Light Painting Machine

   Sometime in December, I had this idea to make a machine that could accurately and repeatably  draw light paintings, so I could use it to make light painting animations in a way I thought hadn't been done before.

Working on a universal stepper joint for #motioncontrol that plays nicely with 15mm rail systems. The idea is to attempt to make something compact, rigid, and versatile. You should be able to grab three copies of this and some rail blocks and put together a pan/tilt/roll head. I'll start making these parts in about a month, we'll see then how well it does.

A post shared by Josh Sheldon (@heyjshel) on Dec 23, 2017 at 1:14am PST

New rear plate for old box.

A post shared by Josh Sheldon (@heyjshel) on Jan 22, 2018 at 2:43pm PST

Could be better maybe.

A post shared by Josh Sheldon (@heyjshel) on Jan 26, 2018 at 5:43pm PST

I think I'm pretty much done with the painting control box. Had to redo some stuff after burning out an Arduino, but attempt 2 is a little neater anyway. It all ended up being much tighter of a fit than I was expecting. I had to remove stepper drivers from their housings and cut down the powerful supply, and I couldn't run wires as neatly as I'd like. Overall pretty good though. It looks nice with the cover on, and it's got a nice weight to it.

A post shared by Josh Sheldon (@heyjshel) on Feb 1, 2018 at 6:17pm PST

LED + tube mount. Kinda winged the design but I'm really happy with it. I just have to figure out how to put a box around this so there won't be light leak from anywhere but the end of the tube. Probably gaff tape.

A post shared by Josh Sheldon (@heyjshel) on Feb 2, 2018 at 4:50pm PST

Horizontal axes. I've never worked with 80/20 before, what a joy! Some placeholder hardware here for now until I get some packages.

A post shared by Josh Sheldon (@heyjshel) on Feb 3, 2018 at 7:53pm PST

After lots of fighting, I finally got the drivers working, a bunch of software issues worked out, and everybody properly talking to each other. Initial image tests should be pretty soon!

A post shared by Josh Sheldon (@heyjshel) on Feb 10, 2018 at 1:28pm PST

LIGHT PAINTING MACHINE FIRST TESTS BIG SUCCESS!!! It's going way better than I could have hoped for. Just need to work out some wobbly issues with the rod by making it stiffer and/or fixing some little motor stutters.

A post shared by Josh Sheldon (@heyjshel) on Feb 11, 2018 at 8:15pm PST

New linear moco axis. This is what the plate from the last post was for.

A post shared by Josh Sheldon (@heyjshel) on Feb 20, 2018 at 10:33am PST

A post shared by Josh Sheldon (@heyjshel) on Feb 28, 2018 at 4:21pm PST

Configuration of three stepper units into a pan/tilt/roll head. Just one possibility, if these little joints come out nice and sturdy, they can be used for anything! #motioncontrol

A post shared by Josh Sheldon (@heyjshel) on Dec 24, 2017 at 7:58pm PST

Making a housing for stepper drivers. Started with a 2u server chassis, removed a fan and cut out part of the front panel to replace it with this aluminum switch plate, which seats nicely behind the original front panel. I'm taking inspiration from @biolapse to use a server chassis and have disable switches for each driver.

A post shared by Josh Sheldon (@heyjshel) on Jan 23, 2018 at 10:23am PST

box is coming together!

A post shared by Josh Sheldon (@heyjshel) on Jan 26, 2018 at 11:15pm PST

Fresh new rear plate for driver housing! RJ45 inputs from dmc16, 4 pin aviation connectors out to steppers. 8 channels for this box, if I eventually want to use all 16 outputs from dmc16, I'll make another copy of the box. I wish I had the foresight to extend the plate up on the right side to cover those ugly gaps from the rear panel bays. I might figure something out for that later.

A post shared by Josh Sheldon (@heyjshel) on Feb 1, 2018 at 10:57pm PST

Vertical axis

A post shared by Josh Sheldon (@heyjshel) on Feb 3, 2018 at 9:16am PST

Needed more length, so this acrylic rod replaces the old glass rod. The acrylic is pretty flexible and not nearly as rigid as the glass, so I built out this support piece to help keep it in from oscillating too much while moving.

