Xylophone

[bill]

Hello,

I woud like to (try to) build a midified percussion organ (xylophone like),

so, i need some kind of solenoids to drive the sticks.

I think i'm capable of doing it (seems pretty simple) but, i have no idea where to get those "percussion engines"

Any tips for this ?

Thanks :)

[Screaming_Rabbit]

... in any Surplus Stores

or here: http://www.rapidonline.com/netalogue/specs/60-3205e.pdf

[pay_c]

RS and Farnell have some, too (http://www.rsonline.de http://www.farnell.com/). You should get them in pretty many places. Just search for Solenoid, that should be it.

[nILS]

pollin.de has some. Since you're from France, that should work shipping-wise as well.

[Sasha]

I was interested in this for a long time. I did something similar by mounting small toothpick with beater on relay lever. That was just for testing, These beaters on video seamed just right. I wasn`t sure which one to get and where from. I also bought rusty xylophone on flea market. :)

[TheAncientOne]

I think he's driving it with Pure:Data, which can be downloaded for free, though can be a bit of a handful on small machines. It's in the Pure:dyne 'boot from the CD' Linux too. Juts how big a monitor had he got??

You can drive eight of those solenoids from a simple parallel port interface, though you'll need a driver chip, or transistors, and an external supply.

[Sasha]

You can drive eight of those solenoids from a simple parallel port interface, though you'll need a driver chip, or transistors, and an external supply.

Mike, why drive the solenoids from parallel port with pure data using transistors or better ULN2803 when you can hook it on DOUT and have all benefits of MIDI coming from any midi soft rhythm machine or better from MBSEQ. I tried mine relay on MB64 with midi feedback script added to Ableton Live, and it worked great! Only thing is the relay is not the best for this job, better something simpler like those from the video. I found exactly like those from video at Farnell as Pay_c pointed but they are pretty expensive if you need alot of it. I was thinking about making it myself. Does somebody knows some formula for calculating wire diameter and number of turns in coil for making solenoids. I was making some as a kid but without any calculations. It worked but they surely wasn`t optimal.

[TheAncientOne]

I was thinking of a quite and dirty solution like his. A midi xylophone is a way better idea.

If you were going that route, then the solenoid circuit might be worth doing some more work on. By using 2 DOUT's per solenoid, and a charged capacitor, you could get more than one level of strike, so emphasis would be possible. Something similar was used in line printers to 'fire' the hammers. I'll have a think. Normal current for a soft 'hit', fire the charged cap as well for a harder one. You're still going to need your transistors or ULN's - Solenoid current will fry a CMOS output stage, so an old PC with a little player program would make a good test rig, (even a 386 would do this, so a pc out of a skip would help you get the mech going).

Solenoids are a pain to make. The plunger needs to be the right type of soft iron, or it will magnetise over time. then you need spools, miles of wire and a winding jig. Been there, done it, and still have a few scars, (helping restore a fairground organ, in pre MIDI days). There must be something that you could salvage for the job. I think you were very much on the right track with your relays with an extended arm. The old UK 'post office', (telephone), type would be ideal as they are very robust and reliable.

By the way has anyone posted this before? Note the relays....

[bill]

Thank you all for the tips ! :)

RS and Farnell have some, You should get them in pretty many places. Just search for Solenoid, that should be it.

yes, i've seen them, unfortunately, they dont have those cheap and small ones i need, those ones are good to lock a car door or that kind of stuff ;) (they are too big)

If you were going that route, then the solenoid circuit might be worth doing some more work on.

yep, i know that's a bit of work there, but i did that in the past.

i know i need ULN2003A transistors network (or equivalent) to boost the douts, before attacking some relays, self protecteds by "free wheel" diodes preventing the "impedance rupture".

In fact, I have the "power" board ready yet ;)

Atm, i'm just in a quest of the "perfect solenoid" ^^

I cant wait to send my MBXylophone video  ;D

[Jaicen]

Is it just me, or do those solenoids sound pretty noisy on their own?? I'm pretty sure that the click would be audible ooperating on something like a xylophone.

Maybe you could look for something hydraulic??

[Sasha]

They can be silenced. ;)

[DrBunsen]

By using 2 DOUT's per solenoid, and a charged capacitor, you could get more than one level of strike, so emphasis would be possible.

Or a 2-bit AOUT_LC  ;D