Friday, September 14, 2012

How To Build a DIY Motion Control Timelapse Rig!

So Reddit seemed to like the footage I put out of the GoPro time lapse rig I made so here is my attempt to lay out how to build one. I dont really have a parts list because a lot of the stuff I got was just walking through Lowes saying "that looks like it will work!" so to make up for it I took lots of pictures.

My starting point was a slightly modified version of Film Riot's video $10 DIY Camera Slider! but with two differences. The end boxes are laid out like the picture to the left so I could attach a cover plate on top. That plate will be used to mount pulleys and the motor to, but I will get to later... I also added a 1/4-20 Brad Hole T-Nut with some JB Weld to the bottom so I could mount tripods/light stands to it later.

The other difference is the sliding part is only made of two "T" joints of PVC, shown on right, so you can mount the GoPro with the standard handlebar mount. These are connected with a small piece of PVC in the middle and glued with a 2 part epoxy. The ends of this part are covered with stick-on felt and an additional bit of electrical tape just to keep it from peeling away. The other bit on there will be used for the belt drive which I will get to in a few.

To build the "Drive Box" I went to a local electrical surplus store and bought a timer motor (110v AC, 3/4 RPM), a larger gear and 2 pulleys. I cant really be too specific here because each motor had a different gear on it and I was fortunate enough to be in a place where I could dig through a box of spare gears to match it up with. I used a drill to make holes in the cover plate for the motor and gear shaft.

On it goes (from top to bottom) a locknut, large washer, a finishing washer, pulley epoxied to gear, and another locknut to hold the bolt onto the faceplate. Tighten the top locknut only enough to keep everything snug but the big washer should spin easily. The finishing washer was to compensate for the larger inside diameter of the pulley. When you slide everything on, the gear should line up with the timer motor.
By drilling slightly bigger holes than needed, you can position the motor so it gears up perfectly, then tighten down with locknuts. To wire it up all you have to do is take an old cord and splice it on, polarity doesn't seem to matter with these things--it spins in the same direction regardless--but check the specs on it to make sure its 110v or 120v AC first. And being AC, it kind of makes varying the speed limited to "on" and "off."
The other side, attach pulley and try to make it as high as the Drive Box side, especially if you wind up making this with a flat belt. What I found works the best however was the black plastic cord that holds screens into their frames, its rubber but not too stretchy and seems to be pretty durable. I found it useful at this point to sand the inside of the pulleys to get a better grip on the belt, and what the heck, sanded the belt too.
Now to make the belt I wrapped the cord around both pulleys and cut it so it was about an inch away from making the complete loop. This will give tension to the belt and prevent slips (that said, this rig can only handle so much weight so any major vertical movements are limited to top to bottom). At the end I attached wire connectors and clamped them down. These will loop onto the metal "U" on the sliding part.
Because the motor will only spin in one direction, the way you attach the belt will allow you to move the other way. By connecting to the inner post (see picture to the right) the camera will move right to left, if you reverse the belt and attach it to the outer post the camera will travel left to right. Attaching to the center post seems to work the best for less slippage when filming at an incline but doesn't seem to affect horizontal moves.
The last step is to make your gear look all official! After testing I chopped my 5-foot conduit down to 4 to make it more portable and found out that it takes almost exactly an hour for the camera to travel this length. Hope you guys enjoyed this tutorial and if anyone has any questions leave a comment below, or for a response this year tweet me. And if you shoot with your own or improve on it I would love to see! Thanks!