Component Breakdown
LEDS - We wanted the LEDs to be blue to best represent the Arc Reactor from movies. The voltage drop across blue LEDs is significantly greater than across LEDs with a longer wavelength. So we are looking at near a 3.3V drop from the LED.
SWITCH - To activate the circuit when the yo yo is spinning, we looked at a couple of different types of switches.
First, we looked at creating a mechanical system that would take advantage of the spinning motion of the yo yo to move a spring and close the circuit. A similar design was used in a Make magazine project. http://makezine.com/projects/led-yo-yo-side-caps/
Then, we looked at switches that are activated by motion.
Mercury Switches - would work, but are going out of style for safety concerns
Vibration Switches - also would work, but might be too sensitive - we don't want it lighting up if you're just carrying the yo yo in your pocket
Tilt Ball Switches - this is what we decided to try. When the yo yo spins, the internal ball will move and close the circuit, and the lights will go on.
BATTERY - We wanted something as small (and symmetrical) as possible. Watch batteries fit these requirements well. After diagramming and experiments, we decided to use 2 CR2012 watch batteries for each circuit.
Experimenting with LED, batteries, and math
After playing with different watch batteries, LEDs, and doing some circuit equations, we have determined that our circuit should work (in theory). Just waiting for the actual components to arrive to double check!
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| Comparing one LED powered by 6v, to 3 LEDs in parallel with 3V |
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| 3 LEDs in parallel with 6V |
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Physically planning circuit |
Playing with LED orientation
LEDs are brightest viewed from the top, but for assembly ease we wanted the LEDs to be on their side in the LED holder. At 3V powering the circuit, the side view of the LED was very disappointing. But at 6V, the glow was much better.
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| With 3V |
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| With 6V |
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