The Cyclenator: A Bike Generator-Powered Cell Phone Charger
Selase Asamoa-Tutu
Summary:
This project involves the use of a bicycle light generator (dynamo) to power a cell
phone by simply pedaling. The problem to be solved here is to design a cell phone
charger for everyday bike users to enable them charge their cell phones as they make
their daily bike commute to and from work or their bike ride after their daily activities as
a workout or just for leisure. It was also made to solve the issue of people who rely on
cell phones for business but have to walk distances to pay to get them charged, mostly in
third world countries. These people could get a bike and have this portable charger, that
way as they bike around, they charge their phones without having to continue paying on a
daily basis to get their phones charged.
The design goal is to make an eco-friendly charger that would produce the right
amount of voltage and current to charge the cell phone, will be easy to install, will be
light in weight, will be durable to withstand harsh weather conditions and also will be
affordable enough for the people in third world countries to purchase. Several concepts
were considered to meet these principle requirements. The concept selected included a
bike generator which is just a regular bicycle dynamo with a clamp to hold it to the bike
frame. A voltage regulator was to be fabricated to allow the right amount of voltage to
enter the cell phone, with a metallic casing to protect it. The third part of this concept was
a cell phone case with Velcro straps to hold it to the bike frame or handle bars. Other
concepts involved using a “match box” style case, the hand, a breast pocket of a shirt and
even a basket as ways and means of holding the cell phone. Generators considered
included solar and wind powered generators, among many others. Also, bike generators
that had built in voltage regulators were considered but were rather difficult to come by.
The final design involves using a cell phone case and Velcro straps to hold the
cell phone at the desired position on the bike frame and a dynamo generator, which is
also clamped to the bike frame, to create electrical energy. A voltage regulator box will
be fabricated and added to the final design. This consists of a rectifier to convert the up
and down un-steady AC to a DC, a capacitor to level out the DC voltage and produce a
steady inflow voltage to the voltage regulator and then the voltage regulator which allows
only a steady 5 volts going into the cell phone. The voltage regulator component plays a
very important part in this fabricated unit because it prevents the cell phone battery from
overcharging and burning up.
The design works and positive results were obtained. The voltage regulator fabricated
was to produce at most 5 V and 0.008 A; it met this requirement. It was able to produce a
voltage not higher than 5.024 V and 0.008 A. The lowest input voltage applied was 7.3 V
with a current of 0.02 A and anything below this failed to charge the phone. A maximum
input of about 11 V and 0.45 A was channeled through the voltage regulator and it was
still capable of converting it to the desired input needed. This was good to see since it
meant the battery of the cell phone wouldn’t overcharge and burn out. The case for the
voltage regulator also served its purpose. It was made of aluminum and was very strong
and durable. It will be able to withstand harsh weather conditions. The Velcro straps are
also able to hold the different components of the design at their desired positions on the
bike frame. The bike generator produces enough electrical energy upon slight pedaling.
This was perfect to charge the cell phone. Last but not the least, the cell phone case was
able to hold cell phone well and provides the necessary protection to it.