A Cell Phone-Based Remote Home Control System

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A Cell Phone-Based Remote Home Control System
Chau Nguyen EEchayman_at_iastate.edu
Adam Mohling CprEmohbandy_at_iastate.edu
Issa Drame EEissad_at_iastate.edu
Faculty Advisor Ahmed E. Kamal,
Professorkamal_at_iastate.edu
Client ECpE Department www.ece.iastate.edu
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Presentation Outline

• Problem statement
• Operating environment
• Intended users/uses
• Assumptions limitations
• End product other deliverables
• Resources schedules
• Commercialization
• Risks risk management
• Lessons learned
• Closing summary evaluation

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List of Definitions

• GSM Global System for Mobile communication
• SMS Short Message Service
• MSDNAA Microsoft Developers Network Academic
  Alliance
• M2M Mobile to Mobile / Machine to Machine

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Problem Statement

• Design a system that allows users, upon
  authentication, to remotely control and monitor
  multiple home appliances using a cell phone-based
  interface.

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General Approach (Proof of Concept)

• The system will be microcontroller based and will
  do the following
• Have connectivity to a cellular network
• Accept commands from a cell phone
• Be able to decode (and issue) user commands
• Have the ability to interface with electrical
  devices

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Research Activities

• The team researched the various components of the
  system, including the following
• Cellular modules
• Microcontroller
• Programming languages
• Interfacing with potential controlled devices
• Miscellaneous circuit components

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Operating Environment

• Two separate units
• Cellular module and control unit will be located
  indoors
• Cell phone from which the user will interact with
  the system

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Intended User(s) and Use(s)

• Any group or individual who wish to have the
  ability to control or check the status of an
  electrical device from a remote location.
• Feasible appliances
• Lights, thermostat, security system, garage door,
  etc

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Assumptions

• Dry environment (indoors)
• Only electrical devices shall be controlled by
  the system
• A cellular signal shall be accessible in the
  cellular modules location
• Users are familiar with text messaging
• The individual installing the unit shall have an
  electronics background

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Limitations

• A 120V power source will be available
• Communication can only be established through SMS
  messaging (text message)
• Only electrically operable devices can be
  controlled by the system
• System will not operate in an extreme climate
• This system will not perform in real time

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End Product and Other Deliverables

• System Components
• Cellular Phone
• Cellular Module
• Microcontroller
• Software
• Controlled Devices
• Other
• Documentation
• Project poster

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Research Activities

• The team researched the various components of the
  system, including the following
• Cellular modules
• GSM network communication
• Microcontroller
• Programming languages
• SMS messaging format
• Modem AT commands
• Interfacing with potential controlled devices
• Miscellaneous circuit components designs

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System Components

• Cellular Phone
• Cellular Module
• Microcontroller
• Software
• Controlled Devices

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Project in Action Entire System
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Approaches Considered User Communication

• Tone Decoding (DTMF)
• Text Messaging (SMS)
• Technologies Selected Text Message
• Reasons for Selection
• Allows user to verify and edit the message before
  sending to ensure the command issued is the
  command requested
• Data is transmitted in binary, requires less
  hardware to manipulate (as opposed to DTMF)
• Most commonly used in M2M technology

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Approaches Considered Cellular Modules

• Considered
• EE54 edge
• GM47/48
• GM28/29
• Module Selected GM28
• Reasons for Selection
• RS232 DB9 connector
• No kit necessary (600)
• Located coding examples

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Approaches Considered Microcontrollers

• Considered
• STK200 Features (66)
• STK300 Features (85)
• Freescale (Motorola) MC68HC11E9 Starter Kit
  Features (99)
• Philips 51 Plus Starter Kit Features (95)
• Microcontroller Selected STK300 Starter Kit
• Reasons for Selection
• Most economical (85)
• Largest amount of memory (128KB)
• RS232 connectivity
• Application Builder, AVR Studio, programmable in
  C Language

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Approaches Considered Programming Languages

