-motor drive robot with sturdy construction that turns easily. You can use it as a starting point for your own projects, and program it however you want. To get started, you could try the "NXT Program" feature of the NXT brick to select some simple movements using the buttons on the NXT brick." 3) The Ball Hunter "This robot's mission is to find the red ball and to grab onto it. You can place both the blue and red balls anywhere near the robot to start with, and the robot will try to find the red ball and grab it. It uses the ultrasonic sensor to locate the nearest ball, then it uses the light sensor to tell the red ball from the blue ball. If it finds the blue ball first, it will push it out of the way then go on to try to find the red ball." 4) Programming it Use the program Ball_Hunt for the Ball Hunter. This program makes the robot do the following: 1. Pivot in place in a full circle and find the closest ball by scanning with the ultrasonic sensor. 2. Drive to the closest ball and grab it. 3. Use the light sensor to see if the ball is blue or red. 4. If the ball is blue then push it a little farther to get it out of the way, drive back to the starting position, then go back to step 1. 5. If the ball is red then we found it, so stop. 5) Trouble-shooting Does it look it works like it suppossed to? If not check the following things: A) Light-is there enough light for the bot to see the different colored balls? B) Color-is the color of the floor consing the bot? C) Sensors-are the sensors attached to the correct ports? D) Building-was the bot built according to directions? E) Advanced-if you still having trouble then you want to look at the programming and see if it needs to be tweaked. We will talk about programming in more detail in a later section. 6) Informal Assessment A) What was most difficult about building the bot? B) What was most difficult about programming the bot? C) Did the bot behave like it is supposed to? D) Does it behave like a cell? E) How does how you built and programmed the bot compare with how a cell is created? |
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Lego Pre-Challenge: Build the Ball Hunter |