| Pyro :: Fire Fighting |
| Tuesday, 05 October 2004 | |
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This is my third Autonomous Machine , equipped with a controller and a hell lot of IR sensors and some intelligence too. Pyro took First place competing with four other contenders. [Details at end of thispage] Pyro was run by the Sumo11 Contoller
This project discusses the development of a machine, capable of finding it's way through a maze of rooms, searching for a fire and extinguishing it. Though the scale of the machine is comparatively small and it's ability to put out a fire with the help of a fan may not be suitable in actual environments, the basic idea, structure and navigation skills can be employed in real situations.
Competiton Details Competition: IEEE – ISSAC 2003 College: Thadomal Sahani Engineering College Date: 5th October,2003 Robotics'Competition Level: LEVEL3 Autonomous Fire Fighting Competition
Competition Layout The purpose of the machine is to search for a fire in any of the five rooms and put them out. Candles are used to simulate a fire .Candles in any of the 3 rooms out of five are lit. The robot had to search all the five rooms to detect a fire .Priority of the rooms depended on the machine algorithm. The quickest machine to find all the candles and extinguish them is the winner.
Structure
Controller/Processor The Heart of the machine is a Sumo11 Controller with a Motorolla 68HC11
operating at 8Mhz. Click here to order it. The Sumo11 is similar in working as the Handyboard Loading the program into the controller The controller can be programmed via the PC's serial port.The program is written in a software known as Interactive C and the same is used to upload it to the Board
Motor Drivers The Motors for the main drive wheels are driven by Texas Instruments' SN754410 H Bridge driver.
Current source per channel is around 600mA. Click here to get the datasheet The Fire Extinguishing Motor is driven by an L293D. Click here to get the datasheet
Sensor Layout
In order for the machine to navigate through the arena, a line is provided,connecting each room.The line is a highly reflective silver taoe placed on the dark background of te track. There are a total Eight sensors onboard The different configurations are as follows: Line Following Sensor Array This array consisted of a total of six sensors.Their aim is to track the line leading to each roomas well as the junctions consisting of 2 to 4 intersecting lines. Their distribution is as follows: Four front Tracking sensors. Two middle Tracking sensors Front Obstacle detector/Room Detector This detector is used to sense the Candleplaced in the room. Flame Detector This detector checks the presence of a flameafter it has entered the room
Sensor Details All the sensors used on the machine are infrared sensors running at 5V dc. Since the range requirement was minimal[less than 5 cms],the sensors are not Modulated. Sensor Circuit
The sensor circuit is constructed so that it can handle a maximum of 8 IR sensors. Two comparators [LM324] are used ,to set the thresholds,nominally at 2.5V. The reference voltage can be set using a potentiometer. The basic circuit can be found here by Plermjai Inchuay Sensor connections to the controller. The Line following and the Front Obstacle Detector are connected to the digital ports through the signal conditioning circuit. The Flame Detector is directly connected to the analog port ,to detect varying candle light intensities.
Drive System and motors The drive system consists of two motors ,each controlling one side of the machine.The working is similar in priciple to "BattleTank" Steering. The Third supporting wheel is a castor wheel ,placed at the back of the machine. This configuration allowed the machine to turn on it's own axis with minimal turning radius. Motors The motors used were constant speed 30RPM DC motors at 12V The Fire Extinguisher Since competition rules required that no fluid be used on the track,Pyro used a fan connected to a high speed DC motor around 5000RPM The motor driver used was a L293D. The "Fire" Program goes like this:
Power Supply The robot had to be wholly autonomous with no cables from outside. It had a total of 5v batteries.Their distribuition is as under.
The sensor board has the boltage regulated to 5V The controller board has the same. The Drive motors get full 9V.
A snap of Pyro and his competitors
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