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rotate
04-20-2010, 12:37 AM
I've been spending the last few weeks helping my 13 year old nephew on a science fair project. It was a good opportunity to teach him basics of machining, welding, and woodworking. To make a long story short, here are the pictures of the finished product. It's a portable human powered generator. Because this is just a proof of concept, the portability hasn't been demonstrated. When the teeter-totter is rocked at about 1 steps/second, it products about 8W which isn't that bad. It's definitely enough to charge a cellphone and light up 144 LEDs very brightly.

I have some videos of it in operation which I'll post on YouTube later.

BTW, he won gold! :)

http://i7.photobucket.com/albums/y287/rotate85/DSC02238.jpg

http://i7.photobucket.com/albums/y287/rotate85/DSC02241.jpg

http://i7.photobucket.com/albums/y287/rotate85/DSC02242.jpg

rotate
04-20-2010, 12:37 AM
http://i7.photobucket.com/albums/y287/rotate85/DSC02240.jpg

http://i7.photobucket.com/albums/y287/rotate85/DSC02239.jpg

rdfeil
04-20-2010, 01:04 AM
Rotate that is a great project to learn from and I am sure your nephew learned a lot. The drive system looks good too. Looking at the pictures I assume the bridge rectifier is because the motor (generator) direction reverses as the teeter totter rocks back and forth and the bridge keeps tho output polarity constant. Is this right?
No matter what, it is an excellent project for a 13 year old and you must be the favorite uncle :D :D .

Keep the kid interested in science, machining, building things and MOST IMPORTANT.... Learning. He will be a better man for the experience with your help.

Robin

The Artful Bodger
04-20-2010, 01:05 AM
A very nice piece of work and I am sure great learning experience for all concerned!:p

jnissen
04-20-2010, 01:13 AM
Edit.... Please delete.

jnissen
04-20-2010, 01:20 AM
Neat stuff there. I do wonder how much of the work was your nephew and how much was it your work? I don't have any problem with kid doing a neat project but it has to be their work. I assist my son on his projects but it's all his work. I help proof read the write up (many many iterations!) so I know how difficult it is. Likewise I give him pointers and suggestions in the shop but he has got to do the design, the research, the actual machine work, etc... Yes they sometimes look imperfect but he knows the material and builds on it for the next year. It must be working as he won state this year.

If it was 100% his work then that is great. I just thought it looked a bit to clean for a 13 year old. BTW - Did he participate or get invited to ISWEEP? It's an international fair for energy, engineering, and enviorment held each year in Houston TX? It just wrapped up yesterday and not sure if he was there or not?

bborr01
04-20-2010, 01:21 AM
Rotate,

Pretty good stuff there.

Did you get the idea from sheriff Joe Arpaio from arizona?

He's the guy who brought back chain gangs, houses prisoners in tents in the desert and makes them wear pink underwear, among other things.

I just read that he has begun to allow prisoners to watch tv but there is a catch.

They have to sit on a stationary bicycle that is hooked to a generator that powers the televisions.

It is reportedly going over pretty well.

Brian

dp
04-20-2010, 01:26 AM
Give that poor kid a flywheel! :) Very nice project.

rotate
04-20-2010, 01:32 AM
If it was 100% his work then that is great. I just thought it looked a bit to clean for a 13 year old. BTW - Did he participate or get invited to ISWEEP? It's an international fair for energy, engineering, and enviorment held each year in Houston TX? It just wrapped up yesterday and not sure if he was there or not?

I know what you mean. First of all, no science fair project of any quality is done without a mentor. I made sure that I spent many many hours going over the theory of welding, mechanical design, and electromagnetic theory. He know how everything works from how MDF board is made to Faraday's theory. I went over the design and demonstrated first what to do, and after that he did all the work under my supervision. The reason why everything looks so neat is because we planned very carefully and I made him redo anything that wasn't exactly to the plan. I would say that at least 80% of the work was done by him. It helps to have a child who's eager to learn.

