Power (electricity) from playing?

[St Drogo]

Not sure if this goes here, but here goes:

Last night I (gasp!) had a thought. A pickup works by creating a magnetic field and "reading" the disturbances made by the moving metal of the strings, right? Well isn't that the same way a power generator works? Those have a coil that makes a magnetic field and a metal object that moves inside it to create electricity, right? Couldn't we then somehow harness the electricity we make when playing?

Now, I don't know the first thing about electricity, so I don't know if playing produces the wrong kind (like watts instead of volts or something like that), so I might be completely wrong here. Also, of course the scale at which electricity would be produced is a lot smaller, but I'm not trying to solve global warming here or make my morning toast by playing a quick slap solo (Though that would be incredibly cool ) But couldn't this power be used to, I don't know, power an active bass? They have a really low draw right? The preamp would then only be "on" the moment you strike the strings and thus provide it with power. Or maybe even better; couldn't it be used to power things like fretlight LED's or something like that that draws a low current? Think about how awesome that would be, your bass would light up and dim down in time with your playing, like an alien disco jellyfish or something.

Anyway, this may be utter genius or absolute crap, I can't really tell. Any electronic-savvy people want to weigh in here?

[superbassman2000]

Originally Posted by St Drogo

\
Now, I don't know the first thing about electricity, so I don't know if playing produces the wrong kind (like watts instead of volts or something like that), so I might be completely wrong here. Also, of course the scale at which electricity would be produced is a lot smaller, but I'm not trying to solve global warming here or make my morning toast by playing a quick slap solo (Though that would be incredibly cool ) But couldn't this power be used to, I don't know, power an active bass?

I don't know a whole lot about the subject, but my guess is that it wouldn't make as much electricity as would be needed by a preamp or toaster

of course, that being said, here's this
http://www.youtube.com/watch?v=Frm_sn3G0As
i don't know if it helps or not

[R. Laevinus]

Great thought, but...

A: The power produced is incredibly small. We're talking less than .5 volts, typically. Some heavier players with overwound pups may average 1 or 1.5 volts. I'd say that, absolute tops, you're looking at 5 volts. TOPS. Seeing as active pres in basses are generally wired to use 9-volt power, that could be a problem, no?

B: It's AC current. You'd need DC for LEDs, pres, etc.

C: Power output fluctuates, as you mentioned - so things wouldn't work with any reliability.

D: Perhaps most importantly - the power produced is your signal. Tapping that signal off in whole or in part will have a negative effect on your tone. Personally, I say **** the planet, I wanna hear my bass!


HOWEVER - a circuit could, theoretically, be designed which would siphon off infinitesimal quantities of power, and trickle charge a capacitor with it - that capacitor could then be used as an emergency backup power source with which to finish out a song in the event that your battery dies?

...I'd say that'd be way more trouble than it's worth, though.

[line6man]

You would be pushing it to even generate enough power to run a wristwatch.

Aside from the extremely low voltage and current being generated, the amplitude and frequency of the signal vary constantly, which would make it difficult to rectify and regulate into a steady DC voltage source to power any small electronic device.

[Diogenes]

You'd be better off learning to play a hurdy-gurdy. You could then use the crank to not only turn the wheel but a generator as well which can then power a small amp.

[St Drogo]

Haha, okay then, looks like I need to think this through a bit more. I ahven't even thought of what you mention, that the power in fact is the signal, so this idea would be detrimental to mah tone.

But maybe you could add a pickup that's dedicated to volt output. Like, next to the pickup that's there for your sound. I'd put that right up there, as near to the neck as you can get it, because the bigger the pick up string amplitude, the bigger the voltage, right? Also, Laevinus mentioned overwound pu's generate more power. So as this pu would be a dedicated powerpickerupper, you could overwound this as much as you'd like, seeing as it doesn't have to sound good. As long as you keep the magnetic field small enough to not completely muffle the strings (like on the MM sabre). Maybe you could add a few more of those once you've reached the limit of what one of those can do.

It's now getting a bit impractical, sure, but just for argument's sake.

What is the voltage you produce determined by? I guess the amount of metal that moves, so that would be stringguage. Amplitude, as I guessed above. Magnetic field strength? So maybe you could use neodymium mags? anything else?

[St Drogo]

By the way, that chainsaw vid was really cool.

[Basschair]

Movin' to.........pups and electronics?

[St Drogo]

Yeah sure, that may be a better suited forum, thanks.

[renniw]

In theory, it works, just think to those flashlights that you shake a metal core (magnet) trough a coil to make it light with some sort of circuitry (capacitors) to switch ac to dc

http://www.flashlightreviews.com/rev...ghtstar2sc.htm

IMO to make it work properly, You'll need a "sound" coil to pick string noise (some call this music....), an another coil (huge) to make power.

In theory, it would work, in real life, I doubt it.... the coil to power up bass electronics requires a really big coil...

[grisezd]

There is a pretty good drawback to adding a "generator" pickup, and that would be to make it powerful enough to be worthwhile you'd have to strum the strings constantly, with much vinegar, to keep the power flowing. And forget sustain. Strings would just stop cold!

