WELCOME TO MY DIY MOTORIZED CAMERA SLIDER PROJECT
LAST UPDATED: 16/JANUARY/2016
Given my increasing interest in photography I decided it would be nice to have a camera slider for creating panning shots and timelapse videos. The prices for an off the shelf slider aren't too steep, but for a motorised version the prices range from 'quite expensive' up to 'bonkers', so given my DIY skills I decided it would be more cost effective to build my own with the features I want, so I did.
I had originally planned to go with one of the less expensive ( though not cheap... ) manual camera slider rails and simply add my own electronics and belt drive system, but as luck would have it a gentleman was selling an Igus slider rail complete with belt drive and hand crank, and for only a third of the price he paid for it new ( never used it ). I wasted no time and bought that instantly realising how much work and time it would save me; ZLW-1040-02-B-100-L is the model number for those playing at home, with the optional hand crank.
Once I had the rail I started looking at options for adjustable legs or feet, thinking about modifying some existing legs from other sliders but the price to buy those separately was pretty bonkers really, so it was much easier and cheaper to make my own from scratch. I started with some aluminium box section, marked and drilled holes for mounting it to the bottom of the rail ( which has a handy T-slot ), and then purchased some threaded legs with self-levelling feet, along with some female knobs for setting the height & some female inserts for the threaded legs to screw into since the aluminium itself was too thin to be strong enough on its own. Two spirit level bubbles are included on the slider, one on the end and one on the carriage to aid with levelling the whole unit. The feet unscrew with one male knob ( teeheehee... ) on each which allows the slider to be placed into a much narrower bag for transport.
The carriage in standard form has no central mounting hole so I drilled a 10mm hole for the 3/8" inch bolt to pass through that the video head fixed onto. I also added a slab of aluminium to the front of the carriage that protruded slightly in either direction in order to actuate the micro switches that acted as limit switches for either direction. The video head itself is just a fairly cheap metal 3-way item so that I can angle the camera as I like and lock it in position- I don't intend to do clever panning shots as the slider moves along, otherwise I'd need a head that costs at least 5 times as much.
The Battery tray
The battery tray is another piece of aluminium box section that I cut one side off of with a hacksaw, and mounted it to the side of the rail with some plastic stand-offs and long bolts via another T-slot that runs down either side of the rails full length. I also attached a voltage checker for the Lipo battery that powers the drive motors, handy for checking remaining charge and preventing over discharge.
The Motors and gearing
To move the carriage I replaced the crank handle with a large steel MOD1.0 spur gear, which is driven by a DC brushed motor running through a reduction gearbox mounted on the end. There are two motors and gear boxes, one geared ( internally ) for high speed and one for much lower speed, 300RPM and 2RPM, and each one drives the spur through different pinion gears, resulting in either a ~10 second or 1 hour travel time for the carriage to reach one end from the other. To swap between motors, they are mounted to a sliding plate- up for one motor, down for the other -only one pinion is ever in contact with the spur.
The motors are controlled via a DC motor driver which features a variable speed control and polarity reversing, to allow fine tuning in speed and direction changing at the flick of a switch & twist of a dial. Only one motor is ever connected and to swap between them the leads are simply swapped over. The motors are wired in tandem with limit switches so that the slider shuts off once the carriage reaches the end of the rail in either direction- simply flip the direction reverse switch and it starts up again in the opposite direction. Long wires are kept tidy with small P-clips fixed to captive nuts in the T-slots running along the sides of the rail.
This was a fun project over the summer months of 2014 and the end result is a very capable motorised slider in a useful size that cost a fraction of what an off-the-shelf version would have cost with similar features. The only real downsides are the size ( it does partially dismantle for transport but the length is fixed at just over 1 meter ), the weight, and the noisy motor(s)- this isn't too much of an issue since any video or time-lapse photos taken with the slider will be combined with a separate audio track. Size and weight can be managed by transporting the slider in a bag once I find one long enough ( something for carp fishing rods or similar, or a tent bag maybe )- set up is very quick, and operation is very simple. Test footage will be uploaded to my Youtube channel once I get some time to do some practice shots with it.
I have done a little bit of testing, but bad weather and being busy at work have prevented me from doing all that much to get any real, decent quality test footage. That said, I decided regardless to address a few niggles with the design that will make it run even better when I do get the chance to use it.
Firstly, I replaced the noisy pinion and spur gears with a couple of pulleys that will reduce both noise and vibrations being transmitted to the camera.
I also decided to do away with the 2nd motor, since it was far too much hassle and too fiddly to adjust the motor mount to switch between them- it would be simpler to just remove the motor completely and change it for a slower one if required and use the same pulley; the speed controller is very handy to making both broad and fine adjustments to overall speed, funnily enough.
Finally, I am changing the location of the end-stops so that they cut power just before the carriage gets to either end of the rail, rather than when it gets there which results in a very sudden halt as the carriage does carry some momentum. That will prevent any potential for damage if the operator is using the slider at full speed and doesn't reduce it via the controller before they reach the end of the rail with the carriage.