Design_Optionsx - ECE Department Wiki

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Oct 26, 2013 (3 years and 8 months ago)

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1

ECE 403

Senior Design II

Options Considered Document

19 September 2012

Michael Anderson

Hendryk Herzog

Trevor Overby


2

Introduction

Many
businesses have a desire to retrieve sensor data remotely, log said data, and view it in a
meaningful way. This can be useful in many applications such as fleet management, soil
condition tracking, temperature tracking, or any other remote sensor that coul
d require
wireless monitoring. The end goal of the project is to have a device that can collect and
transmit sensor data to the cloud, with an application to access and display the data.

Previous Works

In order to better develop our product, we researched
what types of services and devices are
currently on the market. In our research, we found many examples of products that implement
solutions to the problem.

Starcom Systems Helios Fleet Management Unit


Starcom

Systems is a company that specializes in creating easy to use, practical wireless
solutions to manage and protect people, fleets, containers, and assets. The Helios fleet
management unit uses a GSM cellular network to transmit data to either a proprietary

software
or a user software. It is capable of having programmable events, speed restrictions, mileage
tracking, driver identification, perimeter alerts, complex alarm systems, emergency detection,
and many other features that are useful to fleet managemen
t.

This system uses a quad band GSM radio to function on a global scale. Different models also
have additional IO functionality, like a Canbus to communicate with the truck computer.
Starcom offers two different levels of this product, also turn key (com
plete) solutions and OEM
(hardware only) solutions so the user can provide their own software to handle data storage.
The turn key solution includes a cloud based application to monitor data. This product can fill
many roles a user needs in a fleet managem
ent scenario.




3


Starcom Systems Triton Container Tracking Unit


The Starcom

Triton container tracking unit uses a GSM cellular network to communicate
information about a shipping container and its contents. It can continuously monitor things like
acceleration, location, and temperature (in the case of refrigerated units). This un
it can also be
located even when there is no GSM network. This product shares the same software set that
was developed for the Helios fleet management unit. The enclosure for this unit is very
specialized for attaching to shipping containers.

Remote Temper
ature Monitor


This is a remote temperature monitor developed by Matt Tilchen. It uses a GSM cellular radio
to send temperature readings over SMS messages. It uses two 1
-
wire temperature probes to
read both air and pipe temperature in a summer home. This
allows the user to monitor


4

temperature to decide if the temperature is abnormal. Since this uses SMS messaging instead
of a TCP/IP system, it is much harder to interface with the cloud. The Arduino and SM5100B are
both powered with a 9V wall wart. This uni
t cost about $175, and had a $5 recurring fee to pay
for the SMS service.

Pedigree OneView

The technology reviewed here is the Oneview technology provided by Pedigree Technologies. It
is a solution to track the location and some conditions of heavy machine
ry, vehicles, as well as
tank levels when appropriate.

In general, the system collects information from provided hardware and sends this information
via the cellular network to the internet which then does some cloud computing on this raw
data. The end cu
stomer can then view this data and analysis in real time via any internet
browser that is connected to the World Wide Web.

The hardware unit(s) that are used in this system look similar to this:

.


Due to the usage of multiple different ports within the u
nit it has the capability to support a
large number of connected devices for versatile application usage. The system uses the
machine
-
to
-
machine (M2M) network to automatically update and maintain the data within the
cloud storage, so the customer is always

up to date on his large scale utilities. The OneView
system erases many of the headaches the consumers had before and it further optimizes the
customers’ profitability given time and a large enough sample space.

On the other hand the OneView system only p
rovides solutions for heavy machinery and
inventory management industries like construction, agriculture, transportation, and oil. In this
sense it is plausible to have a hardware unit that is versatile but larger in size.

The system does a very good job o
n the information presentation and user friendliness side of
things. One of the many faces of the possible ways of presenting the information to the user
looks like this:



5



(
Tank

management)


It is a very nice and easy to view interface which can be
accessed about anywhere and seems to
be easily customized.

Emerson Cell Link Adapter Station

This system is
designed for

monitoring temperature, water levels, and power outages in remote
locations such as a summer home or cabin. This device will call your
cell phone with
information about abnormalities in area it is monitoring. It requires its own
Bluetooth

enabled
cell phone to be wirelessly connected to it. When an alarm occurs, it uses that cell phone to dial
out to a preprogrammed number with informatio
n about the alarm. This device does not do
any data storage or computing, but is simply an alarm system that uses the cell network to alert
the consumer of alarms. The consumer can call the cell phone assigned to the adapter station
to get real time temper
atures, water levels, and state of power in the monitored area.



