Cell Extender By Faisal Al-Ali Hisham Dhaifullah Advisor: Prof. Miller

1. Cell Extender By Faisal Al-Ali Hisham Dhaifullah Advisor: Prof. Miller University of Michigan-Dearborn College of Engineering and Computer Science Fall 2009

2. Cell Extender Cell Extender • The Cell Extender is a one of a kind medium that links your cell phone to you home phone (touch-tone phone). • Using existing landline phone wires embedded in your home, the Cell Extender literally has you covered from anywhere in your home. • All you need is a touch-tone phone and access to a phone jack. University of Michigan-Dearborn College of Engineering and Computer Science Fall 2009

3. Mandatory Requirements • Pair and Bond Bluetooth compatible cell phone with • embedded Bluetooth chipset on Cell Extender. • Receive cell phone data over the air through Bluetooth and transmit that data over twisted pair phone line to touch-tone phone. • Alert user of an incoming call on touch-tone phone. • Answer incoming call and establish two-way communication • with cell phone. • Hang-up call from touch-tone phone and terminate • communication on cell phone end. University of Michigan-Dearborn College of Engineering and Computer Science Fall 2009

4. Revisions Over the course of the semester, several critical revisions were made to ensure the feasibility of the project: HIGH POWER ISOLATION The greatest obstacle to the realization of the project was to ensure the safety of embedded electronics and, more importantly, the safety of the user from the high power voltages involved in the design. The key components that address this issue is the use of Solid State Relays (SSR’s). University of Michigan-Dearborn College of Engineering and Computer Science Fall 2009

5. Revisions 2 Solid State Relays (SSR’s) • SSR’s use low current control of high current loads which are isolated optically or with transformers (National Instruments 2009). • By decoupling the circuit board from the main power supply, you provide a safe barrier from threats such as lightning, EMI pulses, ESD, and switching of reactive loads (Standler R. B., 1989). University of Michigan-Dearborn College of Engineering and Computer Science Fall 2009

6. Revisions 3 Optical SSR’s • Optical SSR’s use light to couple input and output ports. Insulation between the light source and the detector (transistor) can withstand steady-state voltage of several kilovolts (Standler R. B., 1989). Relay (SSR): Light from the encapsulated LED actuates the photo-sensitive MOSFET and allows current to flow through it (National Semiconductor, 2009). University of Michigan-Dearborn College of Engineering and Computer Science Fall 2009

7. Revisions 4 Isolation Transformer • An isolation transformer does not have a conductive path between input and output ports and transmits energy via a magnetic field (Standler R. B., 1989). This is the first line of protection to the end user. (Hammond Manufacturing; 115 V AC to 90 -130 V AC tapped) University of Michigan-Dearborn College of Engineering and Computer Science Fall 2009

8. Revisions 5 DIRECT USE OF MAIN POWER SUPPLY • For simplicity of design and at the suggestion of our senior design advisor, the main power supply will be directly used as the source of the AC wave generator with no need for any power inverters. This decision greatly reduces valuable prototyping PCB space, cost, and development time. PHONE LINE POWER FROM PIC16F690 • The PIC microcontroller will provide the DC voltage necessary to power-up the phone line for voice communication. It will be TTL output that is fed into a voltage regulator in a non-inverting configuration which will boost the voltage up to 12 volts with a current at one ampere. This is more than enough to power phone lines and telephones extending for several miles. Making DC line voltage software programmable adds better timing and coordination with other subsystems. University of Michigan-Dearborn College of Engineering and Computer Science Fall 2009

9. Inside the Cell Extender • The Cell Extender combines central telephone office electronics, home phone • electronics, and Bluetooth to provide a communication medium between your • cell phone and your home phone. • Your home will represent, in microcosm, your local telephone companies service to the community with the last link in the communication chain being Bluetooth wireless transmission. University of Michigan-Dearborn College of Engineering and Computer Science Fall2009

10. Block Diagram University of Michigan-Dearborn College of Engineering and Computer Science Fall2009

11. Loop Detection Network University of Michigan-Dearborn College of Engineering and Computer Science Fall2009

12. Telephone Ring Detection University of Michigan-Dearborn College of Engineering and Computer Science Fall2009

13. Phone Status Indicator University of Michigan-Dearborn College of Engineering and Computer Science Fall2009

14. Pulsed AC Wave Generator University of Michigan-Dearborn College of Engineering and Computer Science Fall2009

15. PIC 16F690 Interface University of Michigan-Dearborn College of Engineering and Computer Science Fall2009

16. Speech Network University of Michigan-Dearborn College of Engineering and Computer Science Fall2009

17. Speech Filter University of Michigan-Dearborn College of Engineering and Computer Science Fall2009

18. Transmission Amplifier University of Michigan-Dearborn College of Engineering and Computer Science Fall2009

19. Voltage Regulators University of Michigan-Dearborn College of Engineering and Computer Science Fall2009

20. Bluegiga Bluetooth Module University of Michigan-Dearborn College of Engineering and Computer Science Fall2009

21. Design Specifications • Pulsed AC Generator Input: 120 volt AC, 60 Hz main line voltage Output: 90 volt AC, 60 Hz • PIC16F690 Input: 5 volts regulated power. Voltage Supply: Provide 5 volt TTL power output to voltage regulators. Code Execution: Lift-up action (ring-up) Shall not be detected if the closure duration is less than 20 ms. Shall be detected if the closure duration is greater than 200 ms. Hang-up action Shall not be detected if the opening duration is less than 250 ms. Shall be detected if the opening duration is greater than 370 ms. University of Michigan-Dearborn College of Engineering and Computer Science Fall2009

22. Design Specifications continued • Speech Network Signal to Noise Ratio:Minimum of 40dB voice quality (Plain Old Telephone Standard-POTS). Filter: 300 Hz - 3 kHz. Voice transmission gain: 50 dB • WT-32 Bluegiga Bluetooth Module Performance Criteria: • Automatic connection request upon power-up • Connection stability of 8 hours or more. • Answer incoming cell phone call when touch-tone phone receiver is lifted up. • Terminate cell phone call when touch-tone phone receiver is hung-up. University of Michigan-Dearborn College of Engineering and Computer Science Fall2009

23. Design Specifications continued • Voltage regulators • Regulated steady-state output of 12 volts for phone line. • Regulated steady-state output of 15 volts for TL072 op amps, and 555 timer IC. • Regulated steady-state output of 3.3 volts for WT-32 Bluetooth module. • Regulated steady-state output of 3 volts for Phone Status Circuit. • Regulated steady-state output of 5 volts for PIC16F690. • Regulated steady-state output of 5 volts for photo-relays and photo-transistor. University of Michigan-Dearborn College of Engineering and Computer Science Fall2009

24. Questions ? University of Michigan-Dearborn College of Engineering and Computer Science Fall2009