Evan
04-20-2010, 01:48 AM
Very nice project and my congratulations to your son since I presume he did most of the work.

It does bring up a question about the purpose of a science fair and what is expected from the entrants.

A science fair is supposed to be a display of projects that are intended to inquire about some aspect of the world around us and it's inhabitants. To this end a science fair project should start by asking a question about something that doesn't have an obvious or trivial answer. The goal then is to formulate experiments that can serve to illuminate the question and to do so by using the scientific method.

Your son's project falls in the category of demonstration. While there is no doubt that it was a valuable learning experience it doesn't meet the criteria of inquiry that a true science project should address.

As an example, the generator could serve to answer the question of just how much power a human can produce with that apparatus over a set period of time. To further that line of investigation he could also determine how much time on the generator would be required to charge a battery to provide for the operation of various devices. The amount of effort required could also be approximated by measuring breath and heart rates of volunteers in comparison to well documented activities such as stair climbing.

It is that sort of additional knowledge based goal setting and research that takes a project out of the category of demonstration and makes it a contender for national competition and recognition.

rotate
04-20-2010, 02:09 AM
Your son's project falls in the category of demonstration. While there is no doubt that it was a valuable learning experience it doesn't meet the criteria of inquiry that a true science project should address.

It was my nephew that I was helping. What I didn't show was all the experiment that he did using the device and the result was posted on the display board.

The hypothesis of the project was to determine whether a portable human powered generator can generate enough electricity to charge portable electronics (in an effort to offset carbon foot print), and also provide power to rural villages in developing countries where CFL/LED could be used to light the homes. Unfortunately in 2010, almost all science fair projects have to have some environmental or social slant. Sigh...this was definitely not the case when I enter science fair in my high school years. We were allowed to building things just for the sake of the technology.

The power output was determined by submerging a resistor (load) in a known volume of volume (in a thermos) and measuring the rise in temperature. He did this with different loads and different rates. Lots of graphs and tables were obtains, which lead to the conclusion that a portable generator like this could indeed be used to power portable electronics and using battery light number of homes.

There was a genuine scientific inquiry which in theory could have been work out based on energy output of human muscles, but the nature of experiment is to demonstrate that a theory is correct. Or at least show that a particular method of harnessing human muscle power is technically possible and practical.

Pete F
04-20-2010, 02:16 AM
That looks like a really nice job. If he didn't walk out on you before the end (with all the "do it over if you didn't do it right the first time" ;)), I think you have an extraordinary young engineer there.

There are certain professions that really can't be done properly by someone who is not capable of that level of quality even at a young age. Sounds like your nephew is one of them. Keep him engaged!

-Pete

Evan
04-20-2010, 02:52 AM
There was a genuine scientific inquiry .....


Excellent. Exploring environmental impact is a very broad field and full of questions that need answers.

batt-man
04-20-2010, 03:17 AM
sounds like a good project to me...

there was a program on TV recently where they setup a human power station (people on bicycles with back wheel linked to a dynamo) linked to a "regular" house and got a family to live in this house for a day. Every time they used a kettle or the oven you got to see a load of people on bikes start sweating and cursing again..

You also saw one of the presenters cook a chicken using nothing but a couple of incandescent bulbs...

If your interested google for "bang goes the theory : the human power station"

Batt

The Artful Bodger
04-20-2010, 04:17 AM
A human powered alternator is actually a very good project for all ages. The best I can manage is a sustained 50 watts though I can peak at over 300 for a few seconds.

Evan
04-20-2010, 05:19 AM
The best I can manage is a sustained 50 watts though I can peak at over 300 for a few seconds.

In stark contrast.....:D


The Lance-Equivalent Unit, or L.E.U, is the maximum sustained power output of Lance Armstrong, about 500 Watts. By sustained, we mean more than a few minutes. In a bicycle race like the Tour De France, the shortest time trial is about 20-30 minutes of racing. Lance can continuously output approximately 500 Watts during this type of short race.

