# Newbie in need of Science Fair Help...Please

Discussion in 'Electronic Basics' started by Gill, Oct 13, 2004.

1. ### GillGuest

Hi, I'm hoping someone out there can help me. I have a seventh grade son
who must do a Science Fair project. He has chosen to do a project based on
"Alternative Energy". His goal is to power his GameBoy using some form of
power other than batteries or electricity. Any and all alternative energy
sources are being considered.

The problem is that we have been unable to find any information that will
help us to achieve his goal. We have been to the library a number of times;
we have checked the book store; stopped in at Radio Shack; and have surfed
the Internet - all without luck. We are able to find books and websites
about Alternative Energy but they all just tell about what other energy
sources are out there (water, solar, static, etc.) but not information on
how to harness that energy and convert it to power for a particular device.

in kids pedaling a bicycle but I can't find a "how to" for that either.
We've all seen the in Science books about powering a digital clock or
flashlight battery with a potato or lemon...could a series of potatoes
supply the 3 volts needed? We have tossed around a number of possible
approaches, including: potatoes; bicycle power; solar power; hand crank;
possible incorporation of a car alternator; and many more.

Any information on where to find instuctions for harnessing and converting
alternative energy (or any other insight you might have) would be very much
appreciated.

Thank you,

Renee

2. ### Tom MacIntyreGuest

A Game Boy is likely to not like unregulated power, so you may want to
consider that. A diode bridge, a filter capacitor, a zener diode, and
the appropriate dropping resistor would possibly do the trick in the
right configuration. They may be internally regulated, though...maybe
someone here knows if that is the case.

I don't know what the voltage requirement is (6 VDC?). Perhaps some
kind of miniature windmill turning a generator, or motor connected in
reverse, driven by a variable fan? Hmmm...that may be out, as
something is needed to drive the fan...some kind of hand-cranked or
foot-cranked affair, maybe.

My son just informed me that a Game Boy is 2 cells/3 VDC...that's good
news, because it puts it closer to the range that the fruit and
vegetable battery can possibly provide, although I don't know if
you'll get enough power without a fairly substantial series/parallel
setup, and .

I'll try to check into this a bit more later; it looks like you've
done your share of research, so it isn't like you're asking for
someone to do the project for you (which would be frowned upon most
times at least).

Tom

3. ### Rich GriseGuest

Design a VR suit that's coupled with cranks and levers and pushrods and
stuff to a generator, so the game is powered by the player's own movements.

;-)

Good Luck!
Rich

4. ### CFoley1064Guest

Subject: Newbie in need of Science Fair Help...Please

First of all, voice of experience. Don't use the Nintendo -- it's too
expensive. You don't want to put anything in your kid's science project that
you can't afford to risk by smoking, losing, or having stolen. The Game Boy
qualifies on all three counts, especially the last. In addition, Game Boys
require a two part adapter -- one part replaces the battery, and the second is
the AC adapter. You'll have to buy one of those to get to the point that you
can apply power. Looks like too big of an investment. Go to Wal-Mart and get
one of those \$10.00 LCD screen handheld games instead. Make sure they've got a
few in stock so you can buy two. But before you do, determine what kind of
alternative power you want to do, and how many batteries you're trying to
replace. Most of these handheld games require two (3V), 3 (4.5V), or 4 (6V) AA
batteries. By the way, it also might help while you're at Wal-Mart to get one
of those cheapie \$10.00 digital voltmeters. You'll need it for the project,
science project) as well as providing a check on your power sources before you
plug anything in. Remember, connecting power backwards with any of these
things usually means you let the smoke out.

The lemon idea with pennies and zinc mail is interesting. You're creating a
battery cell with a potential of about 0.9V. The problem is, the cell is only
capable of providing a couple of mA before it bogs down. Most of that has to
do with the surface area of copper and zinc which comes in contact with the
acetic acid of the battery. Let's say you've got 3 lemons in series, which
would make a 2.7V battery. You would then choose a two battery handheld LCD
game, connect your batteries together with small alligator clips, and hook your
lemons battery up to the + and - battery clips inside the game with the free
ends of the test leads (view in fixed font or M\$ Notepad):

.---------------------------.
| Game |
| Connect Lemons to Battery |
| Clips Using Gator Clips |
| |
| + - |
'-----o---------------o-----'
| |
| |
.-----' '--------.
| |
| |
| .-. .-. .-. |
'-----( L )--( L )--( L )------'
'-' '-' '-'
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

If the battery bogs down, you might have a problem. One way to solve it is to
put a couple of 3-lemon battery strings in parallel. Make sure you've got the
polarity straight.