6


Big Picture

Based on what is currently on the market, we have noticed that a lot of ‘whole system’
solutions are available, targeting specific use cases and gathering data related to it. Som
ething
that is missing is a device that can be configured by the user to collect any type of sensor data.
Instead of relying on an external company to design an entire system, we could provide a user
configurable product to meet any need they could want. A
nother group of users who could be
interested in this is the
home brewer

or student user. They would require a very cheap and
configurable solution, since it could be used in any number of unique and novel applications.
We know that a market for this exist
s, as shown in the
Remote Temperature Monitor

section of
Previous Works.

Our solution should meet the following constraint priority to target these groups of users:
cheap, low power, generic, small area, and reliable. We have considered many different
design
issues for our product:



Connection Type

o

2G, 3G, 4G, TCP/IP, SMS

o

CDMA, GSM



Carrier Choice

o

Verizon, Sprint



Sensor and Communications interfaces

o

SPI, I2C, UART
(RS
-
485)
,
USB,
ZigBee



Application and Cloud Hosting

o

Google App Engine, Amazon EC2

o

Application

language

Sensor and Communication Interfaces


Our device
could use several different types of interfaces to communicate with sensors.
The interface should robust, reliable, and allow for additional sensor support to be added in the
future.




7

Method of Comm
unication
-

Serial Peripheral Interface

Advantages



Complete protocol flexibility. Can choose word size, message size, etc.



Simple hardware interface.
This result

in lower power, no hardware arbitration modes,
slaves use the master clock, and
transceivers

are not needed.



Only four pins are needed, with one unique CS per pin

Disadvantages



Need extra CS pin per sensor.



Prone to noise spikes.



Does not support hot plugging.



Long distance support is very
limited;

SPI is intended for internal use.

This
communication interface is a poor one for our needs. Sensors could be placed far away, so
we require a longer distance.

Method of Communication
-

I2C

Advantages



Only requires two pins to control several devices.



Low power.



Simple to implement protocol
.

Dis
advantages



Limited to four meters distance between devices
.

I2C is also poor choice of communication for this project.

The limited range of this standard
eliminates it from our pool of choices.

Method of Communication


RS485

Advantages



Large range, up to
4000 meters.



Low power devices available.



Only three wires needed for up to 256 devices
.



Can be implemented with a UART available on many microcontrollers,
signaling

is
handled by the driver IC.



8



Differential signaling allows for robust communication.

Disad
vantages



Current scales with the amount of devices on bus
.



Lower speed compared to other standards, depending on distance.

RS485 looks like an excellent candidate for our problem. It has excellent range and multiple
device support. The slowe
r signaling spe
ed should be a
non
-
issue, because our device is not
handling time sensitive data.

Method of Communication


USB

Advantages



Can power sensors with a USB cable
.



High speed communication
.



Widely used and understood by the public
.

Disadvantages



Limited range,
only up to 25 m.



Limited multi
-
device
support

would have to implement a USB hub.



Increased protocol complexity
.

With limited range and multi
-
device support, USB seems like a poor choice for the project. The
one nice advantage would be being able to power s
ensors over the USB cable.

Method of Communication


Xbee, Zigbee

Advantages



Wireless communication would be a nice feature.



Low power compared to other wireless methods.



Used in the ECE department and is well understood.



Multiple devices can communicate w
ith one
receiver
.

Disadvantages



Would cause extra interference that could cause problems.



Questionable range in certain situations.



Large board to board connectors take up valuable area.



Significant cost.



9

Zigbee would add an extra feature to our project, w
ireless sensor support. It would be fairly
easy to implement, and is already well understood within our department. Xbee is also a
vendor we have worked with in the past, so getting the devices will not be an issue. Using xbee
would add significant cost to

both the main board and the sensor boards (range from $15 to
$35 for varying features on the modules). Supporting both Xbee and RS485 will give users to
complementary features that will cover

many different user scenarios.

Cellular Connection Type

There a
re many different design choices to make when it
concerns

the cellular communication,
both on the hardware and software sides.

Cellular Connection Type
-

CDMA
vs.

GSM


The two main wireless providers in the USA today are Verizon wireless and AT&
T. Both of them
have over 105 million subscribers in the
cell phones

alone. They provide very alike services, but
do so in different ways.

