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Discussion Starter #1 (Edited)
Any ideas for motion similar to a pneumatic...?
But without the noise of compressor...?
And without the distracting air blast out of valves...?
 

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I have never used any pneumatics in any of my props for that reason. If you need to move something heavy and move it fast then pneumatics may be your only choice. Otherwise some kind of electric motor may work. What exactly are you wanting to do?
 

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Discussion Starter #3
I have a wiper motor pulling a cable to lift the arms on a prop but while it works and is stealth quiet it is the same every time..... Considering a prop controller of some sort to add randomness. Even go high speed and low speed at times.
Linear actuators are slow and they have a limited duty cycle.
I have been thinking servo or stepper motor.....?
 

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Any ideas for motion similar to a pneumatic...?
But without the noise of compressor...?
And without the distracting air blast out of valves...?
Just a couple of FYI's on these points. Compressor noise is not an issue if you can keep it far enough away or inside a shed or garage. As for the air noise through the valves, when setup correctly, this is a non-issue. I have built quite a few pneumatic props, there is zero air noise when they activate. Some of them have a faint "psssss" when slowly retracting to the static position but that's after the scare is complete.
 

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First - listen to J-Man he knows more about this stuff then anyone on this site. Second - go to www.frightprops.com and check out some of the motors, controllers and triggers. If you use a dual speed motor with a controller you can program it so that the motion appears random.
 

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Discussion Starter #6
Just a couple of FYI's on these points. Compressor noise is not an issue if you can keep it far enough away or inside a shed or garage. As for the air noise through the valves, when setup correctly, this is a non-issue. I have built quite a few pneumatic props, there is zero air noise when they activate. Some of them have a faint "psssss" when slowly retracting to the static position but that's after the scare is complete.
Thanks. But I am not interested in pneumatic props and yes if it’s only a single acting cylinder maybe you are getting a faint psssss.
But a dual acting cylinder that moves in and out has exhaust air blasts each action.
Plus the liability if someone gets smacked in the face with a pneumatic....?
No thanks!
 

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Discussion Starter #7
First - listen to J-Man he knows more about this stuff then anyone on this site. Second - go to www.frightprops.com and check out some of the motors, controllers and triggers. If you use a dual speed motor with a controller you can program some it so that the motions appear random.
Thanks
This is more the way I am thinking....
I have the wiper motor which is two speed and am looking at control options.....
Fright props is ok to get ideas from.... but they change big $&$ for shipping to Canada so I look elsewhere!
 

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Thanks. But I am not interested in pneumatic props and yes if it’s only a single acting cylinder maybe you are getting a faint psssss.
But a dual acting cylinder that moves in and out has exhaust air blasts each action.
Plus the liability if someone gets smacked in the face with a pneumatic....?
No thanks!
I'm not trying to talk you into pneumatics. All of my pneumatic props use double acting cylinders and there's no air "blast" on activation. My cylinders are not pressurized until triggered. There's no chance of anyone getting smacked in the face when built properly and positioned appropriately. In addition, I trigger my props remotely so I have total control. 😉
 

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Discussion Starter #9
Thanks J-man!
I have a 30 year Industrial background so I am very knowledgeable in pneumatics but never too old to learn a new trick or two....
Double acting cylinders have a 5 port valve usually.... one inlet air - two lines to cylinder - two exhaust ports.
I am curious how you achieve no pressure until activation? Spring or gravity return? Then why use double acting cylinder? Remote trigger for total control is good. Liability aside a smack in the face isn't good for anybody.... well maybe??? :unsure:
 

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Yes some of my double acting cylinders are gravity return but not all. The ones that require air pressure to return are shut off from the air supply after back in the "ready" position via a main valve. I typically use double acting cylinders for everything for two reasons, I don't like internal spring returns and the cylinder has more options for different applications. That being said, my Casa Fear Zombie has two double acting cylinders that get random air pressure from both directions when he's active and you can't hear any air noise whatsoever. With proper muffling it can be done.
 

