That would at least get me one pulse once in a while. Thanks for the hint about Clippar, I really need to replace the homemade fast valve I have because that started to fail.
-- Regards, Joerg http://www.analogconsultants.com/
Interesting, thanks, maybe the auto parts store is part of the solution. But that still doesn't rid me of that loud compressor IIUC.
[...]-- Regards, Joerg http://www.analogconsultants.com/
Motor-driven bellows has considerable mechanical advantage. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Have you considered buying an airbrush compressor? They're pretty quiet. Michaels has good ones (Pasche), not sure about the ones that Harbor Fright sells (but the latter are also quite cheap).
I can't stand the rattle din from cheap oil-less compressors, they're horrible, though the oil-filled 5HP one I bought is still noisy (in a lower frequency way). Pro stuff like a scroll compressor is prohibitively expensive and needs 3-phase.
If the party balloon works but not long enough, then you can go searching the entire industrial catalog for a more robust solution.
-- Tim Wescott Control system and signal processing consulting www.wescottdesign.com
Bellows can only push but they cannot retract a large amount of air easily. Otherwise they would ne nice because the material is stronger than the surround in speakers. If there was a speaker where the surround is made out of bellows material I'd probably be all happy by now.
-- Regards, Joerg http://www.analogconsultants.com/
Ouch, that's a bit steep. I don't necesarily need industrial grade stuff, if it lasts 10h and then wears down it would be fine.
-- Regards, Joerg http://www.analogconsultants.com/
Now that could be an idea. I'd have to stagger the controls though, in a way that each one shoulders about an equal pressure differential on its surround. Because the weakness of the surround is the only real problem I have, they work for a short time and the go phhhht on me.
-- Regards, Joerg http://www.analogconsultants.com/
Afraid they are a bit too wimpy. Only 1/5th horse and such:
They won't be able to handle the volume, they are more geared towards high pressure at small volumes per minute.
The other engineer I work with has one but it's huge and about 600 miles from here.
-- Regards, Joerg http://www.analogconsultants.com/
I know you hate the noise, but why not _all_ pneumatic... compressor driving both sides of a piston (sequentially, back-and-forth).
This piston then drives another that provides your output. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
You've been asking for an arbitrary waveform generator -- but you really don't need that, if you're willing to trade off some build time for analysis time.
Get yourself a motor geared so that it'll put out about 2500 RPM (i.e.,
40Hz), and speed controlled down to DC. Stick a crank onto that, that works an intermediate rocker at the motor output speed. Put a slot in the intermediate rocker that holds a pivot to a rod that works a piston or bellows.To vary frequency, vary the speed of the motor (a honkin' big motor working in closed-loop is probably a good idea, and maybe a honkin' big flywheel to boot). To vary amplitude, move the pivot in the slot on the intermediate rocker.
You'll get a slightly distorted sine wave, but if you're careful with your geometry it shouldn't be too bad, and if I'm wrong about that then you'll be getting measurements from your reference sensor that you can use to calibrate the signal that's going into your sensor under test. Everything will be cyclical, so you can just capture an integer number of cycles and do FFT analysis without even bothering to window.
-- Tim Wescott Wescott Design Services http://www.wescottdesign.com
Yes, worst case I'll have to do that. Essentially a hacked compressor where the motor is on a VF drive. It would sort of work but unfortunately these sensors have effects that cannot really be gauged in the frequency domain. IOW where effects in them are depending on what happened right before, including some non-linearities.
But there may be hope. Our mechanical engineer saw this one, along the lines of what Phil Hobbs suggested:
This got my attention: "Field-replaceable top assembly system". So it might be "hackable".
-- Regards, Joerg http://www.analogconsultants.com/
Then I might as well stay with my current soltuion. Which works but makes a ton of noise.
-- Regards, Joerg http://www.analogconsultants.com/
Didn't you say just a few days? ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
No, I need it over and over again. Very little this year but a lot next spring. What I meant is that if a cheap solution works only for 10h or so it's ok, I can keep replacing stuff. This is a lab bench application, not for production.
-- Regards, Joerg http://www.analogconsultants.com/
So invest in better compressor. One of those huge dudes that hang on the wall in your garage ;-) ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Or build a 'compressor house' right outside - an insulated for sound box to hold the compressor but cut down the noise! ;-)
Charlie
Good idea!
Remember the sound enclosures for Flexowriter printers ?:-) ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
... and then break through walls, floors with concrete on there, across the office, to run a pressure line. SWMBO would frown :-)
-- Regards, Joerg http://www.analogconsultants.com/
I almost did that when my wife was heavily into Girl Scout award development. I was sandblasting patterns onto glasses, mugs, picture frames, etc.
My little hand-carry compressor, sitting in the kitchen, was a bit deafening ;-)
So I was going to plumb from the garage, but never got around to doing it. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
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