First we have AT&T. They use

a standard called GSM (Global
System for Mobile
Communication) which utilizes the use SI
M cards (subscriber identification module cards) to
identify users. This enables for easy hardware changes if needed/wanted. It means that only
the communication channel (wireless communication channel) has to be opened and the
communications provider only

need the information from the SIM card not the hardware unit
itself. This makes GSM very
versatile

and very user friendly.

Due to historic events (the transition from 1G to 2G or from analog to digital communication)
the pre dominant communication protoco
l used in the USA today is CDMA. CDMA stands for
Code division multiple
accesses

and is provided by 5 of the top 7 communication providers in
the US today, including Verizon. CDMA
assigns

each hardware unit
its

own frequency spectrum
within a group of devi
ces to communicate over. Each of these groups has a code associated
with it which identifies the user as part of that group with a certain frequency. This allows the
provider to control network access and user identification. In turn this makes it very har
d to
change devices between providers as well as models if they are not certified by that specific
provider.

Within the scope of our project we were limited to use CDMA because it is predominant in the
northern
Midwest

and it was made easy for us to contac
t CDMA protocol providers like Verizon
Wireless.

Cellular Connection Type
-

2G
vs.

3G
vs.

4G



10

The biggest difference is the underlying structure between 3G and 4G. 3G is based on a cell
architecture (much like 2G and prior generations), but 4G is based on p
ackaging like the TCP/IP
the internet uses. The

packaging enables for much

faste
r

data transmissions and multitasking
for the user module (very much like using an internet connection). For the scope and usefulness
of this project heaps of data in quick
suc
cession

are not needed with this 4G is not.

It comes down to 2G
vs.

3G. 3G is a like 2G but due to better use of technology, channels,
frequency usage, etc. it has a much larger communication speed when compared to 2G. It was
made clear that 3G is about 1
0 times faster than 2G which allows for data transfer to include
audio and video files in larger quantities.
2G as

implied is the slowest and oldest of the three. It
allows for good data transfer as long as it is small data in
succession
. This means video
data
exchange is highly unlikely and slow (due to low data transfer rates).

This project allows us to utilize 2G for it provides the coverage and speed needed for us, but at
the lowest cost (higher communication speed results in higher costs). 2G and 3G ar
e still
compatible on the same network and are still provided and
largely

supported by Verizon as of
September 17, 2012.

Cellular Connection Type
-

TCP/IP
vs.

SMS

It is obvious that TCP/IP provides the possibility to send larger packages of data at a lower

cost
and it is one of the most common tools used for data transmission to a central location. We do
not need to communicate between to two hardware units but to a central station (the Cloud).

SMS is very limited in what kind of data can be send (160 chara
cters per SMS) and
its

cost is
rather high at about 11 cents per SMS. In return TCP/IP enables us to connect to the central
station easily and dual
communications (upload

and download from either end).

The decision here was made rather easy. We decided to go with the TCP/IP for communication
and cost purposes because if our maximum communication cost per month may be $10 dollars
per month we can get up to 1 MB of data for about $9 while 10 dollars only g
et us 90 SMS
which are at 160 char per
SMS 160
*8=1280 Bits or 160 Bytes; this is a total of 14400 Bytes or
14.0625 KB which is about 1.37% of 1MB of data with TCP/IP.

Carrier Choice
-

Verizon

Verizon offers a wide range of certified devices that can be use
d on their 3G network. After
meeting with a Verizon representative we were given a list of certified devices that we could
integrate into our product with a free test period. After we have finished our product, Verizon
engineers test it
against

their syste
m and use the information gathered to recommend the best
data plan for the product.



11

Below is a brief summary of the service costs.

Monthly
Access

MB Allowance

$8.99

1 MB

$10.99

2 MB

$12.99

3 MB

$14.99

4 MB

$16.99

5 MB


Advantages



High coverage in
US/Canada



Wide range of devices that can be implemented into products



Free trial period



Free certification



Potential Partnership with Verizon



Month to month payments

Disadvantages



Limited to CDMA

Carrier Choice
-

Sprint

Sprint does not offer certified devices but rather the service
of companies

that will supply you
with the hardware and the service to use it. Since we are developing our own service, we do
not need the service of another company. Unfortunately, this is whe
re the help of sprint ends.
When we contacted Sprint Customer Service, we were told that we could attend a conference
that could give us more information.
We do not have the time to attend a conference in
California because of conflicts with our schedules
due to school.

