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Guy |
SERVICES: |
ENGINEERING PROTOTYPES |
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| PRODUCTS: |
LEVITATION KIT |
ELECTRONIC ARTWORK |
THERMAL WINDOWS |
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| SOLAR INFO: |
SUSTAINABLE LIVING |
SOLAR HEATING | SOLAR HOT WATER | SOLAR MOWER | ||
| RESOURCES: | ABOUT ME | IN THE MEDIA |
BUILDING A CANOE |
LINKS |
Guy
Marsden
Artwork
Engineering
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| Three people pedal bicycles on trainer stands to generate electricity, lighting up a tower of multicolored lights and gleaming reused bike wheels. The faster they pedal the higher the lights go. Working together they light up all ten levels. Surrounding the tower is a wattometer that relates how much wattage is being generated to how much wattage different household tasks consume. Some household usages are way off the scale. Questions about the cycles our energy use sets off around energy procurement and production, pollution and human rights will be raised. |
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Rebecca contacted me early in the summer with the idea for a bicycle
generator that could tangibly show how much energy is being generated by
lighting up a column consisting of hundreds of LEDs to light acrylic rods in
bicycle wheels that light higher as more power is generated. My job was to convert 3 bike trainer stands so they could each generate up to 50 Watts when pedaled at full speed, for a combined total of 150 Watts. Then I built electronic controls to operate the lights. |
 Since
I already had a trainer here that my wife no longer used, I began by adapting a
motor onto it that when driven would generate 12 Volts at up to 4.5 Amps.
This required some careful machining and custom brackets to mount the motor.
(DC motors when turned produce electricity, so the motor's power rating of 12V 4.5Amp is also the amount of power that it can generate.) |
 I
had to work up quite a sweat on many occasions to test the generator with a 50
Watt light bulb. This is not a standard 120 Volt lamp, but a 12 Volt one
as used in RVs and vehicles, they are available in hardware stores and RV/marine
supply places.I used meters to test the voltage and current and was able to clearly see the voltage increase as I pedaled faster as the lamp also ran brighter and brighter. Rebecca sent me 2 more trainers that I also converted and then sent all 3 to her. |
 The
next part of the job was to build electronics that would light up 10 circuits of
LED lights in sequence in direct proportion to the voltage being generated.
I was very concerned that the generators could be pedaled fast enough to
generate too much voltage that could blow out the electronics. To limit
the voltage to a safe range, I added a circuit that kicks in several additional
lamps if the voltage goes over 12 Volts. This makes it much harder to
pedal the generators and forces people to slow down and limit the generated
voltage.The control circuit uses a bar graph chip that would normally be used to light up the volume level indicator in a mixer or old style stereo where rows of LEDs light up to show the volume. I simply amped up the power of this chip with high power MOSFET drivers and voltage regulators to protect the LEDs. I also worried that accidental shorts in the LED wiring could cause damage to the controls so I built automatic fuses into each circuit that would re-set once the short was removed. Rebecca did an amazing job of wiring up hundreds of LEDs to illuminate the sanded acrylic rods that she installed in the tower made of bike wheels! The control circuit needs a separate power supply to operate and I designed the system so that this power could come from 2 9 Volt batteries if the Tower was to be used outside and far from an outlet. These would only last for 3-4 hours. But I also provided a wall power module so that it could operate indefinitely when plugged in. The whole thing was mounted to a classic "bread board" about 12" by 16". (The term bread board comes from the early days when vacuum tube circuits were hand built by hobbyists onto wooden boards - literally bread boards.) |
contact Rebecca at:
me@rebeccaschwarz.com
See more about the Tower of Power on
Rebecca's web site.
