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 Homemade Dolly/Jib 
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Joined: Mon Mar 14, 2011 8:13 pm
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Post Homemade Dolly/Jib
Hello, I'm primarily an astrophotographer but lately I've been dabbling with Timelapses. I have fond memories of some cinematography courses I took back in community college years ago so I thought this would be a fun side project. A year ago I built a crude dolly for a trip I took into Death Valley. It worked pretty well but after watching countless timelapse videos with slider shot after slider shot I decided I wanted to try something different. I threw together a design in Solidworks (which I am still a big amateur at) and got to work in my garage. Its been challenging as I live in an apartment and do not have any electrical outlets so I was limited to my cordless drill and a hacksaw. I was able to get one part made by my friend who has a CNC mill at his work so that was a huge help.

Here are the Solidworks sketches and renders:
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Assembly.

I don't have the ability to weld aluminum but I figure if this adhesive is good enough to hold body components on modern cars together then I'll be okay.
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Initial design had the motor mounted directly on the carriage. This was deemed too heavy and took up a lot of real estate I needed to mount my Jib on.
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The carriage is an aluminum base with two pieces of carbon fiber plate sandwiching a 1/4" piece of pine. Yes, the cuts aren't great but again, hacksaw and low budget.
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Starting work on the jib arm. The arm is sandwhiched between some nice needle thrust bearings which lets me get things nice and snug but with very little friction on the arm itself allowing for smooth motor movement.
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Baseplate shown. The whole thing is sitting on a roller bearing (like a wheel bearing on a car), this lets me put a bunch of weight on the baseplate without compromising fluidity of motion.
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Initial mounting to the dolly
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Got most of the parts covered in some black self etching primer, once its complete I will likely spray it with some nice matte black truck bed liner (I work in the autobody industry so this part is simple)
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The whole jib pieces comes off with four thumbscrews so if I just want a sliding pan I don't have to set the jib up.
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So thats the assembly. I should probably take more pictures.

As you can see I opted to use stepper motors. Not because they were necessarily the best choice (dc motors + encoders would be ideal) but because they were the simplest to get working. I am using an Arduino Mega for control. Motors are driven by a few Big Easy Drivers.

Initial breadboarding:
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Pre-wiring:
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And the wiring. I went for panel mount components because they were the simplest for me. I have zero experience with electrical engineering so I just went with what seemed within my abilities yet still solid enough to work fine in the field.

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Controls:
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I will have a total of five axis to move. From top to bottom, dolly, jib arm, jib rotate, camera pan, camera tilt. I have not yet added the mechanics for the camera pan/tilt yet but the electronics are all there so once I do build the parts all I need to do is plug in.

Each axis will have four controls. Bottom button is to set motor direction, big red pushbutton is start/stop, first potentiometer controls speed and the top empty holes are for another pushbutton that will act as a radio button to bring up that axis information on the LCD.

On the top of the controller (next to the LCD) is a master start/stop button and a master speed potentiometer. The master speed pot simply multiplies whatever the motor speeds are for each axis uniformly. This lets me preview my shot. If I just set everything up for a typical astro timelapse I'd have no idea how the speed of one axis will relate with the speed of another axis since the movement will take place over the course of eight hours. The speed multiplier lets me condense the whole action into 60 seconds or so which will eliminate the guesswork out of setting the controls.

I really couldn't find any good examples of code for this so I had to re-learn to code (I used to dabble in PHP and Java years and years ago) and figure everything out. I gotta say, Arduninos make projects like this a dream. The coding part ended up being much simpler than I expected as I was dreading it during the construction phase.

I've done some testing in my garage and everything is working as expected. I will do some basic tests this weekend to figure out power usage and stability. Next month I will likely head out to Anza Borrego for the weekend and in October I plan on visiting some remote areas of Death Valley and the White Mountains to capture footage.

