1	"Science Fair" Science Fair Project
2	Overview Problem Statement and Hypothesis Approach Results Lessons Learned Conclusions
3	Problem Statement Using a robot and an optical guidance system, to what extent will the robot be able to move payloads to a destination area? What guide track patterns are more effective in controlling the path the robot uses? What is the relationship between speed and accuracy in enabling the robot to perform the experiments? How well can the robot move the payloads?
4	Hypothesis We think the robot will successfully follow the tape routes. We are not sure if the robot will be able to move all of the payloads because of the weight. A faster robot will be able to complete the task sooner.
5	Approach / Materials / Resources Approach Using a Lego MindStorm Robotic kit to design and build a wheeled robot. We programmed our robot using a PC and the Lego RCX software on CD. The test course for the robot to follow is built using foam board and black tape tracks. The weighted payloads are made from Lego blocks. The robot is run over the course and results recorded on video using a digital camera. Materials / Equipment Mindstorms Robotics Invention System 2.0, white foam board (36 by 48 inches), eight coin weights (quarters), black electrical tape, a pencil, scissors, green and blue construction paper, a bright light, a computer, a digital camera. Resources / Research Books - Robot Invasion by: Dave Johnson (Damascus library), and The Lego MindStorm Robot Programming Book (from Lego). Web Sites – Online tutorials, videos and examples http://mindstorms.lego.com
6	Robot Construction The robot was built using a basic design and then modified. The robot consists of a RCX unit, four wheels, two motors, two sensors, and an arm attachment. We took a picture of the robot as shown to the right.
7	Arm Detail: normal payload
8	Payload We made the payload out of Lego bricks and eight quarter coins as weights. We put the Lego bricks together to form a box with a hollow space in the center to put the quarters inside. We tested less coins and added coins until the touch sensor on the robot arm consistently detected the payload.
9	Testing Sensors Touch sensor program Video of robot in action
10	Light Sensor The light sensor is what helps the robot follow the black lines. It is a blue brick located in the arm attachment. The light sensor is facing downward. It can detect different colors with light and dark You can view the sensor readings in the RCX window
11	Light Sensor Characteristics Sensitivity - Color / Sensor Height
12	Mission 1 – Directed Control We used the touch sensor to find the payload. The robot turns left until it finds the black line. Then the robot turns left and follows the line until line ends. Then it goes right to deliver the payload.
13	Mission 2 – Automated Control
14	Course Considerations Robot has to work harder on courses with more sharp turns Movement has to be short to avoid losing track of lines on the course, so is slower To make robot last longer – make delivery of payload less complex Electric motors have to work very hard, spinning forward, back, and stop.
15	Mission 2 – Automated Control Improving Program control by allowing two things to happen at once Uses event handlers in the RCX Sensors cause events when they detect changing conditions
16	Using Events The computer uses sensors to control when and how things happen: Light dark Light bright Touch pressed Search for line See green pad
17	Program Course Speed Curved course Event method Repeat method
18	Results Our results were pretty much as planned. The robot was able to follow the tapes routes. Even though we made many different routes. We used the built-in RCX timer to measure how fast the robot completed each course test-run. There was a lot of trial and error in the programming. We did have to make some changes like adding a green pad, at the end of each course so the robot could know when to stop. The RCX view sensors window helped a lot. Equipment Performance – The equipment performed very well except for one detail. When we were doing the curve course experiment with the second program it caused a motor to overheat and fail. That meant we had to take everything apart, and send the kit back. This was a major set back. It meant my sister and I had to start over and re-build the robot and re-install the software.
19	What we learned Direct control program Inline program steps using repeat Event driven program using sensors Course details – width of lines, tightness of curves, speed of robot, sequence of turns, importance of positioning in turns (use of reverse), how to detect color. Control details - how often it checks sensors, interrupt driven sensors, using repeat loops Exact control with recovery compared to good-enough control (robot can return to start point verse just delivering payload)
20	Conclusion The robot completed our objective, although we made many mistakes and adjustments. Finally, we have a successful program and a good robot design. Our results compared to the hypothesis were nearly correct. Our robot was able to follow the tape routes successfully. However we found the robot was able to push the cargo with ease where we said originally it may have problems. Also we thought speed would be important but we found that control and course features controlled the time taken to deliver payloads instead.
21	Thank you!