Power (electricity) from playing?

[line6man]

Ok guys, just for the hell of it, I hooked up one of my basses to an oscilloscope to see what you would be dealing with as far as the waveform goes.

Jazz bass bridge pickup through 500K controls, turned all the way up. Nothing too unusual about that.

Open E string:

12th fret (fretless, btw) A string, played loudly:

5th fret D string:

50mV/Div, btw.

As you can see from just these three samples, there is quite a bit of variation in amplitude and frequency in the signal produced by a bass. Not only that, but the positive and negative phases of each cycle are not always symmetrical either.

I think it would be real tough to rectify/regulate/filter that to a smooth flat line across the scope...
Especially when you stop playing the bass...

 

[St Drogo]

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.. .

I'm not familiar with these signals boosters you mention, but it would seem to me to add power to a signal, you'd have to have an external powersource. This would of course completely negate the idea of what we're trying to do here, which is harness the electricity we create by playing. If these signal boosters don't use an external power source to function, could you maybe explain how these work?

That tuner circuit idea you mention is really cool though, goes a bit further. I like it.

(...)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.

This idea gets thrown around here a lot, and it sounds like it should be feasible. in this case, you may not even need a second "generator" pu, as the normal pu would power this capacitor during normal play.There may be a lot of uses for this, like someone mentioned an active bass that you could use the built up capacitor power when you battery had run out to just finish the set or something. Maybe there are some other uses, it's worth exporing.

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.

This would not mean it can't be implemented in an active bass, because as far as I know, the vast majority of active basses are built using passive pu's coupled with a preamp. your criticism would be grounded when you're talking about a bass with actual active pickups next to the preamp.

(...)Using it to power the LEDs will just suck volume from your tone.

This is a concern. I'm not sure what the consequences would be tonally if you siphon off a bit of the signal to power something. Might be negligible though, and if it's not, maybe you could get overpowered pu's? Like have these really hot pu's when you only want a low output vintage tone or something. the surplus of the signal could be used for other purposes without hurting your tone.

BTW, Line6man, I really appreciate the time you take for this. I mean, actually running your bass through an oscillator? <EDIT: Oscilloscope, 'scuse me> That's just plain cool, man. Though I must admit a lot of what you say goes over my head, kudos.

 

[line6man]

BTW, Line6man, I really appreciate the time you take for this. I mean, actually running your bass through an oscillator? <EDIT: Oscilloscope, 'scuse me> That's just plain cool, man. Though I must admit a lot of what you say goes over my head, kudos.

No problem, it only took me a couple of minutes.
I have a guitar cable in the cable bin with one side cut off and stripped back. All I had to do was clip on the scope probe and grab a bass and my camera.

 

[slyjoe]

...

As you can see from just these three samples, there is quite a bit of variation in amplitude and frequency in the signal produced by a bass. Not only that, but the positive and negative phases of each cycle are not always symmetrical either.

...

Now wait for the speaker clipping guys to claim that means you have DC to your speakers and that will ruin them

 

[mongo2]

This thread tickles my electronic engineer funny bone.

 

[Rick Auricchio]

Now wait for the speaker clipping guys to claim that means you have DC to your speakers and that will ruin them

Just because the waveform is not symmetrical doesn't mean there's a DC offset. There isn't. Two different things.

 

[bassmanjla]

I'm not familiar with these signals boosters you mention, but it would seem to me to add power to a signal, you'd have to have an external powersource. This would of course completely negate the idea of what we're trying to do here, which is harness the electricity we create by playing. If these signal boosters don't use an external power source to function, could you maybe explain how these work?

That tuner circuit idea you mention is really cool though, goes a bit further. I like it.



.

yah i kinda said screw the whole "generating power" part as my mind wandered with the idea. just cool ideas for things to do with the signal that are not normally done.

and dude.. an oscilliscope?!?!??! holy frakk.. that is cool to see.

 

[line6man]

Now wait for the speaker clipping guys to claim that means you have DC to your speakers and that will ruin them

DC offset can damage your speakers, but these waveforms do not have DC offset.

As Rick Auricchio said, just because the positive and negative cycles are not symmetrical, that does not mean they have DC offset.

DC offset would be when the center of a waveform is above or below zero volts.

Here is an example of positive offset (top), no offset (middle), and negative offset (bottom).
The horizontal line in the middle of the display is zero volts.

