1. A Cell Phone-Based Remote Home Control System
Adam Mohling – CprE
Issa Drame – EE
Chau Nguyen – EE
Faculty Advisor:
Ahmed E. Kamal, Professor
Client: ECpE Department
April 15, 2019
SDMay6-13

2. 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
April 15, 2019
SDMay6-13

3. 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…
April 15, 2019
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4. Problem Statement
Design a system that allows users, upon authentication, to remotely control and monitor multiple home appliances using a cell phone-based interface.
April 15, 2019
SDMay6-13

5. 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
April 15, 2019
SDMay6-13

6. 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
April 15, 2019
SDMay6-13

7. 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
April 15, 2019
SDMay6-13

8. 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…
April 15, 2019
SDMay6-13

9. Assumptions Dry environment (indoors)
Only electrical devices shall be controlled by the system
A cellular signal shall be accessible in the cellular module’s location
Users are familiar with text messaging
The individual installing the unit shall have an electronics background
April 15, 2019
SDMay6-13

10. 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
April 15, 2019
SDMay6-13

11. End Product and Other Deliverables
System Components:
Cellular Phone
Cellular Module
Microcontroller
Software
Controlled Devices
Other:
Documentation
Project poster
April 15, 2019
SDMay6-13

12. 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
April 15, 2019
SDMay6-13

13. System Components Cellular Phone Cellular Module Microcontroller
Software
Controlled Devices
April 15, 2019
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14. Project in Action – Entire System
Thermostat
Fan
Lamp
Controlled Devices…
April 15, 2019
SDMay6-13

15. 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
April 15, 2019
SDMay6-13

16. Approaches Considered – Cellular Modules
EE54 edge
GM47/48
GM28/29
Module Selected: GM28
Reasons for Selection:
RS232 DB9 connector
No kit necessary (~$600)
Located coding examples
April 15, 2019
SDMay6-13

17. Approaches Considered – Microcontrollers
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
April 15, 2019
SDMay6-13

18. 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 STK300’s 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
April 15, 2019
SDMay6-13

19. Controlled Devices
The following devices have been selected to be controlled by the team for proof of concept:
Fan
Light
Digital thermostat
April 15, 2019
SDMay6-13

20. Design Activity – Fan Circuit
Controlled Device Considered
Fan Operations:
4 position switch
3 windings on one core
Switch selects either a winding or off position
Implemented through relays
3 control relays is in parallel with switch
Remote/Manual select relay
April 15, 2019
SDMay6-13

21. Design Constraints – Thermostat
Setting based on simulating up/down push-button inputs
Current temperature determined by decoding LCD data input
How to interface the digital thermostat with microcontroller
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22. Design Constraints – Decoded LCD Display
Green/Gray
Yellow/Blue
Black/Blue
White/Green
Blk/Green
Brown/Grey
Blk/Gold
White/Blue
Blue/Grey
1….....2…….3…4……5…….6
Scan direction
April 15, 2019
SDMay6-13

23. 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
April 15, 2019
SDMay6-13

24. 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
April 15, 2019
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25. Reporting Schedule
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26. Development Schedule
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27. Personnel Resources
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28. Financial Resources
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29. 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
April 15, 2019
SDMay6-13

30. 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
April 15, 2019
SDMay6-13

31. 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
April 15, 2019
SDMay6-13

32. 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
April 15, 2019
SDMay6-13

33. 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
April 15, 2019
SDMay6-13

34. Acknowledgements Special thanks to the following:
Sony Ericsson for providing the team’s GM28 cellular module
Kanda for providing the team’s STK300 microcontroller kit
Professor Kamal for his continued support to the team
April 15, 2019
SDMay6-13

35. 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.
April 15, 2019
SDMay6-13

36. Questions? GM28 STK300 Controlled Devices… Text Messages
Lamp
GM28
Any device with an electrical interface
Fan
STK300
Controlled Devices…
Text Messages
Thermostat
April 15, 2019
SDMay6-13