Nt1310 Final Project Report

Introduction
Problem Description
The goal of our final project was to build a car that has the following two functions: 1) follow a path made by a white line 2) respond to a sound from the environment by stopping or starting itself. The project was built on the chassis used in the previous labs, and utilized two Line Follower sensor and one microphone provided in the lab kit. Besides, an Arduino Redbeard was used as the microprocessor of the car. The car was expected to power itself and demonstrate considerable reliability while meandering along the white line.
Design Concept To accomplish the task of line following, the two Line Follower sensors were placed on the two sides of the front of the car. They were used to detect the
Without proper measures to decrease the amount of noise, the signals from the microphone would be so interfered that the microprocessor would be unable to detect the presence of any sound from the environment. The biggest source of the noise were the motors. To decrease that, the power source of the microphone circuit had to be separated from that of the motor driving circuit. To complete this aim, a total of two pack of batteries were used, as the microphone was powered by its own set of batteries. However, that was not suffice to completely eliminate the noise in the circuit. Considerable amount of noise still existed when the motor started running, which was probably from Arduino board and from the batteries themselves. Without proper treatment the noise would still be able to cause an unexpected cut out of the motors, as they exceeded the threshold that turned the car on and off. Further filtration of the noise in the circuit was completed by the program that made decisions. The first step we took was to increase the voltage of the threshold, so that the probability of a noise reaching the threshold was significantly lowered. However, noise with extremely high voltage still existed. Therefore, another step was taken to enable the microprocessor to distinguish sound from the environment from internal noise. This was done by making sure the car only stops when the signal from the microphone exceeded the threshold twice in two consecutive readings. This method worked because the distribution of noise was sporadic and not continuous, which meant that there was little chance that it could maintain a high value in two consecutive readings of value. In contrast, the noise from the environment made to control the car could last a span of time, which was sure to pass this check and trigger the