 

[slyjoe]

It was (supposed to be) a joke guys. I was parroting the misunderstanding of some of the guys that talk about clipping/DC/offsets in the amps forum. For the record, I'm a EE. I guess it was more humorous in my mind than on this page.

 

[walterw]

"NERRDDS!!!"

 

[ehque]

Doesn't the Redeemer claim to run off the trickle charge from the pickups?

Well at least the old one did, it seems the new ones are active.

 

[walterw]

never heard that one, it was always an active system AFAIK.

remember, that slight voltage output is your signal, so anything that "used" part of it would be by definition sucking away tone.

 

[St Drogo]

never heard that one, it was always an active system AFAIK.

remember, that slight voltage output is your signal, so anything that "used" part of it would be by definition sucking away tone.

Tone? Or volume? I mean, after you'd theoretically use a bit of the signal to power whatever you power, you'd run what's left of the signal through a pre- and poweramp which would amplify it. So, you make the amp work a bit harder because it has less signal to work with, is that such a problem? I mean, you can just turn it up a bit further then, can't you?

So: if you use half of the signal, obviously you'd decrease it in power, but why would the other characteristics of your tone be altered?

 

[Nedmundo]

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.

I'm with you about wasted energy. I keep thinking about hooking up an exercise bike to a large flywheel, which would keep spinning and turning a generator. I suppose it could never output more calories than you burn riding the bike, but it still might produce a useful amount of electricity, and you get exercise too. Hook up a bunch of these at the health club, and who knows? It could save on the electric bill.

Your shock absorber idea is good enough to have prompted a serious scholarly SAE paper on the subject, and the authors concude it's a worthwhile idea. I was looking for a description of GM's shocks that use variable magnetics, and found a link to the paper:

http://www.osti.gov/bridge/purl.cov...0473098FAE537C353?purl=/771018-ZIEK33/native/

Click on the pdf, and you'll find the paper entitled "A Preliminary Study of Energy Recovery in Vehicles by Using Regenerative Magnetic Shock Absorbers." So hey, you're in good company!

 

[walterw]

remember, that slight voltage output is your signal, so anything that "used" part of it would be by definition sucking away tone.

Tone? Or volume? I mean, after you'd theoretically use a bit of the signal to power whatever you power, you'd run what's left of the signal through a pre- and poweramp which would amplify it. So, you make the amp work a bit harder because it has less signal to work with, is that such a problem? I mean, you can just turn it up a bit further then, can't you?

So: if you use half of the signal, obviously you'd decrease it in power, but why would the other characteristics of your tone be altered?

when just going from a 500k to a 250k volume pot changes your tone, what do you think something as dramatic as using up half your signal trying to generate some sort of power is going to do?

have you ever ridden a bicycle with one of those generator things on it that uses your tire to spin a little cog, powering a headlight? it's like riding uphill the whole time! that's what would happen to your tone.

hell, now that i think about it, since generators create physical resistance against whatever moving part is used to power them, it could even cause the strings to lose sustain.

 

[St Drogo]

Good point, about the 500k pots. However I'm from Holland, so I know everything about bikes Those generator things (or dynamo's as they're called) used to be as horrid as you mention, however they haven't been for a long time. Nowadays you can hardly even notice if the thing is on or off, except for the sound they make. Hell, some newer bikes even come with dynamo's you cannot take off of your wheel. So if this pup-generator-thingymabob would be feasible (Which I'm kinda desperately and contrary to the arguments presented and all common sense holding on to, I know ) the first few ones may have those " friction" problems, if you will, in this case bleeding your tone. But with advancements in the technology, it's not beyond reason to think that's just another hurdle that will get jumped eventually.

As of yet however, you and others who bring the same argument, have an annoyingly sound point.

 

[Munjibunga]

Man, it'd be so cool if you could just use all that power to run your amp ... kind of like perpetual motion. All's we have to do is develop an amp that will run on a couple nano-amps of current.

 

[Nic.]

Does anyone happen to know the signal voltage and current of a crystal radio? How does this compare to the pickup signal voltage and current?

Would it be possible to rig up some sort of practice headphone "amp" that runs on the signal alone? Perhaps in conjunction with a piezo to eat up stray vibrations from the body/bridge and put it to good use.

 

[electroken]

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.

The thread could have stopped right here.

Unless you can fit a flux capacitor in your bass.

 

[David Jayne]

Neat idea, but you'd be FAR better off harnessing the wasted energy of all that foot tapping. I'm sure the potential wattage there is far greater. Piezo shoe soles, anyone?