Senior Design Presentation

pleasanthopebrothersElectronics - Devices

Nov 2, 2013 (3 years and 7 months ago)

254 views

Wireless Domotica

Group
-
14 Members

Vishal Sethi

Jandeep Bawa

Javier Otin

Hardik Desai


Sumit Ghosh: Faculty Advisor

Fred Bruno: Senior Design Instructor

Abstract


Remotely access and control your home
appliances using a mobile phone


Project divided into four modules:


Module I: Programming wireless devices using
WAP and J2ME


Module II: Interconnection between wireless
devices and Server


Module III: Interconnection between the micro
controller and server


Module IV: Interaction between the
microcontroller and various devices using X
-
10
protocols

System Overview

Hardware Deployment


Devices and protocols involved


Micro
-
controller


Relays


X
-
10 protocols



Hardware Deployment


Microcontroller


Communicates with other
devices using a X
-
10
protocol and a relay circuit


Features of the controller


A 8051 derivative with a
8 input, 12 bit A/D
converter, 2 output 12 bit
D/A converter, 4
-
16 bit
counter/timers


Has 32K of program
FLASH memory and 2304
bytes of SRAM.

Hardware Deployment


Generate it's own clock,
at 2, 4, 8, or 16 MHz


Has a JTAG interface
that makes possible
non
-
intrusive in
-
circuit
software debugging


Relay circuit


Must be capable of
turning on or off an
appliance.


Transistors in the circuit
will act as an amplifier


Resistors before
transistor will control
the current

Hardware Deployment


X
-
10 protocol overview:


Communications "language" that allows
compatible products to talk to each other via the
existing power line.


Transmitters send a coded low voltage signal
superimposed over the 110VAC current


Receivers respond only when it sees a signal that
has its address


Up to 256 different addresses are available
depending on the characteristics of device

Hardware Deployment


Commands represented
on the power line by
bursts of the 120 KHz
signal, which form data
bits


Collection of bits forms
32 commands called key
codes


Half of these represent
unit addresses and the
remaining half represent
commands (on, off, etc.)

Hardware Deployment


House code precedes the
key code, which makes 9
bits (4 house code, 5 key
codes) plus a start
sequence of 2 bits for a
total of 11 bits


As we require 2 way
communication, we are
using a two way X10
device


Can use all the 256
addresses


Can report its status to
micro
-
controller

TW523 Two Way interface module


Software Implementation


Why new protocols for wireless?


Limited battery life in wireless devices


Less powerful CPU, less memory, smaller
display…


Used in more dynamic way than desktops


There can be no installation scripts,
complicated menu structures etc.

WAP


The new de
-
facto


It bridges the gap
between mobile
world and internet.


Access same wealth
of information from
a pocket sized
device as from the
desktop

WAP Programming Model


Based on existing www programming model.


Uses Wireless Markup Language (WML) for
the client device.

WAP Protocol Stack


WAE


content encoders
and decoders


WSP


session layer for
efficient exchange of data


WTP
-

transaction
support, adds relaibility


WTLS


Security Layer


WDP


Transport Layer

What’s new in WAP?


Uses “push” functionality.


Optimized for low bandwidth, high
latency and less connection stability.


Binary transmission for greater
compression of data


Scalable layered architecture


layers
are independent of each other


Pro’s of WAP


Open standard, vendor independent


Network
-
standard independent


Transport mechanism
-

optimized for wireless
data bearers


Application runs from the server, enabling
fast service creation and introduction, as
opposed to embedded software


Largest global penetration to end users


Provides light
-
weight scripting language


Con’s of WAP


Nominal graphics, no color


Existing HTML sites must be rewritten,
code optimized per device


Security holes in WAP when data is
handed over from WTLS (wireless) to
SSL (internet)


Gateway required for transcoding
between HTML and WML


J2ME
-

Java 2 Micro Edition


Dynamic delivery of
services


Cross
-

platform
compatibility


Enhanced user
experience
-

GUI
Interface


Disconnected access
and Synchronization
Security

Connected Limited Device
Configuration (CLDC)


Targeted at devices with:


160KB to 512KB total memory available for

Java™ technology


Limited power (often battery)


Limited and intermittent network connectivity


Extremely constrained UIs, small screens




CLDC 1.0 specification available for free
download now

Mobile Information Device
Profile (MIDP)


Targets mobile two
-

way communication
devices implementing J2ME CLDC



Specifies display and user input, data storage
in the device, and HTTP
-
based networking



HTTP
-

based networking using CLDC Generic
Connection framework



MIDP 1.0 spec and implementation available
for download now

J2ME Today

MIDlets can be downloaded wirelessly or using a cable

Wireless Carriers (U.S.):

Nextel

Sprint

Manufacturers

Motorola Nokia

Siemens

Pro’s of J2ME


Supports https protocol for e2e security


No gateways (lower costs, simpler
testing)


MIDlet GUI offers uniform behavior
across devices


Adopted by handset manufacturers and
carriers globally for 3G

Con’s of J2ME


Installation Overhead
-

MIDlet must be
installed in device


Security


Handset maker has option
not to do SSL


Existing HTML sites must be rewritten


Nominal penetration in the market


User Interface


User


friendly interface


Similar functions for both
WAP and J2ME


Mobile phone will
enable user


Know status of his / her
home


Control any device
connected to the power
line

User Authentication

Home Status

Home Appliances

Gantt Chart

Gantt Chart

Future Enhancement:

Sending Pictures to handsets


Difficulties:


Handsets with color LCD screen
not available in the U.S.


Emulators are still in beta phase


Needs high bandwidth



Benefits:


This would be the killer app, would
make our project very appealing to
security firms and 3G telecom
companies


Conclusion


Fully functional prototype will be
implemented by end of next semester


If implemented commercially will
benefit telecommunications as well as
security industries.


Please free to ask any questions.