EET 419
Team 4

Problem


Goal


Counts number of seats occupied and if bus is
available for more passengers
Assignable


Pressure sensors built into seats will be
connected to a microprocessor and will
determine and display if the bus is at max
capacity, and will notify when someone has
left their seat during the bus ride.
Measurable


to design and build a pressure sensor system
that will detect how many people have
boarded onto the bus, if the bus is full, while
alerting the bus driver whether someone is
out of their seat during duration of the ride.
Pressure sensor, programming, designing system
Realistic

Sensors are cheap, programming is relatively
easy
Time



Program can count the number of seats, alert
when passenger has left their seat during
motion of the bus, alert when bus is full.
Objectives





based- Initial prototype can be made in
months; final project can be installed within
few weeks.
Success

Specific


correctly identifying the occupancy of a
passenger bus and that the passengers
remain safely seated throughout the extent
of the ride.

Accurately count number of passengers on a
bus
Making sure all riders are safely seated during
ride
Alert when the bus is at maximum capacity
Determine between one and two passengers
per seat
Obstacles



Precisely alerting driver that passenger is out
of their seat
Maintain a proper count of passengers on
board during length of ride
Being able to tell the difference between one
or two passengers
United States Patent Number:
8285454
Inventor:
Peter Norton of Farmington, MI

Pressure sensor system used to create the
classification of type of object in a car seat
and its position on the seat.
 It also calculates the weight of the object.
 Determines whether the seat belt is latched.
 Based on type of object, decides whether the
airbag system should be turned on or off.

The System Claims:
 To have sensors that respond to distance using a
reference location to the actual location of the
object, there by classifying the object into
categories.
 To have categories of the object in normal seated
position or object in other position.
 To have categories of person or object.
 To have sensor to define object as a person or an
infant car seat.

The System Claims:
 To have sensor to recognize whether the seat is
occupied or vacant.
 To have categories defining object as child or
adult.
 To determine, based on object data, if airbag
system should be on or off.

This system provides means of classifying seat
occupants into 3 categories:
 Adults
 Children
 Cargo
If the object is an Adult, the system accounts for
person’s location on the seat.
 Depending on the type of object the system
determines whether airbag system should be on
or off.


Research and find all components







Pressure Sensor
Micro controller
LED Display
Operational Amplifier
Order components
Est. time: 1 week
Est. Cost




Op Amp: $ 4 each
Micro Controller: $6
LED Display: $1.50
Pressure Sensor: $2 each

Design circuits for different parts of the
network
 Create circuit for pressure sensors
 Create circuit for LED Display
 Create circuit for Micro Controller



Implement circuits into overall network
Test and refine at each stage
Est. time for each stage: 2-3 weeks

Create program for the Micro Controller
 Test with individual parts of the project

Est. time: 4 weeks
Malfunction
Connection
Problems
Pressure
Sensor Breaks
Design does
not work
Op Amp burns
up
Faulty Pressure
Sensor
Connection
Problems
Faulty Display
Interfacing
Problems
Connection
Problems
Likelihood Consequences
Pressure Sensor Network
2
Microprocessor
does not
receive data
1
Pressure sensor
does not send
data
2
Sensor network
does not
function
properly
1
Microprocessor
does not
receive data
1
Pressure sensor
cannot be
used.
LED Display
2
LED Display
does not light
up.
1
LED Display
cannot be used
Drive/Park Condition
3
Microprocessor
does not
receive data
from vehicle
3
Microprocessor
does not
receive data
from vehicle
Severity
5
Connection
Problems
Faulty Buzzer
2
1
5
5
3
Faulty
Microprocessor
Connection to
System
Buzzer
Buzzer does
not activate
Buzzer cannot
be used
2
3
Microprocessor
2
Microprocessor
cannot be used
5
2
5
4
Microprocessor
does not send
or receive any
data
Coding
Microprocessor
does not
receive data
Receiving data
from Sensors
2
3
Code for LED
Display
2
LED Display
does not work
properly
3
4
Code to
Lock/Reset
Counter
2
Program
cannot stop or
reset counter
3
Calculate
weight ranges
2
Program
cannot
determine if
seat is occupied
3
3
4
5
Determine if
bus is
full/empty
2
Program
cannot
display if bus
is full or
empty
3
Risk Matrix
Code for
Buzzer
2
Buzzer does
not activate
2
A/D
Converter
2
Microprocess
or does not
receive data
from
peripherals
2
Likel
ihoo
d
3
Construction
Cannot find a
part
3
Must find a
different part
3
Part is
expensive
2
Must find a
less
expensive
part
4
Part is late
2
Must wait for
part to arrive
4
3
6
2
6
3
1
1
Severity
Parts to Test
How to test
Pressure sensor code
Write and test code. Connect sensors to microprocessor, and verify that
it works.
LED display code
Write and test code. Connect LED to microprocessor, and verify that it
works.
Lock/Reset Condition code
Write and test code. Connect switch to microprocessor, and verify that
it works.
Buzzer code
Write and test code. Connect buzzer to microprocessor, and verify that
it works.
Circuits for individual parts
Design and simulate in Multisim. Build and test circuits.
Overall circuit
Simulate in Multsim. Connect all pieces together, apply voltage, and run
program.