Driving Springs for a Mechanic "Drum Module"

Ruebezahl

Hello

Some Friends and myself currently working on a Drum Machine, where the Sequencing is done in the classic electronic way, but the drum voices are generated in a mechanical way. they will use solenoids for hitting on different objects, but i actually have another plan:

Recently was playing around alot with Springs. Glued to a Contact Mic they make nice spacelike Sounds. For this project i plan to stretch them out between two surfaces. i want to send short pulse-like signals through them, and on the other end pick them up with those contact mics. The springs are 3,5cm in diameter and fit perfectly on regular size piezos. I plan to make the distance changeable and also the spring accesible so i can play around with it while the sequencer is triggering it.

So the biggest question is how to make them vibrate? I selected several options, and their drawback, if i know about them:

1. Use Piezos as Drivers:
As far as i am informed driving the springs with a piezo would need a high voltage signal with a low current, made possible by a transformer. I fear this could set the spring on a high voltage, and it could be dangerour to touch it.

2.Transducer/Old Speaker
I read about those transducers wich you put on a surface and it begins to play your sounds. i also read that you can just use an old speaker for this. looks like a strong solution, able to vibrate my spring enough. Although i fear it could be a bit heavy and big. Not as light as a piezo for example.

3.Coil/Electromagnet
I read about Spring reverbs and how they use Coils to drive the springs. I didnt work with coils yet, but maybe this is an option. I jsut dont know how to set them up. Should they touch the spring or put as close as possible?

4.Motor
I could use an Vibrating Motor like used in a mobile phone. They are able to make the Mobile Phone vibrate quiet a bit, and it should be easy to set up. Any drawbacks? maybe they are a bit small, so its hard to attach the spring, but there should be a solution for this.

I am looking forward to your Ideas/Suggestions.

PS: We plan to trigger the modules with an Arduino, so 5V if this might be important.

LFLab · Posted: Sun Nov 30, 2014 11:56 am Post subject:

You can isolate the springs from the drive signals on the piezo's,you need to, else you create a short. You do not need high voltage to drive them, BTW.
Dedicated transducers, check out the "ghost driver" on eBay, still want to check this out to create a plate reverb.

Vidsonix Ghost Transducer

commathe · Posted: Sun Nov 30, 2014 6:53 pm Post subject:

Can you tell me a bit more about how you are using the solenoids and stuff? I've actually been trying to do the same thing but I'm getting pretty lost. I've never worked with motors/solenoids or anything like that so I have no idea how to do it.

Ruebezahl · Posted: Mon Dec 01, 2014 9:53 am Post subject:

Hey guys thanks for the answers.

I just bought a vibramotor, like they are used in mobile phones. they are pretty strong with low Voltage and they have the advantage that i dont have to feed them wave-signals, i just gate the power-supply. the drawback is that you can almost not controll the wavelength,. I will se how it will work out.

@commathe hey we are still around trying things. the problem with the solenoids is that they need very high Current to work, so you need a Power Supply wich can give enough Current out, especially if you want to power more than one at a time. we will probably trigger them through an octocoppler, to not bring the arduino in danger (we already crashed two of them Wink

). What are you planing now? Motors and Solenoids have different problems and also different ways to work. We use the solenoids to hit different objects and the motors to vibrate objects, in this case a spring.

commathe · Posted: Mon Dec 01, 2014 8:42 pm Post subject:

I pretty much have only looked at solenoids. Both rotary and push-pull types. I'm only really interested in hitting things. Cool

DUBmatze · Posted: Tue Dec 02, 2014 12:32 pm Post subject:

the first thing i thinking about when reading this is a central locking control unit motor. if you stretch the spring with it iam shure it make a percusive sound. They running on 12Vs. A set of 4 is about 20€ on ebay.

Ruebezahl · Posted: Mon Dec 08, 2014 7:56 pm Post subject:

Hey DUBmatze,

That sounds interesting. I couldn't find anything with the search term "central locking control unit motor" though? Is it the thing wich puts the knobs at car doors up and down? Maybe you have a link for me?

I tried a Vibramotor for Cellphones but i am not satisfied. It vibrates quite a lot, but it doesnt really sound percusive. the attack is not sharp enough.

DUBmatze · Posted: Wed Dec 10, 2014 9:12 am Post subject:

here you can buy that:
http://www.ebay.de/itm/Universal-ZV-Zentralverriegelung-Stellmotor-Funkfernbedienung-FFB-Fernbedienung-/131008845453?pt=DE_Autoteile&hash=item1e80bc568d

maybe this can help while develop a driver circuit:
http://homemadecircuitsandschematics.blogspot.de/2011/12/build-homemade-gsm-car-security-system.html

i have seen videos on Youtube with natural drumkits (Snares, Toms, Hihat) that use this motors - so it must be possible .... Wink

Ruebezahl · Posted: Tue Dec 16, 2014 2:50 am Post subject:

Thanks. It looks interesting, but by now i already came to the conculsion that i want to pluck the springs rather than push/pull them. I found a video where the motors does pretty much what i want. i dont know how he did it, however. iw rote him a message, and i wait for his answer.

http://www.matrixsynth.com/2012/07/lunetta-guitar-vco-test.html

Anybody else does have idea how to let motors do this "snap back"-thing?

DUBmatze · Posted: Tue Dec 16, 2014 5:25 am Post subject:

mhm ... you can hack a servo motor for endless rotation and attach a pice of windscreen wiper rubber to it.
( http://www.instructables.com/id/How-to-hack-a-servo-for-continuous-rotation-Towe/?lang=de )

or just a cheap taperecorder motor: http://www.pollin.de/shop/dt/MDY5OTkxOTk-/Bauelemente_Bauteile/Sortimente/Mechanische_Bauteile/Kassettenrecorder_Motoren.html
?