Motion Mate

MoCo Rig

The Motion Mate system is the core part of my bachelor’s thesis. I constructed and built it from scratch and designed it towards the highest capability and flexibility. The whole system can easily be adapted to any other stepper driven device.

The target was, to come up with a system, being able to handle common DSLR Cameras, as well as ones the size of Blackmagic’s Cinema Camera. It should have the following features: Linear movement, pan, tilt and roll axes, as well as a focus motor. Besides that, the power consumption should be low enough to be able to power everything by battery for field usage.

I started designing in CAD and because I had the opportunity to use a waterjet for cutting out parts, the whole construction was based on 6mm aluminum. To meet the high forces and keep the power demand low, standard NEMA 17 Motors in combination with worm drive gears were used for the remote head. This has another huge advantage because if you cut off the power supply the system will keep it’s exact position, so that you only have to initialize it one time on set.

CAD Model

The systems base was made out of 40X40mm slot profile, making it easy to adapt for different shooting situations. It also allows the attachment of lamps, what makes it a single and compact unit, reducing the risk of accidentially displacing anything by stepping back from the scene.

Base frame

For focus automation, I decided to use a small stepper motor with a planetary gearbox attached to it. This combination is powerful enough to securely drive the focus rings of different lenses, and by adjusting the motors power, it can be tuned to stall if it reaches the lenses focus limits to prevent any damage. A 3D printed mounting bracket as well as a plastic gear + self made shaft-adapter make the focus motor ready for use.

Focus motor

Since precise and powerful linear actuators aren’t the cheapest thing to buy, I was very lucky my lecturer found this project interesting enough to offer me a used unit, I just had to adapt to my needs. This unit has a ball-drive mounted to a powerful NEMA 23 stepper in direct drive and highly precise linear guides, making it the best thing to have for this application.

Linear actuator

This is what the actuator looked like, as it was handed out to me.

After all, a huge amount of manual work had to be put into this project. Every single hole had to be machined at least 3 Times and all the screw threads were put in by hand. Many budget focused detail solutions had to be found and since most industrial-mechanical parts aren’t available for private customers I had to spend a lot of time on searching for suitable substitutions.

The current interface is based on an Arduino Mega 2560 and runs with the commercial stop motion software Dragonframe. In the future, I want to add some custom firmware and standalone control options.

The complete rig

Here you can see the whole rig, as it was used to create the video you can find here.