The Design Process Abstraction & Synthesis Part I

1. The Design ProcessAbstraction & SynthesisPart I by Prof. Bitar

2. Needs Assessment & Problem Formulation Homework #1 Need / Idea Perform Market Research HW#1 Needs Assessment & Problem Formulation Customer Requirements Brainstorm / Perform Technical Research Product Specification

3. Abstraction & SynthesisHomework #2 Research Prior Art Brainstorm Possible Solutions HW#2 Abstraction & Synthesis Perform Value Analysis Viable Options Apply Constraints Preferred Solution

4. Example Design Problem • We like to have candles in the windows of our house, especially around the Holidays. • The candles we currently have are plug-in, with long cords. • Some are turned on manually, while others have a sensor to automatically turn on, when it gets dark outside. • We have 12 windows with candles.

5. …and everything was fine until …?

6. Romeo ! (alias: Candle Kitty)

7. “The Masked Marauder” • Romeo has a bad habit of going from window to window, knocking down candles, breaking bulbs and getting tangled in cords… • My solution? • Not acceptable  • OK, I need your help…

8. The Customer Requirements • Explicit • Cat Safe • Look Nice • Different Colors • Automatic • Implicit • Low Cost • Reliable / Durable • Low Maintenance

9. Formal Brainstorming Session“The Idea Trigger Method” • Phase 1: Idea Generation Phase • Phase 2: Idea Trigger Phase • Phase 3: Compilation Phase

10. Brainstorming Session“The Rules” • No Holding Back • No Boundaries • No Criticizing • No Dismissing • No Limits • No Restrictions

11. Phase 1: Idea Generation • Take a few minutes to write down (list) your ideas on a piece of paper. • Identify possible solutions. • Identify possible features that the candles should have. • Identify as many areas of concern as you can think of. • Wild and crazy ideas are OK!

12. Phase 2: Idea Triggering • Now, as ideas are shared, eliminate duplicates from your list. • If you think of anything else, write it down on ANOTHER sheet of paper. • These are the new ideas triggered from the previous ones. • This process can be repeated as often as necessary until all ideas are exhausted.

13. Phase 3: Compilation • Compile a list of all the ideas and begin to discuss the feasibility of each. • Identify key areas of concern. • Identify practical solutions. • Identify a set of product requirements.

14. A Possible List of Customer Requirements • Safety / Durability • Heavy Base • Unbreakable Bulb or LED • Secure to Window Sill, Sash or Window Pane • No Cords • Low Voltage • Aesthetics • Traditional Look • Interchangeable Color Bulbs or LEDs • Flickering Option • Low Operating Cost • Long Battery Life (Efficient) • Rechargeable • Solar Rechargeable • Photo Sensor or Timer

15. Researching Existing Products“The Prior Art” • http://www.lightsforalloccasions.com/ • http://www.sillites.com/photos.php • http://www.qvc.com • http://www.uspto.gov/ • Solar Powered Electric Candle

16. More Prior Art - Dissected

17. Possible System Block Diagram Photo Sensor Solar Cell Charge Controller Rechargeable Battery Drive Circuit LED Mode Selection Flickering Control

18. Technical Research Areas Solar Cells – Availability, cost, size, shape, output voltage, output current, silicon types, spectrum sensitivity. Charge Controllers – Voltage Regulation, Current Regulation, etc. Rechargeable Batteries – NiCad, NiMH, Other?, Overcharging & Under-voltage Concerns, etc. Drive Circuits– Transistor, Voltage Regulator, DC/DC Boost Converters, Charge Pumps, etc. LED’s – Colors, Voltage Levels, Current Requirements, Intensities, Illumination Angles, etc. Photo Sensors – Types, Interface Requirements Analog and/or Digital Processing – op amps, digital logic chips, microcontrollers

19. A Practical Approach • Start with the Distributors • www.digikey.com • www.mouser.com • Then the MFG’s Data Sheet • Repeat this process for each block or component in your diagram. • Begin to consider the interfaces between blocks.

20. Picking one aspect: LED’sQuestions to Answer • What LED’s are available? • Colors? Sizes? Shapes? • What are the key LED specifications? • What is the proper way to power an LED? • How much do they cost? • What companies manufacture LED’s? • What companies distribute LED’s? • How much energy is required for this application?

21. Colors • Infrared • Red • Orange • Yellow • Green • Blue • Violet • Ultraviolet • White Voltages Ranging from 1.6V to 3.2V depending on color (assuming a constant current of 20mA)

22. Agilent White LED Spec. Sheet

23. LED Specifications – Curves !Max. Forward Current vs. Voltage Check: 20mA @ 3.2V (Typical)

24. LED Specifications – Curves !Relative Luminous Intensity Wavelength (nm)

25. LED Specifications – Curves !Spatial Radiation Pattern Check Viewing Angle !!

26. LED is ChosenBlock Diagram is Modified Photo Sensor White LED 3.2V @ 20mA (worst case) Solar Cell Charge Controller Rechargeable Battery Efficient Drive Circuit Mode Selection Flickering Control

27. Here’s another… What about the Battery? • (To Be Continued…) • In the meantime, you come up with a list of questions.