Introduction: 3D Printed Time Lapse Dolly

Picture of 3D Printed Time Lapse Dolly
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A time lapse dolly adds a very dynamic touch to a normally static form of photography. I have built several dollies over the last few years, my first used a BBQ rotisserie motor and what ever else I could find in my garage. The results were pretty good for being made out of garbage. I have built and learned and I think my latest system is the best yet. Using 123D and 3D printing I was able to create and print several custom parts to produce this dolly. I am trying to raise enough money HERE to sell these systems but I am more than happy to share my build plans and 3D files with everyone. I know not everyone has a 3D printer but there are many printing services online that you could use. I am planning on selling kits ranging from just the plastic parts printed or injection molded, if I can raise enough money, all the way to a complete system as well as combination in between including the electronics and motor.

This new dolly is lighter, stronger, cheaper, faster to set up, more compact, and better looking than my last one.

Here is a promo video I made.


Lets get on with the build!

Step 1: Parts Needed

Picture of Parts Needed

Lets start with the 3D printed parts. You can download them HERE or from the 123D gallery but I haven't figured out how to link to the files, I will update this. If you want to  you can buy the Plastic Kit HERE

Here is a link to the printable pieces of the V2 kill switches.

You will need:

4x Slidetracked Slider Bracket

2x Slidetracked Belt Grip top

2x Slidetracked Belt Grip bottom

2x Slidetracked Microswitch Mount

Optional 3D parts.

2x Slidetracked Idler

1x Slidetracked Cable Clip x 6

Store bought parts:

14t Pulley that fits the belt and motor you use.

6.5' timing belt, I'm using a 5mmHTD 9mm or 3/8 XL

1x 3"x 1.5" x .188" aluminum channel 6'

3x 1.5" x 3/8" x 2.5"  flat bar

1x 9" x 9.5" x 3/16" aluminum sheet

1x 1-2 rpm motor I used this one

1x PWM I used this one

1x enclosure for the PWM

4x switched DC power jacks

4x DC barrel plugs

1x Normally open momentary switch

2x Long arm lever micro switches

1x 3/8"x 3/4" x 6" UHMW

1/4 20 screws 3/4, 1/2, 1 1/2, nuts, nylocks.

Step 2: The Dolly

Picture of The Dolly

We need to layout the plate to mark all the holes.  The first thing you want to do is find the center and distribute the the four Slidetracked Slider Brackets from there. The most important part is to make sure your brackets are straight  there is room to move the brackets tighter and looser to the rail.

Mark the holes for the two Idlers, the placement of these will determine where you mount the Belt Grips on the rail, make sure you leave enough room from the edges of the rail so that the dolly will clear the Belt Grip bottom, be sure to read the rail step before drilling these holes.

Next mark out where you want your motor to go. I chose near the edge next to a Slider Bracket, This keeps the motor out of the way.

Pick where you want to put your camera, don't get too close to the edge.

You will need to mark out and drill the holes for the Microswitch Mounts but wait until the rail is built so that you can line them up with the Belt Grips, this is what they bump into.

Now center punch your markings so that the drill bit won't dance around and the holes go where you want them.

I used 5 different drill bits and a step bit. The holes for the Slider Brackets need a 1/4" hole. The holes for the idlers are threaded 1/4 20 so the drill the holes with a  13/64 bit. The hole for the ball head is 13/32, the hole for the motor shaft is 1/2, and the holes for the Microswitch Mount and to mount the motor is 1/8. After the holes are drilled use a larger drill bit to chamfer the holes a little, just to clean it up a bit and remove burrs.

Cut four 1" lengths of UHMW and push them into the four Slidetracked Slider Brackets. Place the 3/4 1/4 20 screws in the brackets holes and mounts the brackets, put the nuts on but don't tighten them up yet. once all four brackets are on put the dolly on the track and squeeze the brackets snug to the rail, don't make it too tight but make sure there isn't room for the dolly to twist.

Step 3: The Rail

Picture of The Rail

This is the single most expensive piece of the whole system, it is also the most important. You need to use something straight and strong, for this I used something that I think you can get in any decent sized city and easy to find online. I used 3" x 1.5" x .188" aluminum channel.

There are 10 holes to drill in the rail 4 for the timing belt holders and 6 for the tripod risers.

Lets start with the risers.

The risers are needed so that the dolly does not hit the tripod head below. I used 1.5" x .5" flat bar aluminum 2.5" long. I marked the center for the tripod hold and the other two holes for mounting to the rail. Drill and tap the holes with * bit and 1/4 20 tap

Find the center of the bottom of the rail. I offset the riser 2.5" from the edge of the rail. mark the outer two holes from the riser and drill with a 1/4" bit. do the same on the other side and the center of the rail to give you 3 tripod points.

