EDIT: for an updated look at the Motus project including the new pan/tilt head, please visit http://www.motusmotion.com
For the last 2-3 months, I’ve been working at a fervent – border line obsessive – pace trying to get Motus to a functional status. Motus is a DIY time-lapse and video motion control linear slider system built on the open source architecture of Arduino as well as my previously self-built slider. The original motivation behind powering the motion of this slider was to create smooth, highly repeatable motion for use in video. Not only does this offer a highly cinematic feel, but it also allows you to begin considering special effects such as composting several takes together.
I chose to use a stepper motor as the workhorse for the slider. The advantage of these motors is that you don’t need an encoder to know at which position you are; this means that I could set position and repeat it very precisely. Given this fact, I expanded the features of the slider to time-lapse as well — after all the hardware has been put together, time-lapse is then simply software driven.
Everything is controlled through the compact control box which includes a small but highly readable OLED, a PlayStation type joystick, as well as various buttons for user input and ON/OFF control. As far as I/O goes, we have a port for AC power (12V, 5A), a 5-pin DIN (240 degree) for the stepper, a 1/8″ stereo jack used to trigger the camera, USB-B port into the Arduino to load new sketches, as well as another 5-pin DIN (180 degree) hooked up to two analog pins on the Arduino for expanded use (light meter anyone?).
Some features and specs include:
- Nema 23 stepper motor with 173 oz-in holding torque
- Position precision of 0.17 mm
- Precise motion control for smooth video operation
- Manual video move (direction/speed) or movement between waypoints
- AC (wall-wart) or DC (battery) powered
- Open source architecture
- OLED display for high contrast legibility, even in direct sun
- 4ft long slider, max motion is 1-2 inches less
- Acceleration for damped starts
- High torque for incline/decline moves
- HDR timelapse shooting
- Time lapse setup options:
- Manual or automatic choice of interval
- Immediate or specific time based start
- Motion between waypoints or overall length
For those interested, I offer the following parts list grosso modo; it isn’t complete for several reasons, a few of them being: (A) each project is specific to your needs and will be constructed differently, so there is no sense in going into the small details which globally don’t change anything; (B) I believe open-source and open-ness doesn’t mean I should show every little detail and write up an entire walk-through. Rather, I believe it should motivate to learn and inspire to dream; to that end, if I showed you all the details, you wouldn’t learn as much — and gain an appreciation for it all — as if you, instead, went out to the interweb and searched for solutions to your specific problem. So, with that being said, here are some of the parts I used.
- Pushbutton 1 & Pushbutton 2
- Rocker switch
- DIN Female & Din Male
- Stepper driver
- Timing Pulleys
- Timing belt
- Pillow block
I haven’t created much footage with the slider yet, however I can already share two pieces. The first was shot entirely with the slider, using the motion control to get smooth moves; the second was a quick sunset time-lapse test I did recently. Enjoy!