AC motor to turn reels for a theater prop camera?

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Old 03-18-15, 09:11 PM
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AC motor to turn reels for a theater prop camera?

Hey all - first, you all have truly made this the most helpful forum on the internet. This site is amazing - thank you!!!

Weird project! GF is directing the musical Willy Wonka, and part of the set construction is the WonkaVision Camera, which should look something like this (ours will look a bit different, but it's the same basic idea.)



Except that when the kid hits the button he's not supposed to hit, turning on the camera and beaming him inside the TV, it's supposed to be pretty dramatic. Thus, we'd like the reels to turn and I'll also put a red light on it.

Sooo...I am looking for a motor that can turn the two reels on top. 120v would be great so it can just be switched on at the right time (along with the 120v light.) I've found a few links to low-RPM motors online, but really have no idea what I'm looking at, nor any knowledge of how to link it to the reels (bicycle chain? gears? But how to attach the gears?)...so I'm afraid without your sage advice I am but an empty hole.

Any chance you all might be able to save the day? I saw somewhere that a windshield wiper motor might work, but would it run the same direction? And how to interface it with the reels?

Many, many thanks, all!
 
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Old 03-18-15, 09:50 PM
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Have a slot for the real in the top of the camers so that the botom of tre real is perhaps half an inch below the top of the camera. A rubber roller on the motor shaft would spin against the bottom of the reel. Note this method would reduce the speed of the reals by a factor of perhaps 10 if the motor roller was 2" or less..
 
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Old 03-19-15, 05:13 AM
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I have had good luck with Surplus Center. They carry an every changing array of motors and bits. Below is a link to the AC gearmotor part of their website. They currently have several small and cheap AC gearmotors that could drive the reels of the projector.

Surplus Center
 
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Old 03-19-15, 09:33 AM
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Another possibility would be to scavenge the workings from a console room humidifier. Those have an AC motor driving a couple pulleys/belts to reduce the speed of the roller that spins the big wet drum. Thrift store $10 item...or donated by someone in the theater crew...

Looks like you have a lot of room inside that "camera" case.
 
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Old 03-19-15, 09:38 AM
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Proofing my post the word "console" led me to another idea: An old turntable mounted on its side with a pulley glued to the platter or the "reels" sitting directly on the platter rim. You would have the option of 16, 33, 45 or 78rpm if it's old enough :-)
 
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Old 03-19-15, 08:23 PM
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You guys are the best!! Thank you so much. I also wondered about a turntable, but I seem to recall from many years ago that it was relatively easy to stop the turntable with just a finger; this makes me wonder if it's got enough torque to turn two poorly and cheaply designed reels!

Sooo....from the Surplus Center site, here's a 135-RPM motor for all of $5.99...seems that might just do the trick. It appears to have a hex head...might there be gears/rubber roller/anything else that might just slide over that hex head? Sorry for being such a noob at this stuff!!

Thanks again so much guys!
 
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Old 03-20-15, 04:58 AM
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I don't know where you are seeing a hex head unless I'm looking at a different motor. This is the one I'm looking at. It has a 1/4" diameter shaft with a flat spot that would be perfect for a set screw. With that motor I would say you have two possibilities:

1. Find or make a pulley or wheel. Attach a O ring or rubber band to the outer circumference of the wheel for traction and mount the motor so the wheel pushes against the outer edge of your camera reel. You would need one motor for each reel if your want them to turn in the same direction but if you put the motor between the reels (which would probably be visible and hurt the appearance) each reel would turn in opposite directions.

2. Buy or make a pulley to go on the motor's shaft. Mount the motor down in the camera body out of sight and run a large O ring, belt or "rubber band" around the motor pulley and around your reels either on their outer circumference or on their inner hub.

In either case a online search for "small motor drive belt" or "small motor pulley" will turn up many retailers. Here is one of the first I found. I have never ordered from them but they have a lightweight set screw hub that could go on the motor's shaft. Then on that they sell different size and style pulleys that you screw onto the hub and they also offer drive belts.

I keep mentioning belts because they can be clean and safe. A belt running on a smooth pulley can be set to have enough power to turn the reels but will slip if someone grabs or bumps into them. While a belt can pinch if your stick your finger in the wrong spot the light tension you'd need to drive your reels means the belt could be quite loose and present a minimal hazard.
 
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Old 03-20-15, 05:32 AM
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To add with pulleys the belt can be as simple as a large heavy duty rubber band. I have made pulleys using plywood or hard board and a hole saw. Cut two discs using a hole saw. Cut a smaller disk using a smaller hole saw. Sandwich the small disk between the two larger disks and glue. Use a " bolt to align and hold the disks till they dry.
 
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Old 03-20-15, 05:37 AM
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Originally Posted by theTastyCat

You guys are the best!! Thank you so much. I also wondered about a turntable, but I seem to recall from many years ago that it was relatively easy to stop the turntable with just a finger; this makes me wonder if it's got enough torque to turn two poorly and cheaply designed reels!
The kind of TT I'm thinking about is an old "rim-drive" where a rubber tire drives the platter from underneath. They have gobs of torque and are hard to stop with a hand. Most players, from kiddie portables to large consoles from the 70's and older used this kind of drive.
All newer belt drive and most direct-drive TTs are weaker. The old relics have another advantage in that the platter is held on by a C-clip so it will run on its side.
 
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