The placement of these is very important. you have to line them up with the idlers underneath the dolly so that the belt is straight. once you figure out the location simply mark the holes and drill them with a * drill bit and cut the threads with a 1/4 20 tap.

Screw all the pieces on and your rail is done.

Step 4: The Electronics

Picture of The Electronics

*This part of the dolly is still in development, I will continue to update as things change*

Now it's time to wire your PWM. The basic use of the PWM is very simple connect battery to PWM, connect PWM to motor, easy. We want to complicate things a little. The kill switches are a safety feature, they will stop the unattended dolly at the end of it's run. It is fairly simple to wire up but I find it hard to explain, here we go.

The idea here is to have the micro switch interrupt the positive to the motor. this is done running the positive through  the normally close connection on the switches, when the switch is triggered the power gets cut. I've added a bypass so that you can back the dolly away from the trigger point. this is just a normally open switch that is on a line the goes from the battery to the motor, when pressed the power will by-pass the micro switches.

Laying out the enclosure takes a little time to make everything fit, take your time. Attach the enclosure to the dolly with some two sided foam tape, or you can drill holes if you want.

Step 5: The End

Picture of The End

That's all for this build! Thanks for taking a look!


ilpug (author)2012-04-08

Nice build! I must ask though, how did you do your profile picture?

DerekMellott (author)ilpug2012-04-10

I have been using this pic for a few years. Just yesterday posted a how to.

DanKoz (author)2012-03-21

Is my understanding correct that you are selling a complete kit for $300 US? If so, does that include everything, including the motors? If not, what else would I need?

I am not mechanically inclined so building a unit from scratch is probably not feasible.


DerekMellott (author)DanKoz2012-03-21

The $300 kit does not include the rail, this option is aimed at people outside of North America in order to avoid huge shipping costs. This kit has everything else. None of the kits include the ball head, tripods, or intervalometer.

The $400 kit includes the rail.

If you are overseas I can give you the info you need to find a rail locally. A template will be sent to assist in drilling the holes in the rail.

Check out for more info.

motleypixel (author)2012-03-14

Houston, we may have a problem :( Just received my AL channel...Derek, is this going to work?

I didn't realize it tapered so thick towards the cross-member. the only dimension I left off is the width which is close to 3 inches. Man, this is a final sell cut too :(

DerekMellott (author)motleypixel2012-03-14

You should be ok. there is a chance that top hook of the piece may rub, if is too tight you can use a hack saw to trim it. What is the width of the rail 1/2" down the taper? the gap is 7mm that is just over 1/4 inch.

motleypixel (author)DerekMellott2012-03-16

Derek, you think I'm okay with my chl stock?

motleypixel (author)DerekMellott2012-03-15

Oh, also, what about my legs, they are 1 3/8th" long, not 1.5", is this okay? Esp. when the rail is at angle?

motleypixel (author)DerekMellott2012-03-14

1/2" down from the top of the taper is .292" thick. Is this okay? When you say hack saw and trim, you mean the printed foot, not the rail right?

motleypixel (author)2012-03-14

It would be super cool if you could make a printable template or just sketch out the 9X9.5" plate and then measure out from 2 edges each hole on center :) Would make the process some much faster for those building per your design :)

DerekMellott (author)motleypixel2012-03-14

I should have the time to do that before the parts ship.

motleypixel (author)DerekMellott2012-03-14

sweet...I've got time...that motor will take at least 3 weeks to get here...need to take my time anyway...don't want to rush this build. thanks for considering.

motleypixel (author)2012-03-05

...darnit, forgot one more thing. Curious about the PWD and behavior of the 2rpm motor with a 12VDC source. With 12VDC and 100% modulation (pot cranked all the way up the motor should maintain a stead/smooth 2rpm right? Then with the pot at 50% it's 1rpm right? Just out of curiosity will it smoothly rung at .5 rpm at 25% modulation?

DerekMellott (author)motleypixel2012-03-05

The PWM runs smooth at all speeds, I am working on adding, shoot, move, shoot functionality.

I will add additional files for that profile when I can get my hands on a chunk of it, hopefully this week.

Here is a link that shows me the profile, I dont know what it will show you because it won't let me search outside of Canada.

motleypixel (author)DerekMellott2012-03-14

Well I have the channel, all AL stock, that ebay 2rpm motor on the way from China, t-belt, so all that’s left is to assemble my PWM board (yes it came, ready to assemble) and start the construction process once I receive the plastic parts. I’m still wondering about the speed of the dolly/truck? I will be using the system to capture milky way time lapse sequences which often have settings of f/2.8, ISO 2000, and 30 second shutter with 3-4 second delay between shots. I can’t have the dolly moving too fast or it will blur foreground subjects. If the motor is a 2rpm motor at 12vdc, then I wonder how slow I can make it with an 11.1vdc lipo battery and my pwm cranked back say at 25% modulation (would this be roughly .5 rpm)? Larger t-belt pulley will make it go faster and smaller will make it go slower right? I know you are providing 1 or 2 printed pulleys, are they the same sizes? Just trying to get a pulse on projecting speed and if it’s going to be in my target range, of which I have no idea of the actual speed of the truck, it just has to work with the footage.

