Update Summer 2015

I have since built a new, far better, motion control head using an internal belt mechanism, pictured above. Read about it here. This post is left here for those interested in a more simple arrangement.

In May I came across the OpenMoCo project which is a community that is producing an open-source photographic motion control system, concentrating mainly on the software side of the problem. For a while I have been trying out timelapse photography and the idea of creating paning, tilting and sliding shots has been interesting but the equipment to do this can cost more than £1000. Being an engineering student and having access to some machining tools I thought it would be fairly easy to come up with and manufacture a system for myself. Initially I had a look around the OpenMoCo forums and found rigs other people had built, bearing in mind I had only a few days to build the system I decided to base my design heavily off of this pan-tilt head one user built. I had a very limited time and budget so couldn’t risk going with a totally novel design; I knew this had been tested and would work and I also had access to a laser cutting machine so it made sense to heavily take advantage of this prototype.

I quickly modelled a first draft in a 3D cad program, luckily most of the suppliers who I purchased the components from offered cad models so this allowed me to get on with completing the design before I had even received most of the parts. The cad software made it easy to quickly change the design and I had the whole thing finished in two days. The final design comprised of 10 flat acrylic plates which were laser cut using s 50W CNC laser, courtesy of the University of Bath. Four of the plates needed a small amount of additional machining to add threaded holes and to ensure that the ends were properly perpendicular, which is important since the laser cutter leaves a slightly tapered cut.

A render of the cad model for one of the earlier designs is shown above, subsequently the profile of the base sections was changed to create a fully enclosed base. The manufacture was fairly straight forward and was nearly all finished in a few hours, other than the electronics, which is still ongoing. I still plan to add a slider to the system and have the an extra motor and driver board ready for when I can implement this. For the slider I am planning on using either an igus slider or percission rail and DIY carriage. We shall see.

The head is driven by two stepper motors through a worm gear which reduces the motor speed by a ratio of 30:1, this allows 6000 steps per full rotation of the head, and since the motor drivers I use break each step down into 8 microsteps the rig can have a spatial resolution of 48000 points per rotation. The whole system is controlled using an arduino UNO, an electronic prototyping platform which allows a cheap and easy way to program your own microprocessor. Initially I was planning on using the OpenMoCo timelapse engine to control the head but after some time a friend and I decided to come up with something a bit different that would allow manual control as well as programmable time-lapse moves which could continue even without a computer attached to the arduino. The firmware is still a work in progress but in the meantime I will be using OpenMoco.

A picture of the final system is shown on the left, I will update soon with some test footage once I finish the electronics and software side.

Parts list

10x laser cut acrylic plates

18x M4 countersunk bolts

2x M5 Socket head bolts

2x M5 Nylocks

2x 25x42x11mm Thrust bearings

2x 5x12x4mm Thrust bearings

2x A-1Y-5MYK08RA Worm

2x A-1P-6MYK08R030 Worm Gear

Arduino UNO

3x Easy Driver Stepper Driver

3x ROB-09238 – Stepper Motor with Cable

Misc: washers, spring washers, thread insert for tripod mount, tripod screw, diodes, resistors etc…

I will post more information once I have all the software sorted out, at the moment the electronics have just been (semi)finished and I am doing a couple of tests, getting the time-lapse function working with some quick and dirty code but will update when I have something better and more stable. Here is a picture of the messy electronics, the opto-isolators are doing nothing at the moment, they are for later. Enclosure coming soon…

I also hope to use the head for giga-pan photography as well, this is when you take a large grid of pictures at different angles and stitch them together automatically into one much larger image. Also I might try some experimentation with real time macro videography. Any ideas?

Edit: Added first video tests below, just got to iron out the sticking problem at the beginning of the move ramping and things should be working out well.



DIY ARDUINO MOTORISED TIME-LAPSE HEAD from Steven Brace on Vimeo.