However,
we only needed
information about certified modems on the Sprint network, which Sprint did not offers us, but
in return they offered us names of companies that will provide these in part. This is not what
we are looking for and it do
es not help us with any part of the project, henceforth it appears
that Sprint is not fit to be our carrier of choice.



12

Disadvantages



Poor customer service



Not user friendly

Application and Cloud Application

Google App Engine

This choice was considered, but there would be a problem getting data to this server.
All TCP/IP
sockets are blocked from the Google App Engine sandbox. This would be a problem, because
that is what most of the cellular modems use to open external internet

connections. Another
hosting service we considered was
Amazon

EC2.

Amazon EC2

Amazon’s Elastic Cloud Computing
service is very similar to Google App Engine. It allows you to
run an app on the Amazon cloud, and use certain APIs and features built into the
service. Some
of these features, like databases and static IP addresses, will enable us to easily send and store
data on the cloud. A free version is available for trial with limited amount of CPU time. These
restrictions should be loose enough to test our

project on.

Application Language

Since
Amazon has made a Java SDK available for all of their web services, this would make Java
the natural choice for our application language. The SDK would include APIs for the EC2 server
and also the S3 (simple storage
solutions) database that comes with EC2. This would cut the
development time on the cloud application side.

Selected Approach

Method of Communication

We selected two forms of sensor communication for this project. They are RS485 and Xbee.
RS485 is perfect
for this project. The long distance communication, along with allowing multiple
devices on one transmitter, will suit this project perfectly. Microprocessors (such as the
PIC24FJ64GA004) come with this as a
built in peripheral, as a bonus.

The Xbee is a bo
nus feature we plan to implement to include more options for a customer.
Boards could be depopulated to reduce cost for customers who do not need wireless
capabilities. For other customers, implementing this could open up whole new
possibilities

for
applic
ations of our device.



13

Verizon
,

2G Modem
,

and

Micro
processor

Since we are going for a low cost product, this will best meet that requirement. The Huawei
MC323 can be found for
less than $100

online. A microproces
sor able to handle the
sensors and

data transmission
commands (
such as the
PIC24FJ64GA004), will be less than $10 each. The
microprocessor will not be under heavy load, since we will only sample at a low frequency (such
as once per minute or hour). The microprocessor will also not be heavi
ly taxed by the cellular
commands, as the modem will take most of the heavy lifting away from the microprocessor.

This option is much cheaper than integrated solutions with a modem and microprocessor on
one chip. These devices have many more features than
we require, and would be a waste.

Verizon was chosen for a multitude of reasons. First, they had a very helpful and informative
session with us to determine our options, unlike sprint. Second, they offer a trial period so we
can test our device on their ne
twork, as long as we pick an approved modem. Third, once we
finish our trial period, the data plans are at a reasonable cost.

The coverage of Verizon’s
network in the US is also superior to
other carriers.

Amazon EC2

Amazon EC2 was a simple choice here. It

is low cost (free) for devices that do not require large
amounts of computations. Second, it has static IP addresses and TCP/IP socket capabilities. This
will allow us to easily set up communications with the modem and the cloud.














14

Budget Estimat
e Per Unit

Item

Quantity

Expected Cost

Total Cost

PCB

1

$50.00

$50.00

Huawei MC323

1

$100.00

$100.00

PIC24FJ64GA004

1

$
4.02

$
4.02

RS485
Transceiver

(SN65HVD485EDR)

2

$2.01

$4.02

Antenna

1

$7.00

$7.00

Xbee

2

$20.00

$40.00

Sensor PCB

2

$0.00

$0.00

Sensor Microprocessor

2

$2.00

$4.00

RJ 11 Connectors, wire

1

$7.00

$7.00

Voltage Regulators,
Capacitors, resistors
, other
miscellaneous
components

1

$20
.00

$
20
.00

Batteries

10

$.50

$
5.00

Total

N/A

$21
2
.5
3

$241
.04










15

Total Expected Cost

Item

Quantity

Expected Cost

Total Cost

Full Units

2


$
241
.04

$4
82
.08


Data Costs
/Month/Line

6


$9.00

$
54
.00

Amazon EC2 Access

1

$0.00

$0.00

Breakout Board for Cell
Modem

1

$50

$50

Total

N/A



$586.08



Requested Budget

$586.08