DerekMellott (author)motleypixel2012-03-14

I was going to put two of the same sized pulleys in the kit, a bigger one would add speed there isn't much space down there so it wouldn't be much. I've only had a chance to test it at night twice. The pwm I use allows 10-100% of motor speed however the dolly doesn't start to move until about 15% this moves the dolly about 9/16" a minute. From my testing this feels to slow, the pictures were crisp, I need to test faster speeds perhaps 25% is good. You will need to experiment to find what works for you. I am working on a module that you can add in line to the motor that will stop the motor for your pictures, but that is still in development.

motleypixel (author)DerekMellott2012-03-14

Okay so if the rail is 6’ (probably a little less because of the t-belt clamps etc.) so let’s say 5.5’ which is 66” and at the “too slow” speed of 9/16th” per minute we are looking at roughly 117 minutes to travel the length of the rail…that’s under 2 hours which is around my minimum time for night time-lapse. See if I’m taking one shot every 34 seconds (30 second exposure and 4 second delay), that’s only 207 frames which at 30fps is only 6.9 seconds of footage. My pwm modulates from 0% to 100% so I’m hoping at less than 12vdc (11vdc, lipo battery pack) and 25% modulation I can get a little slower travel.

DerekMellott (author)motleypixel2012-03-14

That all sounds about right. If you watch some of the professional timelapses their clips are not very long, a six second clip is about right. The shoot-move-shoot would extend the movement to many hours.

motleypixel (author)DerekMellott2012-03-05

I found it, thanks:

(3" x 1.5" x 0.188" ALUMINUM 6061 T6 CHANNEL)
Sku: AC6061/3112316

Too bad they don't show a price...I have to call them to get a quote. I called our local supplier, what do you think of these dimensions, will this one work?

3" X 1.41" X 0..170" ? < This is $41 plus tax locally.

I talked to them about the .125" stuff and I know why it's cheaper, it's not structural and from what I told him he said that the .170" + sizes will be better and more sturdy, so maybe you shouldn't get that .125" channel to test? It sure seemed sturdy enough to me.

I'm waiting for a quote on the .188" from metalsupermarket, may I'll just use that since it's what you designed this system around.

DerekMellott (author)motleypixel2012-03-05

The 3" x 1.41 x .170 should work just fine, smaller will work, bigger would be an issue.

rocco (author)2012-03-05

Great project! Finally a motorized slider that I might be able to afford!!!
I do have a couple of questions:

I'd love links to more of the store bought parts, like the pulley, timing belt, and UHMW that you used? I suspect that sells them all, but was wondering if you found a better/cheaper source?

Could you show how the pully contacts the timing belt? Other designs seem to have the pulley wind around some spinning guides (idler roller bushings) to ensure that the pulley keeps good contact with the belt - did you do this? I'd love to see a picture of that part of your design!

Thanks for sharing!

DerekMellott (author)rocco2012-03-05

I printed the pulley and would include one, or two with the plastic kit.

If you wanted an aluminum pulley get this one.

This is the right belt at a good price.

I'm in Canada and I bought the UHMW at . There must be a better option in the US.

I think the final plastic pieces I will be selling will be made from Nylatron and the UHMW will not be needed.

I am using a 3500mah 12v battery, I have never drained it but I charge it after every time I use it, I usually have a few with me plus other back up battery sources.

Yes, the belts runs around two idlers, I will add a pic to the dolly step.

motleypixel (author)DerekMellott2012-03-06

"I think the final plastic pieces I will be selling will be made from Nylatron and the UHMW will not be needed."

Do you have any time-line for these newer plastic pieces and will they be the same cost?

I've ordered the 3" x 1.41 x .170 (6') channel...looks like I started the ball rolling :)


DerekMellott (author)motleypixel2012-03-06

The Nylatron parts will ship the same time as everything else, the price during the indiegogo campaign will not change.

motleypixel (author)DerekMellott2012-03-06

Are parts shipped now or only after the indiegogo campaign on Apr. 30th? And will the Nylatron be used instead of plastic regardless if goal is met? They are still 3D printed right? Not injection molded, correct?