Another option would be a bike generator. You can get these inexpensively from
many sources. One good source is the retired guy down the street who fixes up
and sells used bikes as a hobby. He's probably got a couple of these
generators in his junkbox, and will be willing to part with them for a couple
of bucks and a six of his favorite malt libation. If you've got an exercise
bike lurking around, you can hook up the bike generator to provide a power
source. You may come up with another way to crank the generator besides
spinning on a bike tire sidewall, but that's up to you. Bicycle generators
usually put out AC (alternating current). They will typically produce 6 Volts
AC at up to 1/2 Amp. You won't need anywhere near that much current, so you're
OK there. What you will need is a way to rectify that power, and regulate it
so it has a steady voltage like a battery. This is one which is particularly
good for a 6V toy (4 AA batteries) or 4.5V (3 AA batteries). In order to get
safe DC power from the generator AC, you will need something like this (view in

.-----------.
| | ____
| | D | | +
| o-----o--->|---o---------o--|7806|--o--o
| Bike | | | | |____| |
| Generator | | D | | | |
| | '---|<-----. +| | +|
| | | | --- | --- 6 Volts
| | D | | --- | ---
| | .--->|---' | C1| | C2|
| o-----o | | | |
| | | D | | | |
| | '---|<-----o-------o----o-----o--o
'-----------' -

created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

The 6 VAC is retified by the 4 diodes labelled D. Charge is stored on
capacitor C1 such that the DC voltage input to the voltage regulator will be
near the peak DC produced by the generator (about 9VDC). The 7806 voltage
regulator drops and smooths out the voltage to 6VDC, with cap C2 required to
ensure stability of the regulator. I would choose 1N5819 diodes for D, a
1000uF 25V cap for C1, and a 10uF 25V cap for C2. All of these, along with the
7806 regulator and perfboard to put the components on, are available from
Mouser.com or Radio Shack. E-mail me if you need help getting the components
together. Please put "Science Project" in the heading, or it will get sent to
dev.null.

The above circuit is good for a 4 battery device. If you want a 3 battery
device, choose a 7805 regulator in place of the 7806. That will give you 5VDC,
which is close enough to 4.5V for what we're doing here.

A third option is solar power. Radio Shack has a 6V 50mA solar panel for \$16
USD which will fill the bill perfectly for a 4-battery device. You just hook
up the red wire to the + and the black wire to the - battery terminals on the
battery clips of the toy. Simple and straightforward.

For your project, you might want to try to find a 3V toy and go with the lemon
battery, as well as the 6V toy and go with the generator and rectifier/voltage
regulator. I'm not sure what kind of data you can get from the solar cell
that's useful in a science project. Remember, by 7th grade they're supposed to
be able to do a paper with hypthesis, data, and writeup. With a cheapie
voltmeter you will be able to get voltage readings, and you might be able to
get something of a DC current reading, too. That will be enough for what you
need.

When doing these things, it's really good to teach the First Axiom Of
Engineering Projects, taught to me by a wise engineer years ago:

*** HURRY EARLY ***

Hopefully this isn't due tomorrow next week (unfortunately, that was the case
with both of my kids). Deciding what to do and getting the components together
is a good first step, and should be done as soon as possible.

Good luck
Chris

5. ### GillGuest

Thank you Tom for your help. My husband thought that a diode would need to
be used...he seemed to remember that bit of information from his highschool
days. Yes, we've been trying to do research...that's why it has been so
frustrating not to have made more progress to this point. It's great
getting different perspectives from others...we appreciate the feedback and
help.

Renee

6. ### GillGuest

Well Rich...we like the VR suit idea...unfortunately if we haven't been able
to find the needed info for harnessing alternative energy, I guess I'm not
too hopeful for finding VR suit instructions...

Maybe we can save the VR idea for my son's highschool years.

Thanks

Renee