• All the software developed for this project will
  be loaded into the memory of the STK300
  microcontroller.
• The language must be supported by the STK300s
  compiler
• The STK300 compiler supports C and Assembly
• Java and C considered because code can be
  converted to C
• Assembly C C Java
• Selected Programming Language C Programming
  Language
• Reasons for Selection
• Vast amount of online resources
• Ease of development
• Team members have experience coding C

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Controlled Devices

• The following devices have been selected to be
  controlled by the team for proof of concept
• Fan
• Light
• Digital thermostat

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Design Activity Fan Circuit
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Design Constraints Thermostat

• Setting based on simulating
  up/down push-button inputs
• Current temperature determined
  by decoding LCD data input

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Design Constraints Decoded LCD Display
Green/Gray
Yellow/Blue
Black/Blue
White/Green
Brown/Grey
Blk/Green
White/Blue
Blk/Gold
Blue/Grey
1.....2.345.6
Scan direction
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Implementation Activity

• The serial I/O between the STK and GM28 were
  conflicting.
• Status detection circuit
• Initially voltage detector
• Redesigned into current detector
• All other implementation activities went
  according to plan

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Testing and Modification

• GM28
• Testing was performed using the Windows
  HyperTerminal application
• STK300
• Simple programs were developed to manipulate the
  I/O pins and voltages were measured for
  correctness
• Serial communication was tested using the Windows
  HyperTerminal application
• Circuits
• Circuits were developed using PSpice and then
  implemented in the lab
• Unit Testing
• Each circuit component will be tested for proper
  voltage levels prior to connectivity to other
  components
• Other
• Subjects from the general public were selected to
  test the end product

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Reporting Schedule
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Development Schedule
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Personnel Resources
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Financial Resources
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Project Evaluation

• Milestone Outcome
• GM28 STK300 communication
• Text message retrieval and parsing Fully met
• Text message sending Not met
• STK300 control devices
• Status detection circuit design Fully met
• Status detection circuit implementation Partially
  met
• Control circuits Fully met
• LCD decode matrix Partially met
• Thermostat control Partially met
• Software
• User authentication password change Fully met
• Fan Fully met
• Light Fully met
• Thermostat Fully met
• Initialization of serial and I/O ports Fully met

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Commercialization

• Modifications to control unit
• Create new software adapted for given product
• Implement a commercially available standard bus
• Modifications to existing commercial product
• Hardware interface installation
• Send installation team onsite to install product
• Not feasible for small-scale development in a
  single user household

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Recommendations for Additional Work

• Obtain permanent service from a cellular provider
• Additional system implementation
• Hardware
• Status detection
• LCD matrix decoding
• Software
• Sending of messages via GM28
• Status detection software
• Thermostat LCD software
• Continued system testing

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Risk Management

• The team planned for the following risks
• Loss of a team member
• Two team members per task
• Data loss
• Multiple storage locations
• Part orders
• Alternative distributors
• Destruction or loss of parts
• Reorder parts as quickly as possible

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Lessons Learned

• What went well
• Team organization
• Time management
• Spread of effort
• Equal contribution among team members
• What did not go well
• Delay of delivery of system components
• Serial communication
• Status detection circuit
• What technical knowledge was gained
• AT commands
• Digital logic
• Microcontroller knowledge
• Use of online resource such as forums provided a
  great deal of knowledge to the team

• What non-technical knowledge was gained
• Time management
• Realization of efforts required for documentation
• Working on a professional project
• What would be done differently if the project was
  to be done again
• Follow the schedule more closely
• Order parts sooner
• Work ahead

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Acknowledgements

• Special thanks to the following
• Sony Ericsson for providing the teams GM28
  cellular module
• Kanda for providing the teams STK300
  microcontroller kit
• Professor Kamal for his continued support to the
  team

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Closing Summary

• Although the team encountered many obstacles
  during the development of this project, the
  realization that devices can be controlled from a
  remote location via a cell phone interface makes
  this proof-of-concept project a success. All team
  members contributed equally to progress this
  project as far as it did and all team members
  were satisfied with the end result.

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Questions?
GM28
Any device with an electrical interface
STK300
Controlled Devices
Text Messages