DerekMellott (author)motleypixel2012-03-06

Well that depends, if the Nylatron works and is economically feasible I would have to order many of them at a time and then yes, regardless of reaching the goal or not this method will be used. The money is held by indiegogo until the deadline. It may be possible to ship early, printed parts could ship tomorrow.

motleypixel (author)DerekMellott2012-03-09

Ordered the plastics parts only kit...looking forward to the Nylatron version :)

rocco (author)DerekMellott2012-03-05

Awesome! Thanks for the speedy info and links! :)
I'll have to look in to Nylatron vs. UHMW - I don't know a darn thing about plastic! :)

motleypixel (author)DerekMellott2012-03-06

I'll wait until you iron-out details on the Nylatron version before I do a purchase of the plastic kit as I would much prefer the Nylatron over the plastic. Also, just FYI, I called the metal supplier you referenced for a quote on the .188" and a chap from Canada called me back. He said he couldn't quote me a price since I was US, but he had suppliers in the Dallas, TX area (I'm about 3.5 hours from Dallas). Just wanted to mention it as it's seeming possible reciprocal issues for US people to your issues in Canada. Like I said, I ordered the 3" x 1.41" x .170" channel as that's very close to the dimensions you used. Might I suggest maybe a tolerance in dimensions to the channel that could be used with the feet you have engineered? This way future people engaging on this project can have a little leeway with channel sizes.

DerekMellott (author)motleypixel2012-03-06

The leeway already exsists, it will tolerate smaller dimensions but not bigger. I would have only sent you the plastic if you requested it. You can buy at anytime, I will ship when the parts are finalized and produced.

rocco (author)2012-03-05

I forgot to ask about the battery you're using! What are the battery specs you use, and how long does it last before needing to be recharged?

Thanks again!

motleypixel (author)2012-03-05

Thanks for adding more detail. I know I can buy 1" X 3" X .125" AL channel locally, decent price at $20 for 6' but wanted to check out as you suggest and oddly enough I can't seem to find the channel you are using. I tried selecting all grades of their AL channel and I can't find the right dimensions. Also, it seems they are flipping the top width and edge height dimensions...closest I could find is 3" X 1" X .125" There were only a few .188" but not of 3 X 1 or 1 X 3. If I missed it, then can you provide the grade and dimensions (as they have it on their site)?

BTW, I checked out the .125" AL channel at our local shop...definitely rigid enough at 6'...just the extruding of the channel make is super rigid. I mention this because it's seeming that there's better stock around of the .125 or 1/8" channel vs. the .188 and it would be slick if you were able to chirp the dimensions of the 3D printed plastic feet and provide a .188 and .125" option?


motleypixel (author)2012-02-29

Thanks again Derek, more questions :)

What does this piece do? and this piece? and finally these pieces?

I have access to 1"X3"X.125" (1/8") AL channel, I can't find any .188" thick channel, will 1/8" channel work? I'm thinking the slide feet would need to be a little tighter by .063" to work right? Can you share which motor you are using? Another great build-help would be to provide a template of sorts for the holes to drill in the dolly truck (sorry if you have and I've missed it). Overall how do you think this version slides (smoothness etc.) compared to your previous bearing version? In fact, over-all could you provide a short list of the imporvements as you see them?

DerekMellott (author)motleypixel2012-02-29

Thank you for your question, you have pointed out a few things I have missed and I will update tonight to clarify what all the parts are for and what motor and PWM I used.

The first part you asked about is the mount for the micro switch. You can see it in the video where the dolly is turning off at the end of the run.

The second part is just a dust cap that goes on top of the motor to keep dirt or sand out of the openings on the top of the motor.

The last part is clips I used to hold the cables in place underneath the dolly that run from the micro switches to the PWM.

I've uploaded the original files to the 123d site but I can't find a public link to them. With these files you could adjust the parts to suit your needs quite easily in the free 123d software. The profile you have will work, you just need to adjust the build to suit your needs. Be aware that changing the depth of the rail will effect the the height of the timing belt, alterations will be needed.

This dolly is much easier to build as long as you have the parts. Is is much lighter, has a smaller foot print, takes about 10% of the time to set up, and the rail is much stronger, no need for the hard case to protect it.

This one slides as smooth as the rail is. If there are an nicks or bumps on the edge of the rail use a file to knock them down. I'm now trying to adapt this to used for video, the other one was too loud and had a lot of vibration at speed, we will see how this one performs.

motleypixel (author)2012-02-28

Derek, Looks like you've made a beautiful, functional, very clean rail/dolly time-lapse system here. The first question that pops into my head after reading through all the steps and seeing some of the prices of the plastic parts is what sort of budget are we looking at here?

If I had the money to spend, which I don't, to buy this system: then I would, so this is why I'm looking to machining/cutting/buying/spending time and building a full DIY version for a fraction of the cost.

Are the 3" Al channel plastic guide feet all your engineering or are they available on the open market?


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