presented by:
Alyssa Ramos
Cynthia Kuykendall

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Abstract
This report discusses the modification of Parallax robots to create robot firefighters. It talks about how the robots get modified to navigate through a mock-up room and; how they detect heat and give some kind of indication that a high temperature has been detected. This report also discusses the requirements for this project and the tests or experiments that were done to achieve our goal. Results from these tests and observation will also be discussed and the difficulties or anomalies that were encountered throughout the development of this project.
Introduction
The robot firefighter project came about because we have had experiences with the Parallax robots (the Boe-Bot and the Sumobot) before. Two versions of this robot are made, one using a Boe-Bot, and one using a Sumobot but both Parallax robots consist of major components such as the temperature sensing unit using the Parallax DS1620 digital thermometer IC, and alert unit that combines visual and sound signal. The robots have the capability of maneuvering around a mock-up house to simulate real-life environment consisting of walls and rooms.
The main goal is to have an autonomous robot that moves about on the ground while taking the temperature of its surroundings and alerts the user when it detects heat (programmed by the user, acting as a thermostat). Due to time constraints, we were not sure whether we could add a device that will simulate putting the “fire” out. We were able to add this feature at the last minute using a PWM fan circuit for the Boe-Bot and regular DC motor mini-fan for the Sumobot.
Top Down Approach:
We took the approach of deciding what we wanted the robot to do and then dividing the work into different modules. We needed sensor modules, decision modules, alert modules, and movement modules. The modules had both software and hardware for each type. So after the circuits were designed and tested in hardware, the software needed to be coded and tested. Finally the functional tests were run on the experimental maze and hardware was redesigned and the software was debugged and redesigned.
Major Modules and Assignment of Functions:
1. Heat Source: Ordinarily a candle, but in the interest of safety and economics an incandescent bulb and reflector or a halogen lamp were used.
2. Environment: A miniature model of a simplified house maze served as the experimental environment.
3. Search: At first a dead reckoning program in PBasic that follows a preset path was employed due to lack of IR sensors, after IR sensors were added to the Boe-Bot an object avoidance program searched the environment. Sumobot uses the wall-hugging mode with IR and photoresistor sensors.
4. Detection: The DS1620 temperature sensor IC from Parallax was used to detect excess heat.
5. Alarm: When the temperature goes over the programmed value the LEDs light up and the piezo speaker sounds an alarm. Sumobot has a flashing reflective light and fire alarm circuit.
6. Control: The PWM fan circuit cools down the air. Sumobot has DC motor mini fan.
Testing Approach:
Performed the experiments from Parallax What is a Microcontroller. Performed the experiments from Parallax Basic Analog and Digital. Tested the piezoelectric speaker using freqout. (See Piezo Speaker circuit.)
Tested the DS1620 Digital Thermometer and Thermostat using program DS1620.BS2 from Parallax. (See Appendix for Specification Sheets.) Using unmodified program from Parallax, thermometer displayed temperature at one-second intervals on the PC screen in Celsius and Fahrenheit degrees. Tested the temperature sensor with an incandescent light of 100 watts. The temperature slowly increased from about 72 degrees to 82 degrees very slowly. The temperature went down slowly when the light was removed. The temperature went down more quickly when air was blown across it by mouth.
Tested the reaction of the sumobot robot to bright, hot light with mixed results at first. At first the robot wouldn’t turn on. Changed the batteries. The sumobot acted erratically. The manual was consulted and steps taken to reset robot. Robot begins performing as expected. When the light source came from above the robot acted normally moving along the wall (wall hugging mode). When the light source was placed directly in front of the robot it stopped. Further testing showed that a foot placed in front of the robot made it stop, and turn to avoid it, and then it resumes wall hugging. Decided that the reason the robot stopped when the light source was directly in front of it was because it saw it as an obstacle with its IR sensors.
Tested the servo run-time of robot to determine number of pulses needed to move forward a certain distance. Run program that moves robot forward for one second. Use ruler to measure distance moved. If robot moves 8 in/sec then the time it takes to move 20 inches is time = (20in/(8 in/sec)) = 2.5 sec. The number of pulses output in one second by PULSOUT from a Boe-Bot is 40.65 pulses/sec. So to travel 20 inches the program will ask for approximately 2.5 sec x 40.65 pulses/sec = 102 pulses.
Researched on the internet to find out how to design a fan circuit. Pulse width modulation is used to lower power consumption and prevent overheating. Built separate PWM circuit on another protoboard and tested it with LED. Result flashing light.
Interface Description:
One interface is the serial cable and computer. These tools enable the user to see the temperature being measured, the brightness of the light, the frequency output of the piezo speaker, and the movement subroutine.