Design Lab 5: Blinking LED Design

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Design Lab 5 Blinking LED Design

• Eric Hanken, Prisco Castoria, Austin Kellerman

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Specifications and Constraints

• The system shall use LEDs, including a blinking
  LED.
• The blinking light system shall be highly visible
• The system shall use 4 AA batteries (6V).
• The system shall last a long time
• The blinking lights shall be attached to a
  headband, armband, baseball cap, or hair scrunchy.

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Available Materials

• 4 AA batteries
• Plastic battery holder
• 1 blinking LED
• 2 non-blinking LEDs
• Wire
• Wire cutters
• Electrical tape
• Switch
• Headband, armband, baseball cap, or hair scrunchy.

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How Series and Parallel Circuits Work

• A series circuit will make all LEDs blink, but
  the light output is decreased due to voltage drop
  across the circuit .
• A parallel circuit will make only the LEDs
  blink, but the light output is increased more
  than the series circuit.

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Why we Choose a Hat

• It is the easiest to integrate the materials
  LEDs, battery pack etc.
• The hat already has air holes so we can simply
  put the LEDs through them.
• The battery pack can be hidden nicely under the
  lid of the hat.

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Testing

• To test which LED offered the most light output,
  we connected each one directly to the battery
  pack. We had a member of the team go on the
  other side of the room to judge the relative
  light output of each LED.
• To test what caught a persons eye better,
  blinking or brightness, we did the same test but
  wired each LED in series with the blinking LED.

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Alternative Designs

• Our other designs consisted of placing all three
  LEDs in the rear of the hat. This would offer
  maximum visibility from the back, where it is
  need most.
• Another design would be to place the LEDs around
  the hat but have them wired in parallel so they
  would be as bright as possible.

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Final Prototype

• The final prototype consists of LEDs placed in
  the air holes around the hat. They are wired in
  series to allow all the LEDs to blink. The
  placement of the lights insures that they can be
  seen from all angles.
• The prototype is a mix of our two other designs.
  Series wiring from the first design, and LED
  placement from the second design.