Building a Pro Camera Crane / Jib, part 1

I was once told that my favorite interest seemed to be collecting hobbies. That may be truer than I'd like to admit, and for the last six months I've added yet a new project to all my previous (unfinished) tinkerings.

I have a Basic Stamp micro-controller and USB programming board left over from another project that I never finished. One day I realized that a fun use for it would be to build a joystick-controlled pan/tilt camera head that could be placed on the end of a camera crane.

After 30 minutes with a search engine I realized that buying a ready-made crane was out of the question, as the ones I found cost several thousand dollars. Working at a TV broadcaster I have first-hand access to professional jibs and saw that they weren't as mechanically complicated as I had initially thought. I imagined the hard part would be controlling the camera head with a joystick. As the build have progressed I have come to understand that I had seriously underestimated the amount of mechanical work required.

My initial plan was to built a jib with a total length of 3 meter, based on that I found two light and sturdy metallic pipes (25 mm in diameter) in a local hardware store. These would be used as a parallelogram so that the camera head would always be vertical no matter how the jib was raised or lowered. With an arm of that length it would also be easy to fit the jib inside a car.

As the project has progressed I've abandoned these pipes for two reasons. Firstly I've found it hard to fasten the six ball-bearings to these pipes, since they aren't very sturdy and I wouldn't be able to make holes in them without weakening them too much. And secondly, I got megalomania and realized I wanted a longer arm that could still be stuffed into a car, so I decided to abandon the cheap pipes and go with two 3 meter long pieces of rectangular aluminum tube that could be assembled into a 5 meter crane. An added bonus is that the length of the arm can be shortened if necessary.

Using a single arm means that I need to use two pulleys with a wire between them. One pulley will be fastened to the camera head and the other to the tripod mount.

Without a sturdy tripod as a base, the jib would become wobbly and unstable. Luckily I found a great Manfrotto tripod with a fluid video head and detachable dolly wheels on Swedish ebay. You can't complain about the price: $200 including shipping!

To attach the arm to the tripod I've bought a heavy construction bracket used for securing wooden beams. All I had to do was to chop off the protruding flanges and drill a hole for the tripod mounting screw. I'll even be able to use the pre-drilled holes to fasten the axle!

The controller is housed in the clear acrylic case from an iPod Shuffle and is made up of a 9V battery, a Basic Stamp BS2p24 and a Pololu DC Motor Controller. Power to the motors come from an external 6V lead-acid battery that will be used as part of the counter-weight on the arm. The joystick is from a Sony PlayStation 2 and I'm using three potentiometers that will be used as separate pan and tilt speed adjustments plus a zero-point sensitivity adjustment. The code is still pretty rough, but I've added a routine that sets the zero-point of the joystick at boot time. I'll publish the source-code when everything is working, if anyone's interested.

As a camera I'm using my Canon HV-20 with a RedRock Micro M2 lens adapter with a used follow-focus (thanks to ebay again!) Unfortunately the HV-20 doesn't have a LANC port so I'm using a 5 meter long optical fiber to send the IR remote signal from the back of the jib. A bit of a hack, but this is a rebel-style jib after all!

Yes, I know that with only one joystick I don't yet have focus control, but based on previous experience I've chosen to complete version 1.0 before adding any more features. The motor controller can only be connected to two motors, but with my follow-focus I can easily attach a servo to the gear and control that directly from the Basic Stamp.

- So what will it be used for? you ask. Well, now we get into serious denial-territory. I've tried to justify the time and money spent so far with being able to sell really cool shots at iStockPhoto from our upcoming trip to the Norwegian coast , but lately I've come to terms with the fact that I just need the challenge.

I'll keep posting with more pictures as I get closer to final assembly!

- Jonas