A post shared by Josh Sheldon (@heyjshel) on Feb 8, 2018 at 9:02pm PST

Moco stepper driver box is done! #motioncontrol

A post shared by Josh Sheldon (@heyjshel) on Feb 11, 2018 at 2:49pm PST

Party pack post: 1. strain relief for LED. 2. little ball of hot glue perched at the end of the acrylic tube. This is to diffuse light evenly in all directions so it can be photographed from any angle. 3. New 1/4" plate for a moco axis later. 4. Spade bits in aluminum works pretty nice.

A post shared by Josh Sheldon (@heyjshel) on Feb 12, 2018 at 12:25pm PST

Tiny college apartment shooting setup. Mattress is lifted up and everything is set up on the bed frame, which the machine is strapped to with ratchets. Blankets on the walls to block window light and reduce direct and ambient light reflections. ~ ~ ~ Also little update on the machine: the z axis is now upside down so it shoots underneath of itself, there are proper cable carriers now, and it's got a little plywood shooting table. ~ ~ ~ Also, quick tip: you can tie a bunch of your rack gear together just by buying some little rack rail sections for cheap. Much less space that getting a full rack. #motioncontrol #stopmotion #dragonframe

A post shared by Josh Sheldon (@heyjshel) on Feb 28, 2018 at 12:39pm PST

Got a bash light set up, so much better than working in the dark. This is showing a quick little calibration shot to help get the cube in the right position on the stage.

A post shared by Josh Sheldon (@heyjshel) on Mar 1, 2018 at 10:36am PST

First light painting animation test! Also blender render and scene. I learned and improved a ton while shooting this and there's still a lot to improve. Lots of issues with the light knocking the cube. Obstacle avoidance is a little refined now. There's also some draw failures here, mostly when the machine can't execute the entire painting in under 30s, which is my max exposure time. I think I can improve this a little with better draw order optimization. I don't think I can just increase the speed of the machine movement without causing a lot more oscillation, which is already a big problem. The machine isn't really rigid enough to draw smooth paths quickly. Also having some problems getting a consistent home position with the limit switches, I think particularly on the Z axis. This is why every few frames the entire animation sometimes jumps vertically a little bit. I made some improvements to the homing process in software, but doesn't seem totally fixed yet. Still thinking about this problem.

A post shared by Josh Sheldon (@heyjshel) on Mar 2, 2018 at 1:27pm PST

Take 3, this one a composite of two exposures per frame. Same draw speed as last time, 10cm/sec. F2.8 ISO 160, 20 second exposures, shifted it up to 25 seconds halfway through. 35mm lens on APS-C sensor. This time shooting raw instead of jpg. For some reason any format except for full size raw was giving me some strange starry noise, as if there was a ton of hot/stuck pixels, but they weren't single pixels, more like blobs 4-5 pixels across. Anyone know about that? * Looks like I'm still having the homing issues. After digging through 3D printing and CNC forums, I'm somewhat confident my problem is with cross-talk from my unshielded motor cables to the limit switch cables. From what I've gathered, there are three solutions. In ranked order of my confidence in their effectiveness, I could: 1. Separate the motor cables from the limit switches, take one set of cables or the other out of the cable carriers. 2: Replace motor cable with shielded cable. 3. Add 0.1 uf capacitors between ground and each switch. I'm going to start by trying approach 3 because it's easiest to implement. We'll see what happens and go from there. Stay tuned for take 4.

A post shared by Josh Sheldon (@heyjshel) on Mar 9, 2018 at 9:05pm PST

thinking about swirly things. #lightpainting

A post shared by Josh Sheldon (@heyjshel) on Mar 11, 2018 at 9:09am PDT

A post shared by Josh Sheldon (@heyjshel) on Mar 12, 2018 at 8:51am PDT

Spinny thing v1 assembled! Now just gotta try it out. Hopefully making two more of these over the next few weeks, maybe with some iteration.

