Pyro  :  Autonomous Fire Fighting Machine

 

 

 

 

 

 

 

 

 

 

 

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 page]

This was possible mainly because of the Sumo11 Robot Controller [go here: http://www.sorobotics.org/sumo11.html].

or here to order [http://www.1sorc.com]

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.

SEE THE NEW UPDATED HOMEPAGE :: PYRO:: AUTONOMOUS FIRE FIGHTING ROBOT  Click here

 

Competition Details

 Competition:                             IEEE – ISSAC 2003

 College:                                    Thadomal Sahani Engineering College

 Date:                                     5th October,2003

 Robotics’ Competition Level: LEVEL 3 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 And Material

 

§         The structure consists of two platforms separated from each other  by Mecanno strips

§         The stack design is used to save space as well as to ease connecting cables to and from

       different circuit boards.

§         The base of the machine is made of Hylem, a very light material having very good strength.

§         The whole robot runs on 3 wheels .Two main medium sized wheels are used for steering

      and forward / backward motions. The third central wheel is a castor wheel, used for

      supporting the machine.

§         The sensors are held in place using standard mecanno strips.

The front end has a Fan to blowout the fire. The Fan motor is held by a gas light holder

 

Controller/Processor

The whole machine is controlled by a Sumo11 Robot Controller with a

MOTOROLLA 68HC11 microcontroller operating at 8 Mhz .

 [go here: http://www.sorobotics.org/sumo11.html] here to order [http://www.1sorc.com]

The Sumo11 controller works in a similar way as the Handyboard.

 [go here: http://www.handyboard.com

 It has the following specifications.

  • On board standard serial port
    Low power monitor & reset circuit
  • Right & Left H-bridge motor outputs
  • I/O ports  
      • 7 analog inputs
      • 8 digital inputs
      • 1 selectable I/O
      • 1 digital output
      • 1 modulated dual IR output
      • 2 pwm motor outputs
  • LED motor direction indicators
  • 32k non-volatile RAM
  • 2x16 character LCD display
  • Programmable analog thumb wheel
  • Programmable Start and Stop buttons
  • Piezo beeper
  • Interactive C© compatible

 

Loading the program into the Microcontroller

The controller can be programmed through the Serial Port of the PC/computer.

A specific software , known as “Interactive C” , is used to load the program as well as code and debug  the onboard program .

 

 

Motor Drivers

The Motors for the main drive wheels are driven by a Texas Instruments’ SN754410

H-bridge Driver. Current source per channel is about 600mA.

It has the following features:

  

The Fire Extinguishing Motor is Driven by a L293D H-bridge Driver. Current source is about 600mA per channel

It has the following features: 

 

 

 

 

Sensor Layout

In order to enable the machine to navigate along the track, a line is provided, connecting each room.

The line is a highly reflective Silver tape placed on the dark background of the track.

 There are a total of eight sensors onboard.

The different configurations are as follows: 

This array consisted of total of Six sensors. Their aim is to track the line

leading to each room as well as the junctions consisting of Two to a

maximum of Four intersecting lines.

 

Their distribution is as follows:

·        Four Front tracking sensors

·        Two Middle tracking sensors.

 

This detector is used to sense the Candle placed in the room

(which also tells the machine that it has entered the room and to

start searching for the fire)

 

This detector checks the presence of the flame after 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 (i.e.  To only detect the “reflective line”

and the front obstacle), the sensors are not Modulated.

The range accomplished here was around Two Inches.

Sensor Circuit

The sensor card is made to handle a maximum of 8 sensors.

This is accomplished by using two comparators with a voltage reference

of 2.5 V.The comparators used are LM324.

The reference voltage can be set by varying a 10K potentiometer.

The basic circuit used can be found here [www.kmitl.ac.th/~kswichit/LFrobot/LFrobot.htm]

by Plermjai Inchuay

 

Sensor connections to the controller

Since the Line Following and the Front Obstacle Detector are only required to give a 1 or 0 signal, they are connected to the digital ports of the controller.

However the Flame Detector has to detect a varying candle light, a digital signal reading from it is not possible. Hence it is connected to the analog port of the controller. The analog thresholds are preprogrammed with enough error margins so that it gives a correct flame detection reading

 

 

Drive System and Motors

The Drive system consists of two motors, each controlling one side of the machine.

The Steering is similar to a “Battle Tank” type steering.

Two wheels one on each side of the machine are connected to the motors.

A  Third Supporting Castor wheel is placed behind the machine.

This configuration allowed the machine to turn on it’s own axis with minimal turning

radius.

Motors

The motors used are  30 RPM constant speed DC motors at 12 V.

The Motors were geared down internally giving a large torque to weight ratio.

 

 

 

 

Fire Extinguisher

A 4 Blade fan is used to extinguish the candle Flame.

The motor is drive by an L293D motor driver at 9v.

 

When the machine detects the candle ,it switches on the Fan for 10 seconds.

It then checks the flame sensor whether the Flame has been extinguished.

If not ,the Fan is turned on again.

The loop continues until the Flame has been blown out.

 

 

Power Supply

Since the machine had to be wholly autonomous carrying it’s own power supply,

It had a total of five, 9v batteries. The battery distribution is as follows:

 

The sensor board is regulated at 5V using a 7805.

ir.jpg The same is done for the controller board.

The drive motors get a full voltage of 9V (2 batteries in parallel).

 

Competition

Few snaps of the competition layout with Pyro and his Competitiors. I knew only Mandar's machine .I don't know the names of the other too. Mandar's machine was running on a PIC16F84A The other two were powered by Atmels'. Mine by a Motorolla 68HC11. [click the snap for a larger Picture]

 

 

 

If you have any queries u can mail me at:  gerryseq(AT)rediffmail.com

 

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