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Group Design Project

Design requirements



Characteristics of design requirements





Types of design requirements





Documenting design requirements


In a report, the design requirements are written as a numbered list ordered by importance:

The value of your design is in the selection and prioritization of items on the list. Selection of requirements is more important than length or quantity of list. Do not include marketing information or a sales pitch.



Bad example of design requirements for a bicycle:

  1. Easy to install
  2. Allows replacement of worn parts
  3. Allows easy traversal of slow, difficult terrain
  4. Provides stiff mounting points for the brakes
  5. Reduces vibrations to the hands
  6. Allows sensitivity adjustments
  7. Easy access for maintenance
  8. Can be maintained with readily available tools
  9. Preserves the steering characteristics of the bike
  10. Remains rigid during cornering
  11. Lightweight
  12. Affordable
  13. Not easily contaminated by water and dirt
  14. Lasts a long time
  15. Safe in a crash



Better example of design requirements for a supersonic passenger aircraft:

  1. Carry payload of 300 passengers at 175 lbs and 40lbs of baggage each
  2. Operate using a crew of 2 pilots and 10 flight attendants at 175 lbs and 30lbs of baggage each
  3. Operate within a range of 5,500 nm followed by a 30 minutes loiter
  4. Cruising speed at Mach 2.5 at 65,000 ft
  5. Outbound and inbound subsonic cruise legs of Mach 0.95 at 45,000 ft
  6. Take-off and land on field length of 12,000 ft
  7. Use JP-4 fuel
  8. Satisfy FAR 25 and FAR 36 certifications



Bad example of design requirements for a portable digital instrument to use at hospitals:

  1. Interface with hub, which connects to laptop via analog signal
  2. Should not introduce cross contamination between patients
  3. Handheld device
  4. Sturdy and durable
  5. Calibrated according to international standards





Better example of design requirements for a portable digital instrument to use at hospitals:

  1. Device must run at a maximum of 3.3V per thermometer. It must require less than 500 mA of current.
  2. The device must cause no harm to the patient from the circuitry or sensory interface.
  3. It must be within 1 degrees celsius of the true temperature. The device must be accurate within 32 to 42 degrees Celsius.
  4. The device must last for a minimum of 5 years under normal operating conditions.
  5. The device must be able to withstand humid and hot conditions (up to 47 degrees Celsius) as well as any transportation.
  6. The device must be able to function properly in high heat.
  7. It must be easy to use for untrained persons with minimal maintenance.
  8. The handheld structure must be comfortable for both the patient and the operator.
  9. The device must be small enough to be handheld.
  10. The device must be lighter than 0.4 kg
  11. The device must use low cost materials, excluding latex, which can be easily sterilized in a 10% bleach solution.