A post shared by Josh Sheldon (@heyjshel) on Mar 15, 2018 at 4:25pm PDT

Another late night of shooting, fixing lots of little bugs and working out kinks. A few little fixes with partial paths and prop avoidance stuff. Some path interpretation issues also fixed, which you can see in the first few seconds. ~ This scene is a glass sphere on a little square pedestal. I didn't clean the sphere for this test shoot, so it's got lots of fingerprints all over it. It's kind of neat how the smudges creep around as the sphere rotates because of the vibration of the machine. ~ I really need to find a light-sealable space that is not my bed to set this up at night so I can sleep while it's running. #lightpainting #stopmotion

A post shared by Josh Sheldon (@heyjshel) on Apr 14, 2018 at 9:23am PDT

Was only able to get a short loop out of shooting last night, need to reshoot soon and hopefully get the whole thing.

A post shared by Josh Sheldon (@heyjshel) on Apr 17, 2018 at 12:55pm PDT

Shooting begins! 9:30pm now, with luck I'll be done by like 5am.

A post shared by Josh Sheldon (@heyjshel) on Apr 23, 2018 at 6:29pm PDT

Normally this is done in the dark, but lights are on for demonstration. I'm redoing the same animation to help benchmark my problems. My cable is a little underrated, so the first thing I'm trying is doubling it up for the z axis, which has the longest cable run. Maybe that will help with my consistency problem? I also added functionality to break up frames into multiple exposures, which I can screen together in post. Here I'm doing two 20 second exposures instead of the one 30 second I was doing before, which was barely not long enough. So if the better cable doesn't fix it, I can now afford to slow the movement down a ton, because I can break it up into up to 12 exposures (dragonframe limitation). So now I've got up to 360 seconds (12x30) instead of only 30 seconds to work with for each frame.

A post shared by Josh Sheldon (@heyjshel) on Mar 9, 2018 at 4:38pm PST

Take 4: THE CAPACITOR FIX WORKED!! Alignment issues look gone! Pretty much all systems are working now. * Next thing I want to do is experiment with slower draw speeds now that I have the freedom to do much longer draw times. The wobbly nature of 10cm/sec isn't necessarily bad, just want to see what kind of different path qualities I can get with different speeds. * Mostly for my own future reference, this one is two exposures 10cm/sec, 25s, F5.6, ISO 160, 35mm. #lightpainting

A post shared by Josh Sheldon (@heyjshel) on Mar 10, 2018 at 12:03am PST

num. 3 * * #lightpainting

A post shared by Josh Sheldon (@heyjshel) on Mar 11, 2018 at 4:35pm PDT

Shot for @bengraneygreen #lightpainting

A post shared by Josh Sheldon (@heyjshel) on Mar 12, 2018 at 10:02am PDT

New part for the spinny thing. Hopefully will be able to have it all assembled by the end of the week.

A post shared by Josh Sheldon (@heyjshel) on Mar 13, 2018 at 12:53pm PDT

Three new motor plates. One to replace the last one, and two more for two more units. V2 has the center-center distance a little bit farther and the slots a few millimeters wider, so belt tension will be better and easier.

A post shared by Josh Sheldon (@heyjshel) on Apr 2, 2018 at 12:25pm PDT

Notes for personal reference: - ensure power up time and bash light settling times in dragon frame are all set to 0s to avoid early starts before exposures start. - make sure ~all the bolts~ are tightened before running a long shoot - Need hard end stops for the other side of the x axis, for safety. - ensure DMC16 is set to close relay during exposure #lightpainting #stopmotion

A post shared by Josh Sheldon (@heyjshel) on Apr 17, 2018 at 8:05am PDT

Shooting a scene tomorrow with compound slide + tilt moco axes movement. This will be the first test for the rotational moco axis and also first try doing compound movements.

A post shared by Josh Sheldon (@heyjshel) on Apr 22, 2018 at 10:02pm PDT

Had a great opportunity to exhibit my #lightpainting #stopmotion project at @immersiveatoms this weekend. If you're in the D.C. area, come check it out this weekend! ~ It's hard to fully communicate the project in this kind of format. It's a nice challenge. I'm not sure how well I've done, but at the very least people are really curious. My "Try Me" button pulses, and when it's pushed, it turns off, the overhead lights fade to red to subtly communicate that the lights are off when the machine is going, and the machine executes a little mock demo painting. ~ This show has been my motivation for making animations with this thing for the past month. Really happy with how it all finally came together!

A post shared by Josh Sheldon (@heyjshel) on Apr 26, 2018 at 5:53pm PDT