Auto-navigation of Unmanned Helicopter to Detect and Extinguish Forest Fire

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Page | 1 CMPE 691 – Wireless Sensor Networks Auto-navigation of Unmanned Helicopter to Detect and Extinguish Forest Fire University of Maryland Baltimore County December 17, 2010 Jerome Stanislaus ([email protected]) Abstract A Wireless Sensor Network application has been presented that is capable of detecting forest fires by using fire sensors. When there is an event sensed, the sensor communicates with the base station, which then sends control signals to a helicopter. The helicopter will go to the particular sensor and extinguish the fire. 1. Introduction A Wireless Sensor Network (WSN) consists of spatially distributed autonomous sensors to cooperatively monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants [1]. Recent advancements in wireless sensor networks have made them grow beyond the military applications that they were initially designed for to the world where humans work and live: buildings, cars, homes, etc. The biggest advantage gained from these advancements has been the fact that the sensor networks are now able to work with very little human intervention. This advantage has been utilized in our project wherein forest fires are detected automatically by deploying fire sensors that operate wirelessly. If one of the sensors detects a fire it sends a signal to the computer. The computer then controls the helicopter and sends it to the particular sensor. Thus, with minimal human intervention the fire is extinguished.

Transcript of Auto-navigation of Unmanned Helicopter to Detect and Extinguish Forest Fire

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Auto-navigation of Unmanned Helicopter to Detect and Extinguish Forest Fire

University of Maryland Baltimore County

December 17, 2010

Jerome Stanislaus ([email protected])

Abstract

A Wireless Sensor Network application has been presented that is capable of detecting forest fires

by using fire sensors. When there is an event sensed, the sensor communicates with the base

station, which then sends control signals to a helicopter. The helicopter will go to the particular

sensor and extinguish the fire. 1. Introduction

A Wireless Sensor Network (WSN) consists of spatially distributed autonomous sensors to

cooperatively monitor physical or environmental conditions, such

as temperature, sound, vibration, pressure, motion or pollutants [1]. Recent advancements in

wireless sensor networks have made them grow beyond the military applications that they were

initially designed for to the world where humans work and live: buildings, cars, homes, etc. The

biggest advantage gained from these advancements has been the fact that the sensor networks are

now able to work with very little human intervention. This advantage has been utilized in our project wherein forest fires are detected automatically by

deploying fire sensors that operate wirelessly. If one of the sensors detects a fire it sends a signal

to the computer. The computer then controls the helicopter and sends it to the particular sensor.

Thus, with minimal human intervention the fire is extinguished.

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2. Overview Consider a forest where sensors are randomly deployed all over the region using any random

deployment method. Now, if a forest fire is detected the sensors send a signal to the command

node which is connected to a computer via USB. This command node and the computer together

serve as a base station. The computer then sends out signals via its parallel port to control a

helicopter, which is directed towards the fire. The helicopter may be equipped with fire

fighting tools that will help subdue the forest fire.

Fig. 1. Diagrammatic representation of the application

3. Implementation Our project implements a Wireless Sensor Network that can also be extended to a large scale

implementation. The wireless network is created by separate motes or nodes which are equipped

with a sensor board. When activated, the sensor node is able to communicate to the computer.

This communication takes place in a multi-hop fashion. The motes used are manufactured by

Crossbow Technology and are called the Crossbow IRIS motes. The sensor boards are the MDA

100 boards, also manufactured by Crossbow. So, the entire network can be represented as shown in Figure 2.

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Fig. 2. Project representation The sensors are programmed individually first and then deployed (the source code for the same

is attached at the end of this report). A location map is created of the sensors. The computer

knows which sensor is activated so it is able to point the helicopter in the right direction. After

the deployment, we wait for a sensor to trigger the signal to the helicopter. When a signal is

received, the chopper flies towards the particular sensor node.

We have created a circuit that

is connected to the parallel port of a computer. The circuit is

shown in Figure 3. The transistors Q1 and Q2 are 2N3053, n-p-n transistors.

Fig. 3. Circuit to interface with parallel port

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Inside the helicopter’s remote control, the directional control stick works based on two separate

variable resistors. The first variable resistor controls the front-back movement and the second

variable resistor makes the helicopter turn clockwise. For example, considering the variable

resistor that controls the back propeller of the helicopter (i.e. front-back movement), we observed

that the chopper moves forward when the resistor is at its minimum position and stays stationary

when the resistance is maximum. So, by bypassing the variable resistor, we apply either a low

resistance or a high resistance across the terminals. We used a BJT as a switch in the circuit. A

BJT switches according to the voltage applied at its Base terminal. The Collector and Emitter are

connected to the ends of the variable resistor. So, when +5V is applied to the Base of the BJT,

there is a connection between the Collector and Emitter terminals. This provides a path of least

resistance between the Collector and Emitter terminals, implying a low resistance is found on the

variable resistor. Hence, the chopper moves forward. When 0V is applied at the Base, there is no

connection between the Collector and Emitter. This provides the high resistance that’s required.

So, the chopper stops moving forward. To reduce the Base current, so as to save power, we

added a heavy resistor on the Base terminal. Two data ports from the parallel port of the

computer supply the voltages. 4. Simulation

For the simulation, the time the helicopter takes to traverse 10 feet was recorded. This was done

to know how long the parallel port must send logic “one” (i.e. +5V) to the Base. The helicopter

is first controlled manually to take it to a steady position and height after which the sensor is

activated. The computer gets the signal from the sensor via multi-hop following which it

calculates the distance the helicopter must travel. It then sends the corresponding signals to the

Bases of the transistors mentioned previously. 5. Future work

In the future, we propose that the application be automated further and the helicopter be entirely

controlled by the computer. The sensor network could be formed in a different manner so as to

optimize the coverage of the nodes.

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6. References

[1] Definition of WSN.http://en.wikipedia.org/wiki/Wireless_sensor_network

[2] Image of laptop. http://blog.loaz.com/timwang/index.php

[3] Image of Motes. http://neo.lcc.uma.es/staff/guillermo/index_files/investigacion/redes