LASS L-Angled Small System
Subtitle:"Don't get mad, get even!"
David Hunt - Gray, Tennessee, USA March 26, 2000
THE BRAINSTORM
About a month ago Simon Harbord started a new evolving project on his web site (see LINKS page). The project entitled "Build A Basic Rig" is about a third complete as of this writing. It chronicles the development and building of what Simon calls, "a radical minimalist rig." Simon is a fountain of original thinking in the field of KAP. I once accused him of being the Renaissance Man of the KAP community. BUT... this "radical minimalist rig"... I had this idea over a year ago!!! It's true that I never attempted to build it, and it's true that I never published, BUT...Let me digress, this isn't the first time that an "original" idea of mine has been appropriated. Just this last year I had the highly original idea of building a foil kite filled with Helium. It was a superb bit of thinking that was going to revolutionize kite flying, turn the KAP community on end, and probably revitalize the Helium industry. Just a few months ago I ran across an old out-of-print kite book that had a picture of just such a kite. I was devastated, with the book being out of print I was unable to write to the publisher and have them give me credit in the next printing.
I could also mention the paper airplane design that was stolen during the 2nd International Paper Airplane contest, or the idea that many of you from the USA know about...I was the guy that gave Al Gore the idea to start the Internet.
So, when I heard about this "radical minimalist rig", I told myself this has got to stop. I'm tired of my intellectual property being abused.
I hope you see that I'm not really mad with Simon for this great idea, but I am going to get even. And how better to get even than to build my own minimalist rig using one of Simon's discarded ideas and name it LASS.
THE IDEA
Simon's "lateral thinking" led him to make the following comments in the early stages of developing his "radical minimalist rig"If you glued two servos together and mounted the camera directly on the output shaft of the tilt servo, while suspending the system from the output shaft of the pan servo what would you get? Well, of course, the answer is you would get a system for badly straining the tilt servo's gears, something with no inherent balance.
Simon included the following conceptual 3D rendering:
©2000, Simon Harbord I began thinking about ways to solve the balance problem with Simon's two servo "Block" setup. All the arrangements that I could come up with, where the Pan and Tilt Servos were assembled as a single block along with the Receiver and the Battery, had problems with the overall balance. The balance problem was then approached with the idea of creating the most compact arrangement of components but not necessarily in one block. My solution was to use a short length of 3/4" aluminum angle, 1/16" thick. This little piece of metal moved the Pan Servo up and over the camera. The Tilt Servo, Receiver and Battery would remain together as a block, and the Pan Servo would hang off the other end of the L-shaped angle stock. Fine tuning the balance could be achieved by proper placement of the Receiver and the Battery when attaching them to the Tilt Servo. The new concept looks something like this without the Receiver, Battery, and Shutter Servo:
©2000, David Hunt
Simon's second concern was with the stress placed on the Tilt Servo gears when the camera was suspended off the end of the servo shaft. My thinking was that it would take the same amount of torque to tilt the camera with one pivot point as it would with the traditional two pivot points (+/- a little extra friction caused by lateral torque on the output shaft). Thus the stress on the gear teeth inside the servo would not be much different than normal.
(MORE TORQUE CONSIDERATIONS -because the axis of the tilt rotation does not pass through the center of gravity of the camera on the LASS rig, more torque is required to tilt the camera than on a normally balanced rig. As long as the increased torque does not exceed the torque listed for your servo, the servo should be able to tilt the camera without undue strain)
A potential problem could come from the lateral torque on the output shaft of the Tilt Servo and its supporting structure. This would cause higher than normal stress on the surfaces that support the output gear. This increased stress could lead to premature failure or excessive wear of these structures. I figured that using the lightest camera possible would make this workable, the Olympus Stylus Epic. If the servo gave me trouble after a few uses I could always use a servo with bearings, and on the off chance that the gear teeth showed signs of wear then there are servos with metal gears, or higher torque, or both.