1. Free Space Optical Communications Senior Design Project Fall 2011 TEAM AWESOME

2. OVERVIEW Project Requirements Key customer needs Metrics Concept Generation Concept Selection Transmitter Demonstration Action Items

3. PROJECT REQUIREMENTS Customer Needs Questions for the CustomerExpected ResponseInterpreted NeedsPriority What frustrates you the most about setting up a surround sound audio system? Wires, system is too hard to setup, unsightly, takes too long to setup Simple plug-n-play wireless setup 3 In what room and size of room would you want to set up this system? In a living room or a basement/rec room. Up to 20’ An operating range of at least 20’2 What price would you be willing to pay for this system? $50 per transmitter/receiver set Low Cost2 How important is it to have a wireless connection for your speakers? Depends on the ease of installation of other systems, but it is preferred Wireless is Preferred1 How high a quality does the sound need to be? Can’t tell the difference for the average ear, so high quality High quality sound3 How would you prefer to power this device? The option to do either batter-operated or plugged in. Low power consumption is a must Versatility in power options2

4. PROJECT REQUIREMENTS Metrics MetricUnitsMin/MaxIdeal Cost per unit $ /set < 75< =50 Wireless operating range feet > 20 40 Time to set-up minutes <205-10 Number of pages in operating manual pages < 105 Battery life hours >= 25 Amount of interference/audible errors per unit time #/minute <= 1<0.2 Size of product package ft 3 < 1< 0.5 Number of wires needed # <= 5<= 3

5. CONCEPT GENERATION System Block Diagram ADC Laser Driver Laser Power & Charging Light pulses Audio Signal DAC Receiver Photo Diode Power & Charging Transmitter Receiver

6. CONCEPT GENERATION Laser Driver Circuit Options Op Amp Single BJT Criteria Power Consumption Complexity of Design Reliability

7. CONCEPT GENERATION Receiver Circuit Options Op Amp Single BJT Resistor Criteria Power Consumption Complexity of Design Reliability

8. CONCEPT GENERATION Battery Charging Circuit Options Trickle Charger Quick Charger Criteria Charging Speed Complexity of Design Risk of Damaging Battery

9. CONCEPT SELECTION Laser Driver Circuit Concept Scoring Switch Selection Weighted Value Op AmpSingle BJT Score Weighted Score Weighted Power Consumption 5042008400 Complexity of Design 157105575 Reliability 3562105175 Total 100 515650

10. CONCEPT SELECTION Receiver Circuit Concept Scoring Switch Selection Weighted Value Op AmpSingle BJTResistor Score Weighted Score Weighted Score Weighted Power Consumption 4041608320280 Complexity of Design 10770550990 Reliability 50630052502100 Total 100 530620270

11. CONCEPT SELECTION Battery Charging Circuit Concept Scoring Switch Selection Weighted Value Trickle Charger Quick Charge Score Weighted Score Weighted Charging Speed 154608120 Complexity of Design 3582803105 Risk of Battery Damage 5094504200 Total 100 790425

12. TRANSMITTER DEMONSTRATION

13. ACTION ITEMS Complete Project Schedule Complete Working Receiver Integrate Receiver and Transmitter Complete Working Prototype