The Artful Bodger
04-20-2010, 05:44 AM
In stark contrast.....:D

I am suprised Evan that you did not note that my figure is for output from the machine whereas Lance's output would be input to his machine. If my machine is less than 60% efficient it would mean I can put out more than one L.E.U., for a few seconds!:D

Black_Moons
04-20-2010, 06:12 AM
Evan makes a good point, but I like the more extream idea of human loading:

Attach loads untill volenteers can't keep it up for more then 5 mins :)

bob ward
04-20-2010, 06:41 AM
One of the famous (in Australia at least) applications of human power generation was the pedal radio, used widely through the outback from the mid 20s

http://www.antiqueradio.com/traeger_pedal_07-99.html

oldtiffie
04-20-2010, 06:47 AM
This one is fairly topical:
http://i200.photobucket.com/albums/aa294/oldtiffie/Funnies/Help_desk1.jpg

Perhaps while he is sorting out your problem he is multi-tasking and perhaps powering this lot:
http://i200.photobucket.com/albums/aa294/oldtiffie/Funnies/Power_problem1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Funnies/Power_problem2.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Funnies/Power_problem3.jpg

A.K. Boomer
04-20-2010, 10:07 AM
It was my nephew that I was helping. What I didn't show was all the experiment that he did using the device and the result was posted on the display board.

The hypothesis of the project was to determine whether a portable human powered generator can generate enough electricity to charge portable electronics (in an effort to offset carbon foot print), and also provide power to rural villages in developing countries where CFL/LED could be used to light the homes. Unfortunately in 2010, almost all science fair projects have to have some environmental or social slant. Sigh...this was definitely not the case when I enter science fair in my high school years. We were allowed to building things just for the sake of the technology.

The power output was determined by submerging a resistor (load) in a known volume of volume (in a thermos) and measuring the rise in temperature. He did this with different loads and different rates. Lots of graphs and tables were obtains, which lead to the conclusion that a portable generator like this could indeed be used to power portable electronics and using battery light number of homes.

There was a genuine scientific inquiry which in theory could have been work out based on energy output of human muscles, but the nature of experiment is to demonstrate that a theory is correct. Or at least show that a particular method of harnessing human muscle power is technically possible and practical.


Rotate I think his project was the bomb and deserving of the gold, it's all about all the things kids learn along the way (or should be)

A couple quick notes however, If the goal is to find out what a human powered generator is capable of then one should start out with one of the most efficient designs that keeps one direction of rotation - uses a flywheel for storage - and uses the largest most efficient muscle groups in the most efficient way, also keep in mind that when it comes to things like "carbon footprints" that human power is one of the worst conversion rates going - just because its "human powered" doesn't mean its for "free"
Humans have to eat cheeseburgers to put out energies, cheeseburgers take a ton of fossil fuel to produce from the cows to the bread to the transport , now run it through the clogged up bowels of the average humanoid and very little is used to produce actual work (unless you hook up some kind of recovery pipe to capture all the flatulence)

This is a fairly efficient human powered generator, I can put this puppy way past its normal 13.7 volt operating range and you would not believe the air that it pushes - the fan is off of a V/6 Ford


http://i146.photobucket.com/albums/r249/AK_Boomer/DSC00030.jpg


Of gearing and efficiency --- we both eat it bad with gearing but your design esp. ---
anytime you need to increase speeds you create unwanted friction - your design having to be either intermittent or change directions is even worse,

Mine has a couple of "step ups" and could be improved upon - Ideally one should have a direct drive skinny generator that one straddles and uses the top outer casing as a bike seat ;>}

http://i146.photobucket.com/albums/r249/AK_Boomer/DSC00032.jpg

gnm109
04-20-2010, 01:46 PM
Edward G. Robinson and Charlton Heston had a human-powered bicycle generator that they used in their apartment in the movie Soylent Green.

