Final+Project+Design+Process

=Project Title - Fridge Alert=

1. Further define and modify the requirements and specifications. 2. Perform different designs > a) Understanding the operation of switches. > b) Look up datasheet for power dissipation of each component (such as the IR emitter and sensor) in order to achieve the minimum overall power dissipation of the final circuit. 3. Evaluate different alternative designs for power dissipation and costs (Simulation). 4. Simulation and further evaluation. 5. Prototyping a design and test.



__Design Priority (written on May 14, 2009):__
1. User Safety 2. Power dissipation 3. Cost 4. Ease of use 5. Size



__Project Needs and Requirement (written on May 14, 2009):__
1. Modify the design idea of refrigerator alarm into a more user-friendly, sustainable product. 2. Foster sustainability - create a circuit with low power dissipation. 3. User-Friendly - create a product that is safe and easy to use, also small in size (wire space, length). 4. The product should act as an alarm (loud enough, proper durations) when the refrigerator door remains open for too long. 5. Low voltage, DC, operation. Do not interface with refrigerator (high voltage) circuit.

__More Specific Requirement (written on May 19, 2009):__
1. Alert users when the refrigerator door remains open for more than 20 seconds (using sound as the mean). 2. No interface with the refrigerator 120V circuit (using DC battery as the mean). 3. Use less power than the original design. 4. Proper Operation inside the refrigerator (maybe the freezer).



__Specification and Constraints (written on May 14, 2009):__
1. Turn on the alarm when the refrigerator door remains open for longer than 20 seconds, then, the alarm would sound for 20 seconds and off for 20 seconds. The cycle repeats until the refrigerator door close properly. 2. Low power dissipation (<5W) - proper for DC battery operation. 3. Minimum space requirement (less than a typical refrigerator magnet, ~3X5). 4. Low cost (< $5.00 for the prototype).

__More thoughtful Specification (written on May 19, 2009):__
1. Sound level of the alarm is between 70dB and 80dB. (http://www.eie.fceia.unr.edu.ar/~acustica/comite/soundlev.htm) 2. DC battery operation (between 3-10V). 3. Minimum space requirement (3 X 5 X 0.5'') 4. Wire Length (1 feet max if wire is used) 5. Cost ($4.00 for the prototype, not including the cost of batteries)


 * Design Review I PowerPoint (Click the following link to download the Design Review I PowerPoint):** [|Design Review I PowerPoint]


 * Design Review II PowerPoint (Click the following link to download the Design Review II PowerPoint):** [|Design Review II PowerPoint]