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Old March 20th, 2007, 07:00 PM   #1
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Motorized Cable Trolley

I've been doing quite a lot of research on cable camera systems and I've decided to build one with a budget of around $10,000, but it may take more.

This is going to be a pretty big project and any advice when I'm going through this would be appreciated.

Right now I am trying to figure out the type and size of motor I will need for the movement of the trolley up and down the cable. I've decided to use one main 3/8 cable for the support instead of two because of easier and quicker set-up times. I'm also planning on having another, maybe nylon, cable connected to the trolley on each side to pull it up and down. I will draw a diagram perhaps. As for the motor I need to find out what the torque and rpm will be

I'll be using a 12" diameter wheel for the pulley system.

It needs to be able to go up about a 50% grade so like 45 degree angle

A max speed of about 35mph when cable is fairly flat

Carry about 50lbs max on the trolley.

I'm going to buy a wireless controlled motorized remote head to attach

I'm not sure how many of you out there are involved with using this type of setup, but I could use the help of anyone who is skilled in the RC department even or anyone who wants to help out.

Jeremy
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Old March 20th, 2007, 07:18 PM   #2
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Quote:
Originally Posted by Jeremy Teman View Post
I've been doing quite a lot of research on cable camera systems and I've decided to build one with a budget of around $10,000, but it may take more.

This is going to be a pretty big project and any advice when I'm going through this would be appreciated.

Right now I am trying to figure out the type and size of motor I will need for the movement of the trolley up and down the cable. I've decided to use one main 3/8 cable for the support instead of two because of easier and quicker set-up times. I'm also planning on having another, maybe nylon, cable connected to the trolley on each side to pull it up and down. I will draw a diagram perhaps. As for the motor I need to find out what the torque and rpm will be

I'll be using a 12" diameter wheel for the pulley system.

It needs to be able to go up about a 50% grade so like 45 degree angle

A max speed of about 35mph when cable is fairly flat

Carry about 50lbs max on the trolley.

I'm going to buy a wireless controlled motorized remote head to attach

I'm not sure how many of you out there are involved with using this type of setup, but I could use the help of anyone who is skilled in the RC department even or anyone who wants to help out.

Jeremy
Well, that does sound rather ambitious! What will it be used for? How are you going to stretch, or maintain tension on the cable?

Mike
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Old March 20th, 2007, 08:08 PM   #3
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Mostly action, sports, outdoor shots over canyons, events. Things like that.

The cable will be secured to tress or strong structures and will be anchored using steel cable anchors and winches.
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Old March 21st, 2007, 02:08 AM   #4
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you can use a cable winch found on 4x4 cars (the ones bolted on the front bumber of cars), it is very powerfull, runs on 12v, some have a remote control.
you just need to add a controller for speed and replace the cable with a thinner/longer one, and they are cheap.
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Old March 21st, 2007, 02:24 PM   #5
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If anyone has any knowledge of what type of electric motor would suit this job that would be a big help
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Old March 21st, 2007, 03:29 PM   #6
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any 12V DC motor with good multiplier would fit. you can find some for under 20$ at http://www.jameco.com/webapp/wcs/sto...egoryId=351540.
choose high torque , mid speed (30-50 RPM).
you add a small PWM controller to control speed and direction.
My opinion is you should move the cable not the camera on the cable.
a simple pulley at one end , the motor at the other end.
in case of problem, you can get you camera back, it does not stay stuck in the middle.
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Old March 21st, 2007, 03:32 PM   #7
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Sorry, I meant motor for the pulley system for the trolley going up and down the cable.
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Old March 21st, 2007, 03:39 PM   #8
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Finding a high precision motor is most likely in the $1000 range. I am thinking of having one main steel cable for the trolley to ride on and all of the movement will be controlled from another pulley system. A motor on one end, and a cable wraped around connecting to the trolley and wrapped back around to the other side. A motor able to bring this up to speeds of 30-35mph and carry about a 40-50lb trolley is what I'm trying to find.
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Old March 21st, 2007, 03:44 PM   #9
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I'm also trying to find a controller system similar to what controls a motorized head that I could set up to the motor pulling the camera. I don't want to use a RC hobby type controller.
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Old March 21st, 2007, 04:10 PM   #10
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With the weight you wish to suspend and the speed you want to move it, you will spend a good chunk of money. Fifty pounds suspended at any distance is going to put a load on the cable.

Like you mentioned, one cable to suspend then another lighter cable to move the camera would be best.

I'll check, but McMaster Carr and Grainger are great places to look. You will probably need a gear reduced motor will variable speed and it will probably in the 1 hp range, plus reversable.

Don't think you really want to do this like have have said, as it will cost a small fortune. Well into the thousands for something reliable.

A much lighter camera dolly/trolly and a less ambitious speed would seem in order.

Mike

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Old March 21st, 2007, 05:52 PM   #11
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Originally Posted by Mike Teutsch View Post
With the weight you wish to suspend and the speed you want to move it, you will spend a good chunk of money. Fifty pounds suspended at any distance is going to put a load on the cable.

Like you mentioned, one cable to suspend then another lighter cable to move the camera would be best.

I'll check, but McMaster Carr and Grainger are great places to look. You will probably need a gear reduced motor will variable speed and it will probably in the 1 hp range, plus reversable.

Don't think you really want to do this like have have said, as it will cost a small fortune. Well into the thousands for something reliable.

A much lighter camera dolly/trolly and a less ambitious speed would seem in order.

Mike

Mike
The weight on the suspended cable is not an issue, we easily can do a 1000' 200lbs man ridden zipline type setup.

Like I said our budget for this project is around $10,000, we're aware that we are in need of an expensive motor. The 50lb weight is going to be the absolute max as with the 50% grade. The weight may be closer to 20-25lbs depending on cameras used and gyro.

The speed of the trolley is an must as the objects being filmed will be traveling at about that speed.

Thanks for those sites!
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Old March 21st, 2007, 05:54 PM   #12
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speed is not really a problem, acceleration is.
if you build your system with minimum friction, small motors will fit your needs for cheap, but you will not be able to start and stop at high speed or climb gig slope (45 degrees is a lot !)
you can cheat by using magnetic breaks for deceleration.
for the design of my crane, i choose the oopic controller (small processor on a board) with the magnevation controller (piggy board PWM board for 2 motors). Add a joystick and few line of code and you can drive almost any small device you want for less than 200$.
in your case you could go for a heavier PWM driver and bigger motor (like found in old big printers). You can easily build a demultiplier with 2 gear and a gear belt.
if can go lightweigth, you can even build a standalone motorized sled that run with a small cam on a cable. i am sur you can get hi-speed easily then.
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Old March 21st, 2007, 06:01 PM   #13
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Yeah, I'm going to have to find something with a high holding torque to be able to stop it on that angle with weight and powerful enough to get it moving once stopped. I do not expect it to go up a 45 degree slope with 50lbs at 35mph. Just at a decent speed. I need the fast speed at the most level point of the cable.
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Old March 21st, 2007, 09:08 PM   #14
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OK, If you really want help, why not list the real specifications you are looking to achieve.

Lengths, weights, etc..... Then we can help!

Mike
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Old March 22nd, 2007, 01:29 PM   #15
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Those basically are the specs.

I will need to to be 1000-1200' in length.

Reach speeds up to 35mph.

Be able to climb up a 50% grade, maybe not at the full speed.

Carry a max of 50lbs.
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