That having been said I like where you are going with this. There is a lot of power being needlessly wasted in our every day lives. Think about a car's shock absorbers. The car wheels bang up and down all day over the road, the springs keep you comfortable and the dampers keep the oscillations down. Like a string mute, but huge. Dampers get really hot on bumpy roads, and that heat escapes to the atmosphere. Replace the fluid damper with a magnetic one and you could generate electricity with it. The only reason nobody's done it yet is that the returned electricity would be really small. But someday the value of that returned energy will go up and then it will make sense.

Best example of a good use of wasted energy is a self winding watch. While you play you store energy in it. Maybe you could rent yourself out as a watch winder and save the planet from all those nasty little watch batteries!

[Rick Auricchio]

Originally Posted by grisezd

...Think about a car's shock absorbers...The only reason nobody's done it yet is that the returned electricity would be really small. But someday the value of that returned energy will go up and then it will make sense.

The value of that energy might be high, but the amount generated is unlikely to be any more than it is today. Maybe technology could bump the amount. Enough to run your iPod in the car? Perhaps.

[R. Laevinus]

The only halfway reasonable application I can think of is as follows:

Use a 'generator' pup to trickle charge a cap or bank of caps. When it's full (may take weeks depending on how much and how hard you play, as well as capacity of the bank), dump that power into a central storage battery, like in your house or car. Many such energy reclamation devices could be used in tandem, all dumping power into a storage battery, so that once a year, you could go a week without paying for electricity, or sell it to the grid - make yourself a tidy ten bucks a year off this thing.

Energy reclamation is a sound concept. It's a great idea, really. But in this application, I'd say the the energy cost of making and installing such a device would not be paid off by it's use for decades, if ever.

[Rick Auricchio]

My idea was micro-turbines in the sewer line. Generate some power every time you flush.

[gumtownbassman]

this reminds me of when i was a young boy and came up with an idea of installing many lamp dynamos to my bicycle and an electric motor which drove the bike wheels power from the dynamos.

Perpetual motion...

a novel idea, but nothing is 100% efficient, and with every action, there is a reaction.

Try shorting out your pickups and see what that does the the sustain of the strings.

[bassmanjla]

I think that this has a really cool use though..

so bassically, if you run a circuit of your signal after your onboard preamp boosts the signal and into a dc converter, you would be able to run into your LED's. IF the signal isn't hotter enough you could run a signal booster on that circuit to throw alittle more power, and thusly- more bright and responsive.
whats more, you could probably even put some of variable gate on the circuit so that the LEDs would pop on and off instead of fading in and out as the signal decays.

another idea... what about taking the circuit for a tuner, and using that control you LEDs? maybe you could get youfretboard to make different designs or patterns based off of what notes you were playing? Or even better... a programmable controller, so you could have different light shows plans depending on the song your playing.

my brain.... is hard to stop.. .

[line6man]

Originally Posted by bassmanjla

if you run a circuit of your signal after your onboard preamp boosts the signal and into a dc converter

Even though the preamp only draws a milliamp or two, using any sort of active component not powered by the pickup would negate the effect of the power generation.

The idea here is to create a steady DC power source from a pickup.
If you are using 9V batteries in order to do that, well, what's the point of doing it if you could have used the batteries in the first place.

[Colledge123]

i haven't done any research on this... but my last a-level physics module was mostly electricity. the way i see it is that pickups are built to produce quality... not quantity. i imagine the electricity is very... very low power. it'll be ac so you need to use a diode to convert to dc (half the power lost right there) and you'd need a transformer to bump up the voltage to whatever the preamp needs. the power that you'd draw from pickups would be so small, i'd consider other methods. maybe something like one of those shaky torch mechanisms built into the bass body so as you act like a prat on stage, a battery or capacitor gets charged up.

[guroove]

Originally Posted by St Drogo

But couldn't this power be used to, I don't know, power an active bass?

By definition, if you are using the electricity generated by the pickups, then it is a passive bass. This is exactly how a passive bass works. Using it to power the LEDs will just suck volume from your tone. You are better off trying to convert the heat energy emitted from your body like they did in the matrix.

[line6man]

Originally Posted by Colledge123

i haven't done any research on this... but my last a-level physics module was mostly electricity. the way i see it is that pickups are built to produce quality... not quantity. i imagine the electricity is very... very low power. it'll be ac so you need to use a diode to convert to dc (half the power lost right there) and you'd need a transformer to bump up the voltage to whatever the preamp needs. the power that you'd draw from pickups would be so small, i'd consider other methods. maybe something like one of those shaky torch mechanisms built into the bass body so as you act like a prat on stage, a battery or capacitor gets charged up.

A single diode would only provide for half-wave rectification.
You would want a bridge of four diodes for full-wave rectification.
And yes, depending on the forward voltage drop of the diodes, you are going to loose some voltage from the diodes alone.
After the diode bridge, you would need a capacitor to help regulate the voltage, and then depending on how clean the DC needs to be, you may want to further filter it to smooth out the ripple.

If a step up transformer is going to be used, it would have to go before the rectification, as a transformer would simply block out DC.

But I was thinking about something...
We have an AC input, and a DC output is needed, so why not try a cascade voltage multiplier circuit?
You could use a series of diodes and capacitors to transform the low AC voltage to a higher DC voltage.