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I have been using servo "gear boxes" from Servo City in almost all of my animated props. They take a regular servo motor and mount it in an aluminum frame and then use gears to attach the servo shaft to a separate shaft. The result is slower motion but a huge increase in torque. If you do not need high speed motion this may be an option for you. Here is a post I did awhile back that shows a prop I made using the gear boxes: Meet Mr. Skelly - a multi axis skull for a window display
 

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Discussion Starter #12
Mr Skelly is something else! Thanks for that! I will look into these servo gear boxes. Definitely more what I was looking into.....
 

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After years of using pneumatics, I am starting to move away from them for basic jumpers. Reason being is that for this Halloween I plan on having several barrels scattered throughout my driveway with multiple triggered pop ups out of the barrel, and to run that many airlines, air splices and accessories would be insane.

I am currently doing a mechanism something similar to the jumping spider mechanism you see at the Halloween stores. The jumper is attached to aluminum bar like you would for a pneumatic jumper. Instead of a pneumatic cylinder, I added a spring. At the base of the unit, I have a wiper motor, and at the very bottom is an electric solenoid latch. The latch holds the spring loaded prop in place until it's triggered.

Once the unit is triggered, the solenoid releases and the prop jumps up. After a few seconds, the wiper motor kicks on, pulls the mechanism down, is latched into the solenoid and the wiper motor returns home. You can use the park function on the wiper motor to run the motor home. On some of mine I will need to gear reduce the wiper motor, so I will use a limit switch instead to return the motor to the home position.
 

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I suspect that the original poster already knows this, but the speed of pneumatic cylinders can be controlled with a needle valve in line with the control valve.
 

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Discussion Starter #15
I suspect that the original poster already knows this, but the speed of pneumatic cylinders can be controlled with a needle valve in line with the control valve.
Yes...... I knew that but a lot may not think of it...?
A thing a lot of people don't know is that you always put the flow control (needle valve) on the exhaust side.
Controlling the exhaust air you get much better action of air cylinder etc.
 

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Heat build-up is one of the limiting factors in using a motor. Since window motors only have to operate for a few moments at a time, they can be smaller, and will have plenty of time to cool down. I don't know how long you can continuously operate them. I am sure it is affected by how much of a load it has, and also the duty-cycle. (Duty-cycle is how long it is on and how long it is off) . I would love to hear some real-world examples.

To make any examples really meaningful, you need to include the details of things like I mentioned above. A video is one way to sort of get a feel for what the motor is being asked to do. Tough, ideally, you would say something like "I measured the force needed to move my prop, and it was 2 lbs".
 

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Discussion Starter #18
cadcoke5 is right.... window motors will heat up if run continuously at full speed.
They have a lot of torque and are fairly quiet.... great for intermittent tasks.
I tested mine and it was ok on 5 volts continuous where it was warm but not hot.
I ended up going even slower using a PWM and as there is little load it is fine...
730646
 

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I had never really liked pneumatics for the same reasons you don't, the scene revealing noise. But it's hard to ignore the rock-solid reliability and ability to run in a heavy downpour without issues. There are a few things you can do to nearly eliminate the noises neither of us can stand -

  • run your compressor as far away as possible
  • run the lowest pressure you can get away with to run the prop
  • use cylinders with internal bumpers
  • use speed control mufflers on the exhaust ports of your valve
  • run the valve remotely
  • time your soundtrack to mask any remaining sound
I have my valve in a weatherproof box along with the prop controller behind a tombstone located about 50ft away from the prop. My supply compressor is 50ft further back. With mufflers on the valve, the vale in a box, and the box 50ft away, all of the air noises are too faint to be heard over ambient crowd noise or sounds. The cylinder rod noise is pretty easy to either mask or integrate with the soundtrack of the prop. The only downside to this is that you have to run dual lines to your prop if you're using a double-acting cylinder.
 

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I looked into this for my Zombie fence shaker and concluded that if you want to move something heavy and move it fast, pneumatics are the way to go. I resisted becasue everything else I have is electronic, but kept coming back to pneumatics. I have my compressor set up around the side of the house (with haunt in the front) and a 50 foot hose. You can' even hear it. YMMV.
 
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