Introduction: GoPro Cable Cam: Wheeled Camera Suspension System
The cable cam is a trolley system to support a video camera and runs along some kind of cable.
I saw a lot of ideas and instructions for various types of cable cams for the GoPro or standard cameras. The beauty of the GoPro is you can mount it upside down and set it to flip the video. Saves the time and trouble of flipping it in editing software.
Anyway, this is my shot at making one with the items that are easy for me to find around my garage or buy from Home Depot or the local hardware store. I figured I would select the cable materials and then go from there with the trolley wheels, and then move on from there.
Step 1: Cable
I investigated numerous types of rope and cable. My criteria were that the cable be inexpensive, strong, light weight and small (pack compactly).
I decided to use paracord (also called parachute cord or 550 cord). It is readily available from numerous sources. Paracord is approximately 5/32" or 4mm in diameter. There are different grades and strengths. Grade III has a 550 lb. strength, hence the name 550 cord. There are a lot of paracord out there that are not 550 cord.
I bought 100 feet from a nearby army navy store for about $8 to get the project moving. It is not 550 cord. It is a bit stretchier than I would ideally like to use, but cost outweighed that aspect.
Now I will invest in 300 feet of real grade III 550 cord from the internet and see how that compares to what I have been using.
I tie a rag onto the cable before the abrupt stop at theend to slow down the camera
Step 2: Trolley Wheels
I first tried out some sliding screen door pulley wheels. They were cheap, small and fit the cord. They did not roll freely due to the heavy grease, so I heated them up and drained out the melted grease. I then lubed them with some thin bicycle lubricant. They rolled fine, but i was getting some chatter in the middle of the run, so I decided to shift gears on the wheels.
I saw somewhere on the internet where someone used skateboard or rollerblade wheels. They said the held a hot metal rod on the wheel to make the groove. This did not work for me on either skateboard (plastic) or rollerblade (urethane) wheels.
I opted for skatebaord wheels since old one are readily available for free. I did steal a set of my sons new bearings, but I probably paid for them anyway.
I decided to route grooves in the skateboard wheels using a router table set up with a 1/4" half round bit. I just kept my fingers as far away form the moving bit as I could. The groove was not completely even, so I tried using a round file by hand. This worked somewhat. Then I figured I could secure a bolt through the wheel and put it in my drill press. I did this and held the round file and then sandpaper on a screwdriver shaft up to the groove. This worked great.
Step 3: Body/Frame/Carriage
I used a piece of 2 x 4 wood for the body of the rig because I wanted something almost as wide as the wheels and it is easy to work with and shape to the form I wanted.
The exact size and configuration is not important. For mine, I left the ends taller to give more space for attachment of the wheel support brackets, using two through-screws. I cut down the height in the middle to provide clearance beneath the cable and allow space for accessories like the camera mount screw and the brake.
Step 4: Wheel Support Brackets
The wheel support brackets are 4" pieces cut off a 1/8" x 3/4" aluminum flat bar from Home Depot. You could use any available strip of metal, like a duct hanger strap, flattened copper pipe, etc. You could probably even use a piece of that Lexan now that I think of it.
I taped the pieces together for drilling so the holes would align.
Two smaller holes for the #10 x 2 1/2" machine screws securing the brackets to the body and one 5/16" hole near the top for the 5/16" x 2 1/2" axle bolt.
On one side I cut a slot in the side of the bracket to allow it to swing on and off the axle bolt to allow the rig to be mounted onto or removed from the cable while it was strung between its supports. I cut the upper of the two machine screws short after securing with washers and nut in order to allow the bracket to rotate on only the bottom bolt.
The lower bolt was packed out with extra nuts and washer to make up the required width of the wheel assembly and allow the bracket to swing past the cut screw above it.
Step 5: Mounting Wheel on Axle Bolt
Secure the axle bolt to the fixed bracket using a 5/16" jam nut. The jam nuts are a little thinner than the normal nuts and allowed a little more play in setting up the wheel on the axle.
I flattened several 5/16" lock washers to use them as spacers between the nut and the wheel bearings. Normal 5/16" cut washers were too big in diameter, but the lock washers were the right size. Use just enough to keep the wheel from rubbing against the bracket.
Next slide the wheel onto the axle and then place more lock washer spacers over the wheel. You will need to figure how many based on the nuts that go on next. I only need one lock washer spacer this side.
Next comes a standard 5/16" nut and then a 5/16" jam nut. You might be able to use standard nuts instead of jam nuts, however, I was trying to keep the overall width of the wheel assembly as narrow as possible.
lastly, a 5/16" washer and 5/16" wing nut to engage the swinging bracket.
Step 6: Camera Mount and Brakex 5"
I drilled two 1/4" holes vertically through the body.
The first hole was to hold the 1/4" - 20 thread x 5" bolt for the camera mount. This was secured with a washer and 1/4" nut. A 1/4" wing nut secures the GoPro tripod mount to the bolt in the desired position.
The second hole was for an additional 1/4" x 5" bolt that was inserted into a hole drilled through a small section of 1" diameter wood dowel. The bolt head was recessed into the dowel and the edges smoothed with sandpaper. This bolt was secured to the dowel with a 1/4" nut and then a 1/4" wing nut was added before inserting the bolt through the body. A second 1/4" wing nut was added beneath the body. These two wing nut allow this brake assembly to be easily raised and lowered. If the cable is set up on a steep incline, the brake can be applied to slow the descent.
Step 7: Cable Cam Test
I just shot two quick videos showing the test runs.
First is a shot of the cable cam running down the cable.
Second is a shot from the GoPro on the cable mount itself.