I have a question regarding an idea I had.
Is it possible to control strong electro magnets with great speed? I want to build a music instrument (like a xylophone). I want to place a permanent magnet inside the piece of wood, 1mm under that piece of wood I want to place the controlled electro magnet.
Do think electro magnet are quick enough for frequencies around 50-200Hz? It is similar to a normal speaker, right? But a piece of wood is very different to a very light speaker.
You can certainly switch the current on and off that quickly. How much current and what voltage were you thinking? You can probably use a logic level MOSFET.
But what do you expect to happen when you do this?
Speed is not your problem, it's power. You either need a high voltage to force a quick movement, or high current, depending on the impedance of the system and the mass (inertia) to move.
It's not clear to me, what you want to make move or vibrate.
I have a question regarding an idea I had.
Is it possible to control strong electro magnets with great speed? I want to build a music instrument (like a xylophone). I want to place a permanent magnet inside the piece of wood, 1mm under that piece of wood I want to place the controlled electro magnet.
Do think electro magnet are quick enough for frequencies around 50-200Hz? It is similar to a normal speaker, right? But a piece of wood is very different to a very light speaker.
Thanks a lot!
Just a note that this is an absolutely fantastic idea and that I encourage you in the strongest possible terms to do this!! It'll be awesome :-D. And there is literally no way you can't get this to work. Did I understand that you're getting something to hit it from underneath (against the force of gravity)?
Why do you feel that this needs to be controlled with great speed? A human xylophone player plays quite slowly by electronic standards so where does your 50-200 Hz requirement come from?
an electromagnet is only part of a solenoid. a solenoid has a section insdie of the magnetic field that moves.
by creating the field and allowing it to collapse, you can create movement of said piece. this is what a microphone is.
the larger object you want to move the more power
the more power, the greater inrush
the greater inrush, the greater impedance.
what this really means is that for larger objects, you will need to have more voltage to be able to charge the coil with enough power is very short order, with a current limting circui. then you will also need to dump the energy of the coil at great haste to change the state of the coil.
look at any electric organ or piano or bells, they have such solenoids.
There are also devices you can mount on your wall and turn your wall into a speaker.
Wow, so much response, thanks a lo, great community! I am on my phone, cant write that much for now, but to make it clear, i want to build a large xylophone and play it with an arduino.... I dont want to hit the wood, I want to make the wood vibrate without touching it. I want to place a permanent magnet inside the wood... Below the wood should be the electro magnet. The 50-200hz range was just an idea... I like dark, deep drones... And since I want to make large wood elements... the will be more on the bass side...
kabelton:
Wow, so much response, thanks a lo, great community! I am on my phone, cant write that much for now, but to make it clear, i want to build a large xylophone and play it with an arduino.... I dont want to hit the wood, I want to make the wood vibrate without touching it. I want to place a permanent magnet inside the wood... Below the wood should be the electro magnet. The 50-200hz range was just an idea... I like dark, deep drones... And since I want to make large wood elements... the will be more on the bass side...
If those are your vibrational frequencies, think more about planks. A resonanant chamber to make something like that audible, would also be huge. Think about when the last time you saw a bass xylophone was.
kabelton:
Wow, so much response, thanks a lo, great community! I am on my phone, cant write that much for now, but to make it clear, i want to build a large xylophone and play it with an arduino.... I dont want to hit the wood, I want to make the wood vibrate without touching it. I want to place a permanent magnet inside the wood... Below the wood should be the electro magnet. The 50-200hz range was just an idea... I like dark, deep drones... And since I want to make large wood elements... the will be more on the bass side...
hmmm, have you seen this work before? how do you know that vibrating wood in this way works? (Just a question).
I thought you were hitting it, playing it like a normal xylophone and getting normal xylophone sounds out of it. You want to vibrate the wood pieces in a totally different way. How do you know that works? Just curious
I have not seen it before... I hope the wood (small permament magnet inside) vibrates with the same frequency I switsch the electro magnet on/off. I am curious how strong it should be.
kabelton:
I have not seen it before... I hope the wood (small permament magnet inside) vibrates with the same frequency I switsch the electro magnet on/off. I am curious how strong it should be.
Well, as any experienced electric bass xylophone designer, can tell you... wait. There aren't any. Perhaps you need to experiment.
A xylophone works on resonance. Each brick has its own note, which it plays after a stroke. Then a periodic excitation is not required. It's near impossible to make it produce a sound of a different frequency, unless the bricks are almost as thin and light like a loudspeaker membrane.
Try to play a single brick in the intended way, to find out yourself about the limits of your plan. If you can make it work, it should be not so hard to extend the instrument to play multiple or other tones at the same time.
aarg:
Of course you could vibrate wood. It would be like the way a bow works on a violin string.
I strongly suggest people test their assumptions by actually building a proof of concept. 5% of the time it works every time. The rest of the cases you immediately learn something very, very valuable that you can start incorporating immediately.
I think everyone agrees you should try it with one piece first and see if the sound you get is what you want. But, no matter what, you can definitely make a xylophone by hitting the bars once and letting them ring. I encourage you to try it! You can try your way too
I would switch on/off the electro magnet with a speed as the resonance frequency of my wood. With a potentiometer I can regulate the voltage from 0-24v, like a volume potentiometer.
For testing I will build something like that:
Inside the wood, in the middle and above the electro magnet (with a gab of 1mm) I will place a strong permanent magnet.
So, driving/switching a electro magnet with a motorshield can work?
I expect you will have quite a learning experience with all this.
As I understand (poorly at best) creating a resonance nearby a thing that has the same resonance frequency, you can get the thing to vibrate at the same frequency. magnets have a very short distance for their magnetic field.
as you apply power, the thing you want to vibrate, will start to vibrate and eventually vibrate at the same power as you apply from your remote thing.
the location of the magnet will be important as it will need to be placed in the section that vibrates. the further away, the more power it will take, and most likely, the longer time period before the resonance has an amplitude that creates an audible noise.
contrast to a striker that would replicate the way the device is operated manually, with instantaneous sound.
Please keep us posted, you have a fascinating project.
I hope the wood (small permament magnet inside) vibrates with the same frequency I switsch the electro magnet on/off. I am curious how strong it should be.