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Thu Sep 04, 2014 8:08 pm
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Joined: Mon Nov 22, 2010 1:18 pm
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Post Re: Homemade Dolly/Jib
Good to see somebody building something other than a slider :D
Look forward to seeing some footage if you get a chance look at Dragonframe or Mantis if you ever want to key frame etc.
Suggest you take somebody with you when you go on your field trip . The problem with more complex rigs is it take alot longer to get yourself set up .
It as become apparent i never leave my shed these days :(


Fri Sep 05, 2014 3:38 am
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Joined: Mon Mar 14, 2011 8:13 pm
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Post Re: Homemade Dolly/Jib
Setup doesn't bother me, again I'm an astrophotographer without an observatory, setup in the field usually takes two hours or so and I do it at least twice a month. Even with this level of complexity setup should take maybe 20-30 minutes and once its running I won't have to babysit it.

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Fri Sep 05, 2014 8:25 am
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Post Re: Homemade Dolly/Jib
That's great wish i was that well organised . Post some stuff when its in the can .
D1


Fri Sep 05, 2014 1:02 pm
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Location: Merritt Island, Florida, Estates Unitas
Post Re: Homemade Dolly/Jib
Nice build! I like the idea of using the car wheel bearing for the crane base pivot. Its obviously going to be robust enough for the job, and the mass production of them means they are probably cheaper than just specifying something that seems right out of a hobby bearing place. What glue is that for gluing aluminum car parts together? Do you have a link to where I could buy some? That could solve a lot of problems.

The controller looks nice, and its probably great for such a portable rig, but I too would suggest Dragonframe or Mantis software for controlling it at some point in the future. You can keyframe moves, which is real convenient if you want to track a foreground object while dollying past it. Here's a demo of Dragonframe to make you drool until you break down and buy.

https://vimeo.com/49291544

I'm biased though, we sell the interface box for connecting your computer running Dragonframe to motor drivers. We also sell stepper motor drivers as well. Here's a link to our online store.

http://www.stepoutmoco.com/

Click on the "shop" tab to see whats in the store.


Fri Sep 05, 2014 1:46 pm
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Post Re: Homemade Dolly/Jib
Yeah nearly everything came from McMaster including the bearing, their 3d cad files make design very very simple.

The glue I used is Fusor 112/113B, it should be available at most auto paint jobbers (places that supply body shops with paint and supplies). I run a jobber store so I get to play with all this stuff. If they don't have the Fusor brand look for 3M, SEM, Dominion Sure Seal, or whatever else your local shop carries. Trade name is just Panel Bonding Adhesive. Just be sure to ask what prep is needed for aluminum.

I'll have to take a look at that software, looks interesting.

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Fri Sep 05, 2014 3:04 pm
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Joined: Tue Apr 09, 2013 6:49 pm
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Post Re: Homemade Dolly/Jib
Hey Dan,
nice jib. How are you finding the swing axis in regards to settle time? Have you gotten that far in your testing? The reason I ask is because once you get a camera package at the end of that jib and counter weights at the other you will have quite a bit of weight to deal with. Once you get finished, shoot a video of the thing during testing so I can add it to my vimeo channel.

Cheers,
Doug.


Sun Sep 07, 2014 8:01 am
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Post Re: Homemade Dolly/Jib
Settle time isn't bad, at its slowest speed its doing 1 microstep every 4 seconds. There is a tiny bit of jitter but its easily corrected so far. More worried about wind.

Trick is to make sure that you don't perfectly balance it, you always wanted it a bit heavier on the side that is going up (so if the camera is going up than make the camera side a little heavier) to eliminate backlash. You don't want it too heavy though because the last thing you want is the camera dropping right at the ground before of power failure. Just a slight imbalance.

I drove out 30 miles into the mountains to do a nice sunset test and... I forgot my counterweights at home. Tried to improvise with rocks but it was not ideal. Instead just did a quick sunset timelapse to test out some magic lantern stuff. I'll have to go out again this week.

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Sun Sep 07, 2014 10:19 pm
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Post Re: Homemade Dolly/Jib
Interesting. Thanks for the tip;) You should check out the crane I made. Here is a clip on my Youtube channel.
http://youtu.be/kJe27KqhdTc?list=UUfbDl ... DtQE7jaMFg

Cheers,
Doug.


Tue Sep 09, 2014 3:44 pm
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Post Re: Homemade Dolly/Jib
Very nice!

