You can get electricity from a Potato, but..... 2

[nornrich]

All,

I am looking for a means to power an LED through vibration. The vibration would come from an engine being on and the LED would only be on when the engine is on. I've seen flashlights that you can shake and they will store a charge for a period of time. I am looking for something that will provide a continuous flow of current and also charge a rechargable battery at the same time.

Regards,

Rich....

Richard Nornhold, PE

 

[Skogsgurra]

It all depends on what vibration frequency and amplitude you have available. A little device with a coil and a neodym or other rare earth magnet will certainly generate power enough to light an LED. It is mostly a question of selecting the right number of turns and the right magnet. I would say it is much easier than making a potato light the LED.

Gunnar Englund

http://www.gke.org

 

[nornrich]

skogsgurra,

What if we vibrated the potato? Would this make it easier?

Regards,

Rich....

Richard Nornhold, PE

 

[logbook]

Vibration is a small movement whereas a larger movement is preferable. If either the coil or the magnet were lightly suspended by springs (or springy material) the motion amplitude could be amplified to give a more usable motion range.

I guess the first step is to try some simple experiments with coils and magnets to see what order of magnitude you need. Make sure you use schottkey diode(s). Don't use a bridge rectifier. Either do it half wave or centre tap the coil and do a bi-phase bridge (two diodes).

 

[nornrich]

logbook,

We were figuring on using springs to amplify the motion. On the electrical side of things, please explain why the use of shotkey diodes? Is this just for rectification purposes or is this to protect the flow of current back from the batteries? Sorry to ask, but you are talking to a slow witted mechancial engineer.

Regards,

Rich....

Richard Nornhold, PE

 

[IRstuff]

The Shottky diodes, presumably, were suggested because their forward voltage drops are smaller than that of standard junction diodes, ~0.2V vs. ~0.7V.

TTFN

 

[itsmoked]

You presumably have a rotating shaft somewhere... Why screw with this 100 hour project? You could run a toy motor with an O-ring and have some useful energy. Or use a rubber follower and just let it run on any rotating member. Or worse but still better 'make' a generator by clamping two magnets on a shaft and have them pass a coil. (still a pain in the butt)

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[MacGyverS2000]

Any chance of wrapping a few coils around your alternator on the outside? Better yet, just tap into the alternator itself


Dan - Owner

http://www.Hi-TecDesigns.com

 

[Skogsgurra]

I would skip the diodes. Just connect the AC to the LED. You will not have enough voltage to destroy the LED with reverse voltage. And your magnetic circuit will not saturate from the DC component. No probs. And, yes, shaking the potato will probably be good. But it will not light the LED.

Gunnar Englund

http://www.gke.org

 

[nbucska]

What about using piezoelectric generator with neon lamp?


Plesae read FAQ240-1032
My WEB: <

http://geocities.com/nbucska/>

 

[geekEE]

Getting an LED to light with power generated by vibration is probably not too difficult to do, but charging batteries could be substantially more difficult. I agree with ItSmoked and Macgyvers2000; can you just generate the power from the rotational motion somewhere on the engine? You'd probably be able to get a LOT more power, much more easily.

 

[nbucska]

Nornrich:
Can you tell us more about your application and engine?

Plesae read FAQ240-1032
My WEB: <

http://geocities.com/nbucska/>

 

[OperaHouse]

I question whether you could generate enough. If the engine shakes that much, you have a design problem. Second problem is are you going to read this in sunlight? I have my doubts of the success of this project.

 

[VEBill]

Prediction: another long thread...

 

[analogkid2digitalman]

If you slice the potatoe, will you have a self powering chip?

Will dicing a potatoe cube it's power output?

Will you get more voltage from a potatoe if you slice it up and then stack the slices (AKA Pringle's cell)?

Are Potatoe Buds (dried potatoe flakes) AKA a 'dry cell'?

This could get long indeed...

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"It's the questions that drive us"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 

[itsmoked]

Hahahah not with my help! Besides why wouldn't the LED and diodes and 'what all' shake apart soon anyway..

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[Warpspeed]

Is this a school project ?

I recall when I was about five, we used to stick plastic features onto potatoes to make funny faces. This will not help you with your project, But I thought I would just mention it.

Making an engine driven vibrating potato light up sounds like much more fun. We never had anything like that when I was a kid {

 

[OperaHouse]

Just don't fry the potato(e) (big fan of Dan, who was that Vice President). Oil is an insulator!

 

[Skogsgurra]

Easy now. There are people trying to solve an engineering problem here.

Analysis:
Q1: Is this a school problem?
A1: Do not think so. Then we would have input like "A piece of machinery is weghing 10 pounds. It contains a rotating member weighing 5 pounds. The rotational speed is 1800 RPM and there is an imbalance that can be represented by a 2 oz mass positioned two inches off the rotational axis.

We do not have such a specification -> Probably not a school question.

Q2: Would a school kid be mature enough to make the heading about the potato?
A2: No. School kids are way too serious about "science".

Q3: Will there ever be enough energy to light an LED?
A3: Yes, probably. It takes only a few milliwatts to make one of those new LEDs shine very bright.

Conclusion: This is serious engineering stuff. Don't ridicule us/those that work on the problem. ;-)

BTW, DQ is one of my absolute favourites. A natural born comedian!

Gunnar Englund

http://www.gke.org

 

[Warpspeed]

You are quite right Gunnar.

A suitable ac voltage should light a Led, without any additional rectification. And I like the resonance idea, either with a mechanical spring/mass, or a tuned LC tank circuit. You would just need to be fairly sure of your exact vibration frequency, or it might cause more problems than it solves.