This is my first post and if this isn't the right forum, please let me know and I'll move.

My second grade daughter the following idea for her science fair project: generate electricity from her hamster while it runs on its wheel.

I thought this sounded fun, so I did some reading. The stuff I found on the web said what I found as well.

My first thought was to use an electric motor that is turned by the wheel (which is turned by the hamster) and hook that up to a flashlight light bulb. I tried this with a generic electric motor from Radio Shack that's ~1.5V and ~7,000 RPM and a generic flashlight bulb. The bulb lights nicely with a 1.5V battery and the motor spins nicely with a 1.5V battery.

However, spinning the wheel myself and using that to spin the motor (via rubber band) gives only a few hundred mV and not nearly enough to light the bulb that I can see.

So I'm wondering, is there some other kind of bulb or perhaps a LED that I can use that will visibly light with a few hundred mV?

If so, where could I find them.

Thanks.

 

Welcome to AAC. Your post is perfect.

Interesting idea. Radio Shack sells several motors, have you tried a higher voltage, like 9V? I suspect the higher voltage the better, because there isn't a way for a hamster to turn it as fast as it would spin at it's rated voltage.

Instead of a light bulb, use two bare LED back to back, since you don't know which way the critter will spin the wheel. That way one of them will get power, and they don't require nearly the juice an incandescent bulb does.

I'd try the LEDs first, red ones, since they use the least voltage. Normally a LED absolutely requires a resistor, but your setup sounds so power starved I don't think it is necessary for this experiment.

 

You need to 'gear it up'. Look into some cheap(<$10) electric toy cars. They have a gear train to turn a 5,000-10,000 RPM motor shaft into a reasonable 400 RPM toy car axle.

These motors have 2 poles. if you built...IF you built a generator with 20 or 24 poles instead, then 1000 RPM would get you the same output as 10,000 RPM does in a 2 pole.

Unlikely that you will go to that trouble for this.

One LARGE pulley groove, say the same diameter as the hamster wheel; leading to a very small pulley on the motor, should give you the 'gearing up' ratio you would need.

 

I have this vision of the hamster at 100° on the wheel, hanging on for dear life. They are very light weight, even though they tend to look chubby. They also like to climb, I've seen them hanging from the top of the cage with one toe nail. My kids had several over the years. My brother was supposed to take care of snowball whilst the girl was visiting grandparents for a week. We ran out of food, and he'd never heard about the problems with rice. It was very sad, especially his explaining to her what had happened. In case you haven't heard, dry rice swells a lot when mixed with water, so if an animal eats it, then gets a drink...

It's why they don't use dry rice at weddings any more, and use birdseed instead.

 

Thanks for the replies! I'll try them out tomorrow (or next weekend as time permits) and let you know how it goes!

As for the resistor, I felt the same way with the power being minimal, I was going to skip it.

 

This is my rubber band drive idea.

 

This is my rubber band drive idea.

I think I'm going to need a bigger rubber band. But that would work nicely with one of the hamster wheels we have!

 

Let's keep this thread under wraps. If it gets leaked to PETA they'll go ballistic!

On a more serious note; if you find that your Hamster can't get up enough steam to give you satisfactory LED brilliance, consider a capacitive discharge circuit that would flash the LED.

 

This is my rubber band drive idea.

Nice 3D artwork!

 

Let's keep this thread under wraps. If it gets leaked to PETA they'll go ballistic!

On a more serious note; if you find that your Hamster can't get up enough steam to give you satisfactory LED brilliance, consider a capacitive discharge circuit that would flash the LED.

Thanks! I'll keep that in mind, both about PETA and the discharge circuit.

 

Take a look into PMA (permanent magnet alternator) for hamster wheels. I've seen several that work pretty well. Basically, the magnets get attached to the perimeter of the wheel and pass by a copper wire coil. So the wheel itself is the alternator. This arrangement adds no drag on the wheel other than the power drawn off for lighting.

Definitely use an LED for the light. The principal drawback is that it'll make no light until you exceed the forward voltage, but the low power draw is critical.

On the downside, it takes a bit more DIY to build this. One thing I've played with that might work is a drive motor out of an old VCR. It's squat and wide - maybe 2 inches wide and only a 1/4" thick. I can easily spin it by hand and light an LED.

 

Here you go Reel drive motor from an ancient JVC HR2700 VCR Very easy to turn is a 12v motor, turning with fingers will light either LED in either direction ( took about 20 photos to get 3)

 

A few more motors from early 80s VCRs, capstan drive motors & belts. Have checked & these also drive LEDS at low RPM

 

little hammy has a insatisfiable taste for rubber. It takes 3-4 days for it's plugged gut to be outwardly noticeable, but it's too late then. Actually it's generally too late after he ingests it.

You might try one of those ball chains, common in sinks linked to the stopper, as a drive chain to the exterior motor, cause he'll chew the plastic sheave, wires, and what ever else his teeth can get through.

 

little hammy has a insatisfiable taste for rubber. It takes 3-4 days for it's plugged gut to be outwardly noticeable, but it's too late then. Actually it's generally too late after he ingests it.

Perhaps a Gear-head motor connected directly to the Hamster wheel axle. There are a few here besides this one.
http://www.mpja.com/prodinfo.asp?number=16815+MD

 

To beat rubber eating hamsters put tread mill to one side of cage & run a shaft to the outside of cage for pulleys. That should stop them.

 

I doubt the hamster will have enough grunt to turn a gearhead motor.

 

I doubt the hamster will have enough grunt to turn a gearhead motor.

I doubt that the ratio of the armature to output shaft is an more severe than the ratio of the belt systems we've been discussing.

 

I'm wondering what the hampster will think of all this. SCARY?!?

I'm not too sure about the rubber band coupling, but I think some gearing to increase the speed of the motor would be benificial.

 

To mutch time on my hands today. Checked RPM to get LEDs to light, starts @ 500RPM & ok @ 640RPM.