Well now we're niggling but power drawn off directly puts load back to hammy. So leaving half the cycle unloaded will truly reduce the load on hammy and still produce light. If hammy has no problem, obviously you could keep adding LEDs or other loads until he does.

A human riding a bicycle and expending maybe 150 watts will very definitely "feel" the drag of a 3W or 6W lighting system, as little as a 2% drag on total energy expenditure. I'm sure hammy is no different in that regard. Just by a rough estimate of 1 watt per pound for an exercising mammal, a big hamster might jog at 500mW or so. An LED at 10mA and 3v Vf needs 30mW. Back-of-the-napkin speaking, this is a non-trivial drag on the little guy.

 

Thanks for that little prompt Wayneh. just went out & tried it without a diode on the VCR drum motor, & the LED is brighter at lower RPM.

 

I used to have hamsters. Alas it was before I knew anything about electricity. This is a great idea.

How about we shut down the Japanese nuke power plant, and replace it with over 9000 hamsters!!! Problem solved.

 

Here's the update for this weekend, about three weeks before the science fair.

We had to go to PetCo to pick up a better hamster wheel, one that had a big radius that I could wrap the rubber band around. The biggest they had was one with an 8.5" diameter which gives a big lever arm going down to the axel of the motor.

The big challenge today was to put together a belt out of rubber bands to go from the wheel to the motor. I tried stapling three rubber bands together, but that got stuck on the staples, so I tied three rubber bands together. That worked better, at least it didn't get stuck, though it was far from smooth.

As someone pointed out above, the gearing ratio from big to small really helps (as does the 9V motor) and a red LED lights pretty easily with my daughter spinning the wheel pretty slowly. We've yet to try it with the hamster, I'll have to fasten everything down before we do that (so far I've been holding things together by hand and using a breadboard).

When we get it working, we'll put up a video on YouTube and I'll post a link here.

Thanks to everyone who's contributed to this five page thread!

 

Old VCR drive belts or the belt off a belt drive turntable are far better to use than rubber bands a lot less drag.

 

I've been pondering the past few days, about where and how to get large diameter rubber bands.

It seems so simple after it occured to me, and it is really. Inner Tubes for bicycle tires. Some relaxed razor blade work with a metal straight edge and a new razor blade. Instant rubber bands.

 

Just had to say, this thread has been very enjoyable.

Good luck!

 

How about we shut down the Japanese nuke power plant, and replace it with over 9000 hamsters!!! Problem solved.

If only it were that easy! If my rough estimate earlier is even close, that Hammy might generate 500mW under full load, and assuming you could capture all of it, you'd need about 10 million of the little guys to replace the lost capacity in Japan. That's a lot of squeaking.

 

If only it were that easy! If my rough estimate earlier is even close, that Hammy might generate 500mW under full load, and assuming you could capture all of it, you'd need about 10 million of the little guys to replace the lost capacity in Japan. That's a lot of squeaking.

And a lot of wood chips and "Hammy pellets".

 

Caffeine anyone? Micro doses, those guys are pretty small.

 

Old VCR drive belts or the belt off a belt drive turntable are far better to use than rubber bands a lot less drag.

Thanks for those ideas! I've got a broken VCR and turntable laying around that I'll scavenge for belts too. I'll also look in to the bicycle inner tubes, my wife is a cyclist, so she might have some old inner tubes I could try.

The science fair is in a week and a half. We've got all the parts and tested things out by hand (still no hamster test yet). The red LED lights easily when the big wheel is turned. This weekend we'll assemble everything and put Chestnut the hamster to work.

If all goes well, we'll post a video on YouTube.

P.S. Sorry for all the repetition.

 

Yes JB were still watching with interest!!

 

Today my daughter and I put everything together and typed up some of the stuff for her report (I need to get her to add something about this thread and all your input: over 50 replies and almost 1,200 views!).

We tried the belt from my broken turn table, but it didn't work (maybe that's why the turn table was broken). It didn't seem to grip the drive of the motor enough and it wasn't quite big enough. We had some success by using an enormous rubber band. It was the kind that artists use to secure their portfolios. We had to slice it length-wise to make it thinner. Even that wasn't perfect as it makes the hamster wheel pretty hard to turn, but when it does turn, it lights the LED easily.

Here's a link to the video we put on YouTube (warning about the kids' hamster song for the soundtrack): http://www.youtube.com/watch?v=k0msVbqGuEo we'll put that on her poster too and some pictures showing the LED on with the hamster in the wheel (albeit with a little help turning it).

Thanks again for all the input! We couldn't have done it with out all the help.

 

You might try placing the rubber band further back on the wheel.
Is the rubber band slipping on the motor shaft? If so winding it around it once might help it grip it better.

 

Doesnt take mutch to amuse me!