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Uncle Krunkus
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Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
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Posted: Sat Oct 15, 2005 4:36 am Post subject:
I want to build a Mechatride |
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I found an old ride cymbal and I'm thinking of building a robotic electro-acoustic instrument. It starts with a simple sequencer based around a CD4017 (or 2 of them cascaded to make 16 steps) then this series of pulses is used to fire a push type solenoid, which is mounted under the ride cymbal. The solenoid I'm looking at is rated at 220-940gm, 25R6 coil resistance, 20watt@25%duty.
Eventually I'd like 2 microphones mounted under it so I could record it in stereo, and at least 2 extra solenoids with their own sequence pattern programmable (switches) and then I'll work out how to clock it from a midi source.
But for now I'm wondering what anyone might suggest as the CMOS to Coil circuit.
Thanks in advance to anyone who might be able to help.
Andrew _________________ What makes a space ours, is what we put there, and what we do there. |
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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Posted: Sat Oct 15, 2005 5:03 am Post subject:
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Maybe one of those "modern" solid state switch thingies, they deal with short circuiting, over heating (and other nasty stuff) for you, don't cost too much anymore and can be controlled by a "logic signal".
Over the last years I've seen those being used in almost all hardware that I have to write programs for. Sorry to not have any type ID's ready for you but MAXIM would be a good place to look for 'm, I suppose. _________________ Jan
also .. could someone please turn down the thermostat a bit.
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mosc
Site Admin
Joined: Jan 31, 2003 Posts: 18197 Location: Durham, NC
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Posted: Sat Oct 15, 2005 8:00 am Post subject:
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Good suggestion, Jan. These are great and easy to use. I suggest you get them with opto-isolators built in. Then you have less chance of frying your logic circuits with contact to the AC, and you can keep the grounds (Earths) separate. You can also get some that only turn on at zero corssings of the AC waveform. This will keep them from making a lot of interference that might get into your audio. Conventional relays can be very noisey electrically, as well as acoustically. _________________ --Howard
my music and other stuff |
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Uncle Krunkus
Moderator
Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
Audio files: 52
G2 patch files: 1
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Posted: Sat Oct 15, 2005 8:40 am Post subject:
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I can get this one,
http://www.jaycar.com.au/products_uploaded/SY-4080.pdf
for AU$12 which is pretty good as the solenoid is AU$30.
The only thing I'm not sure about is the speed, it mentions max on/off times, but will these remain consistent when the speed of triggers changes? I s'pose I should just try it out and see. Your point about keeping noise out of my audio power rails is a good one Mosc. That's why I didn't want a conventional relay. I thought I'd need some elaborate MOSFET circuit etc. but this does look worth checking out. _________________ What makes a space ours, is what we put there, and what we do there. |
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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Posted: Sat Oct 15, 2005 8:56 am Post subject:
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Howard mentioned AC, I was thinking DC though (24 V I guess from the specs you gave for the solenoid).
DC will add some cost for a power supply (no need for regulation, but a full bridge and and a large capacitor would be needed) but DC solid state switches would be cheaper and DC would give more consistant timing I'd think.
Otoh about 10 ms timing jitter might not be too disturbing either. _________________ Jan
also .. could someone please turn down the thermostat a bit.
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Uncle Krunkus
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Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
Audio files: 52
G2 patch files: 1
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Posted: Sat Oct 15, 2005 9:12 am Post subject:
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Yeah, that one from Jaycar isn't recommended for DC though.
I need to keep the cost down. _________________ What makes a space ours, is what we put there, and what we do there. |
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Uncle Krunkus
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Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
Audio files: 52
G2 patch files: 1
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Posted: Fri Nov 11, 2005 3:22 am Post subject:
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Okay,
I've got the solenoid, but,...
I've blown my budget and have to build the interface circuit from stuff which I have lying around already. I've got lots of transistors, power supplies, etc. I'm thinking of starting with the solenoid end and working backwards. Some kind of power transistor (TIP41, MTP3055?) put it in a common emitter setup and find out what happens. I have never done much prototyping before so this should actually be a very good learning path to wander. Anyone out there with more circuit design experience than me want to throw around some ideas? _________________ What makes a space ours, is what we put there, and what we do there. |
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jksuperstar
Joined: Aug 20, 2004 Posts: 2503 Location: Denver
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Posted: Fri Nov 11, 2005 10:19 am Post subject:
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If the transistors / FETS/ MOSTFETs you have can't pull enough juice for the solenoid, you can always run a couple in parallel.
Also, MAXIM is VERY good about giving away samples in low quantities, and they have lots of "gourmet" motor drivers and other wierd chips that most manufacturers won't make due to low volumes. If you need something, hit their website http://www.maxim-ic.com, I think you have to register, then request the free samples of what you need. They even put a "click here for sample" button on each components webpage.
Otherwise, a 5v coil/24v+ relay would work easily, give you isolation, and you can stick it in a box to keep things quiet. Or you might like the click going along with the ride.
PLEASE, post pictures when you have this working! I'd like to see how you mount the drum stick (or part of it)(or whatever beater you are using). |
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Uncle Krunkus
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Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
Audio files: 52
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Posted: Fri Nov 11, 2005 9:15 pm Post subject:
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The solenoid is a push type like this .
I 'm actually planning on mounting it directly under the cymbal to minimise delay. It has a metal plunger which initially I'll leave bare. I could put a boot on it, but I'll see how much top end I get out first.
The whole thing will hang on the wall like a piece of flat wall sculpture. The solid back plate should improve top end. (11Khz has a wavelength of about 30mm) I'll keep this adjustable of course, and the mics will go through a stereo parametric EQ of some kind to increase flexibility.
The only cables going up the wall to it will be the power, a midi clock and of course the stereo output coming back down.
[note, compacted the URL to narrow the page a bit, Blue Hell] |
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