Abstract
This project attempts to address the need for a self-contained home
security system. Currently, home security systems require many costly
components and a complicated installation process. Two basic types of
systems are currently available. The first is a wired system. One
drawback is that installation of a wired system can take a lot of time and
money. Another drawback is that it is a permanent part of the home. If
the owner moves, the security system must stay. The second type of
system is a wireless one. These components for this are also costly.
Wireless systems are more mobile, but they require batteries which
must be changed every so often. The purpose of the proposed system
will be to eliminate the drawbacks of both wired and wireless systems.
The proposed system will consist of a single unit, which will monitor
the home for various hazardous conditions.
Hardware Theory of Operation
Four 24V DC gear motors will be utilized for locomotion. The
motor driver will be a commercially assembled part that provides
the ability to control the motor's speed using PWM. It will
receive the PWM signal from the MCU and then output the
driver current to the motor. Each driver will be configured to
drive two motors out of the four. In this manner, we will be able
to turn the robot on a time and navigate through the environment
with precision. This is important when implementing a mapping
algorithm that requires accurate movement. Fuses are
implemented to provide over current protection to keep the
motors safe. Each of the motors will be fitted with a 71:1 gear
reduction ratio. The theoretical rating for these motors will be 91
RPM at no load, a rated torque of 3.1 kgf-cm, and a rated current
of less than 250mA.
Safety concerns on the robot will be addressed with the use of a
mechanical ESTOP. A mechanical push button will be utilized in
tripping the circuit breakers connected to the output of the power
sources. Thus, once the E-Stop is pushed, power to all electronic
components and motors will be cut off, and the robot will
suspend motion.
The sensors that will be used on the Surveillance Robot is a
Carbon Monoxide sensor, a UV sensor, a audio sensor, a
gyroscope, and proximity sensors. Using information from the
gyroscope and the proximity sensors, the robot's position can be
determined. Using information from the CO, UV, and audio
sensors, alarm conditions can be detected. Data from the sensors
is amplified to the MCU's operating voltage and is processed in
the MCU for alarming the user via transceivers and for
locomotion. The MCU will communicate with transceivers using
SPI protocol.
The robot will be powered by the combination of a 24V battery
and a 5V battery. The batteries are chargeable and will be charged
by a 24V charger and a 5V charger. A power plug can be plugged
into the standard 125V, 60Hz and the voltage will be conditioned
by both the battery chargers so that the batteries can be charged.
Surveillance Robot
Marketing
Requirement
Megel Troupe – Project Leader
Andrew Biddinger – Software Manager
Roger Zhang – Hardware Manager
Nathaniel Fargo - Archivist
Software Theory of Operation
The basic idea behind this layer of software is that the sensor data
is read from the Sensor I/O module and used in a finite state
machine. It will send control signals to the Locomotive and
Warning modules depending on what state it is in. The
locomotive module will then take these control signals and
determine exactly how far to move the robot. The warning
module will also warn the user when a threat is in the proximity
of the robot and log this information.
State Machine Theory of Operation
The following state diagram describes the different
states that the system can be in. The system starts off an
in initialization state where the counters and the
registers are initialized. It then moves to a processing
state which reads the values from the sensors and
determines what to do next. If there is a hazard, the
state is moved to warning and the warning module is
notified. If there is not a hazard detected and the
counter for number of movements is not at the max
value, the state is moved to the Move state and the
Locomotive module is notified of which direction to
move to. If the counter value is at its max value, the
state is moved to Hibernate where the system will rest
for some prescribed amount of time.
The base dimensions
The size of the robot should be small
should not exceed 50cm x so that costs are low, it can navigate
50 cm x 30 cm.
through normal household spaces, and
it is easy for the user to operate.
1, 2, 3
The mass should not
exceed 10 kg.
The weight of the robot should not be
large so that costs are low, it can be
driven without using a lot of power,
and it is easy for the user to operate.
1, 2, 3
The height of the entire
robot should not exceed
60 cm.
The size of the robot should be small
so that costs are low, it can navigate
through normal household spaces, and
it is easy for the user to operate.
2, 4, 6
The movement speed
should be .2 m/s ± 10%.
The speed should be reasonably rated
for safe, autonomous movement over
various surfaces.
6, 9, 10, 11
A fully charged battery
The battery life should be sufficient
should completely deplete that the robot can operate
in no less than 12 hours. autonomously for a reasonable amount
of time. It should also be able to back
up and transmit data within this time as
well as have capacity for more sensors
(future expansion).
8, 11
Must be able to react to a In order for the robot to transfer data in
notification of a hazard in “real” time, it must be able to react to a
under 10 seconds.
hazard quickly.
8
Must be able to detect
carbon monoxide levels
as low as 45 ppm.
8
Must be able to detect the The robot should be able to determine
presence of a candle fire if there is a fire or not, and alert the
approximately 3 meters
user.
away.
8
Must be able to detect
sounds at the frequency
of breaking glass.
(frequency to be
determined through
testing).
5, 7, 9
Must be able to send data The user should be able to tell the
to a configurable, secure robot where they would like a data log
location
to be kept without too much trouble.
Initialize
Hibernate
Cou
nte
r re
ach
es m
ax
tion
Software Block Diagram
ing
rn
Wa
Processing
i
ond
C
Warning
No
W
Co arni
ndi ng
tion
Justification
1, 2, 3
Design Team 09
• 
• 
• 
• 
Engineering
Specification
Carbon Monoxide levels between 1
and 70 ppm are usually not harmful.
Levels over 70 ppm can cause
noticeable symptoms of carbon
monoxide poisoning. Levels over 150
ppm can be lethal.
Move
Sleep
State Machine Diagram
The robot should be able to determine
if there has been a break-in and alert
the user.
Marketing Requirements
1.  The robot should be relatively inexpensive.
2.  The robot should be able to navigate across most types of floors seen in
modern homes.
3.  The robot should be intuitive and easy to use for the average homeowner.
4.  The robot should include safety mechanisms.
5.  The robot should require minimum amount of setup for basic use.
6.  The robot should move autonomously.
7.  The robot should be configurable by the user.
8.  The robot should be able to sense multiple hazards such as movement,
sound, and smell.
9.  The robot should be capable of backing up data.
10. The robot should be expandable for increased coverage and security.
11. The robot should be capable of transmitting real-time data over some
medium.
Hardware Block Diagram
• 2012-2013 Senior Design Capstone Project • Dr. Igor Tsukerman, Faculty Advisor • Mr. Gregory A. Lewis, Senior Design Coordinator • Department of Electrical and Computer Engineering • College of Engineering • University of Akron •