Chapter 14 Classic Projects

Just like Chapter 6, the purpose of this chapter is to pay a special attention to examples given in Chapter 14 and apply them to other various situations. The first example is how to design a program to explore our room. Mainly, we are using a touch sensor for this case. Letting the robot go straight for the most of time, we make lots of swing turns when the robot collides with obstacles. However, it's important to use a gear ratio 1:9 to slow the robot down for the first trial. This is because if it moves very fast, it might hurt when it collides with hard obstacles such as wall. Once the program is well designed, we can speed up by using a gear ratio 1:3. In case our room has a flight of staris going down, we can use an ultrasonic sensor facing the floor to sense the edge so that we can avoid a bad fall. The second example is to follow a line. In this case, we use a light sensor as a main sensor. First of all, it's very important to lower the attach point for the light sensor so that the sensor is much closer to the ground. In other words, the distance between the light sensor and the ground should be in the range of 5mm to 10mm. The reason why we do is that otherwise light reflected from the ground won't be effective enough for the light sensor to see. For the programming, we can make robot turn right when the light sensor sees the line and to turn left when it sees the surface out of the line. As the robot tracks the line, we may notice that robot is moving too slow. The main cause is the robot's gear. If the robot is moving too slow, we can find a bigger gear that is able to make robot move the fastest by trying out many times.