Its been well over 100F here lately and the hills near my house where I usually test my gear are currently on fire so I opted instead to stay inside this weekend and work on the code a bit. I got the LCD working nicely, displays the time in minutes since the timelapses started and how long it will take each axis to complete its range of motion.

Image

Did some testing in the garage and everything is working nicely so far. Power consumption is a problem though, I will likely be switching to geared stepper motors to get away with using far less current to move things around.

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Sun Sep 14, 2014 2:51 pm
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Post Re: Homemade Dolly/Jib
danwatt wrote:

Did some testing in the garage and everything is working nicely so far. Power consumption is a problem though, I will likely be switching to geared stepper motors to get away with using far less current to move things around.

That will make no difference . You need to put steppers into low power mode between moves or buy a better battery , Downside of steppers they pull power and the more you have the bigger the problem .
D1


Mon Sep 15, 2014 12:47 am
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Post Re: Homemade Dolly/Jib
I believe I can use reduced current (adjustable on the drivers I am using) with gear motors as I won't need to run them at full torque like I do the current steppers as the gear reduction will take car of that. With the gearbox I won't need nearly as much holding torque so I can cut power to the motor in between steps.

I do have several deep cycle batteries mounted in my truck for powering my astrophotography rig so if all else fails I can always use that. Of course I'll be limited to how far I feel like carrying a huge deep cycle battery through the desert (or how close I can get my truck to the action).

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Mon Sep 15, 2014 8:17 am
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Post Re: Homemade Dolly/Jib
Think Mike A as had a lot of success with these batteries. http://www.deben.com/tracer-battery-pac ... -pack.html. Not cheap but solves a lot of problems . Mike as quite a big rig all steppers and i don't think hes had any power issues .

D1


Mon Sep 15, 2014 9:32 am
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Post Re: Homemade Dolly/Jib
If the motor gearing can effectively hold the rig in position without power then you can sleep the drivers inbetween moves. This will reduce power consumption very significantly..


Mon Sep 15, 2014 9:47 am
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Post Re: Homemade Dolly/Jib
A word of warning on the gearbox front specially on the boom and swing . The play in the gearbox will be a issue you have already mentioned preloading the boom with a heavier balance to one side . You may have to find a similar solution on the swing . A small degree of play is greatly exaggerated by the length of the boom .
I avoided any gearboxes with play in my rig for that very reason .
D1


Mon Sep 15, 2014 10:47 am
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Post Re: Homemade Dolly/Jib
If I can just chime in my 2c worth.....
You will definitely want to sleep the steppers between moves to save power, but, you cant be using microsteps if you are going to sleep the stepper because as soon as it sleeps it will 'notch' over the closest full step.
So, ensure that you are using full steps only.

Also, you said that you were using gearboxes, but you need to have worm drives so that the boom can drive the stepper. A planetary gearbox can be driven by the load, but a worm gearbox cannot.

Great project, looking forward to seeing some results.


Mon Sep 15, 2014 11:49 am
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Joined: Wed Jan 20, 2010 4:50 pm
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Post Re: Homemade Dolly/Jib
Dan

Nice example of a simple boom rig for stopmo and animation. Gearing down the swing and lift would be a good idea. Planetary gears on the motors or a worm drive, even a second stage of belt or a straight cut gear - any will work. It depends on what you can find at the right price... I prefer not to use worm gears myself since it's a real pain to manually reset the boom when motors are off. Much easier if you can backdrive the arm.

With gears you can probably even down size motors to nema 17. Though the current saving may not be huge. If you use drives like leadshine (cheapest model ~ $50) they have automatic half power standby mode. But more importantly - they are more efficient than simpler drives, so less wasted heat and less power needed, in addition to the standby saving. BTW - Contrary to Adavis's advice, you can use them in microstep mode without significant movement from the rest position. And with more gearing any slight adjustment will be reduced anyway. Full step mode is not pretty... :)

Backlash? Well if you are only moving in one direction during the shot it's not worth stressing too much about. Just make sure axes are preloaded in the direction of travel, and in the case of boom lift, balance the head slightly heavy. Or else use a bungee cord or a coiled clock spring.. :)


Tue Sep 16, 2014 7:55 pm
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