I like the idea of using a bike for power.

wierdscience
04-20-2010, 01:54 PM
Nice to see kids doing something other than playing video games.




Sheriff Joe is even in on the idea;)

http://www.cbsnews.com/8301-504083_162-20001864-504083.html

The Artful Bodger
04-20-2010, 04:00 PM
http://www.thebackshed.com/Windmill/articles/PedalPower/kiwijohn/Image3.jpg

There are a few words about my 'Cyclogen' here:-
http://www.thebackshed.com/Windmill/articles/PedalPower_John.asp

dr pepper
04-20-2010, 06:43 PM
I have worked in places like that and its not very pleasant, some houses have bare wires going through holes in the wall with live mains on.

8 watts isnt bad at all for the wobbly genny, I built a small wind genny for a friends boat bound radio station and that works well, I'd like to have a go at a savonious affair using 2, 45 gal oil drums and a vehicle alty.

Those direct drive washing machine motors seem to be popular for gennys, I tried to get on here in the uk and they are not very common.

The Artful Bodger
04-20-2010, 07:00 PM
Those direct drive washing machine motors seem to be popular for gennys, I tried to get on here in the uk and they are not very common.

They are not the best for starting in light winds or for use in a pedal generator as the magentic drag (aka 'cogging') soaks up a lot of power and makes it harder to start.

I think an axial flux (as popularised by Hugh Piggot?) would be a better choice.

Paul Alciatore
04-20-2010, 10:45 PM
You did this with Photoshop, didn't you? Tell me it is Photoshop. PLEASE, tell me it is Photoshop.


.....

Perhaps while he is sorting out your problem he is multi-tasking and perhaps powering this lot:
http://i200.photobucket.com/albums/aa294/oldtiffie/Funnies/Power_problem1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Funnies/Power_problem2.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Funnies/Power_problem3.jpg

vincemulhollon
04-21-2010, 09:22 AM
I built a small wind genny for a friends boat bound radio station and that works well, I'd like to have a go at a savonious affair using 2, 45 gal oil drums and a vehicle alty.

Google "sailboat towed generator". An electric trolling motor run in reverse, more or less. Has two virtues, doesn't take up valuable deck space, and overspeeding is not an serious issue (60 MPH wind gusts "likely" but if the sailboat makes 60 MPH underway, you've got other problems). Also has disadvantage where if you thought corrosion was a problem on deck, just wait until its under water. Tiny disadvantage where it doesn't generate in port, you know, where you probably have shore power...

A land based model would be an interesting science fair project. Given a combination kid carrier bicycle trailer/jogger stroller thing, mount an alternator to it, stick some rechargeable batteries in the trailer, and push/pull behind various people and vehicles.

If you really want to get the engineers riled up, suggest towing it behind an electric car and using the alternator output to charge the electric car, perpetual motion style. That'll get them all lit up.

Evan
04-21-2010, 11:02 AM
We need better batteries. Batteries used to be horrible in terms of electrochemical efficiency and power output per kilo. Now they have advanced to being merely terrible. To really be usable we need something that can store and forward electrons with ten times the current power densities.

Of course, that presents a serious problem. Anything that can store ten times the potential energy of a current lithium-ion battery has another name. Bomb.

aboard_epsilon
04-21-2010, 11:17 AM
Look out for a UK torrent called:- "Bang Goes the Theory -The human power station"

A normal family, are put into a house, for a couple of days, unaware that all the power is coming from a building near-by, filled with 300 plus cyclists ..cycling away with generators rigged up their bikes.

You see in the film, how many cyclists are needed to power each appliance in the house, as its turned on .

This experiment was done over a couple of days ...about 8 months ago ..

You see the cyclists near exhaustion as they struggle to cope when ovens and electric showers are turned on .....think they reckon that a human is only capable of making power of long hauls at 100 watts..and short stints of 350 watts.

all the best.markj