# Weather Station Gimbal Support

I am currently designing a small weather station that will be suspended from two fiber optic cables and a power wire. You can imagine for now a three point attachment to each wire with a wind vane suspended below, like so. I need some help figuring out the best way to support it while allowing rotations.

Basically, I would like to be able to have the device adjust its pitch so that if one fiber gets pulled vertically, the wind vane will stay level. The yaw adjusted by the force from wind. I am not sure how important roll will be to add in, so for now I have not considered it too much. The reason for controlling pitch is that as the fibers are pulled up in the air, one may be

My basic idea now is to have a rod go through a small hole in the top part of the device, where the device can rotate, adjusting the pitch. You can see the 3 holes for inserting that rod; here is a video of the device. I would choose one nearest the center of mass (to be determined). For a sense of scale, those holes are about 1.5 mm in diameter. The whole device is small, and should be about 100-200g total.

I plan to have a clevis structure attach to that rod; what my fingers do in the video. After that it will have to go to an assembly above that will allow yaw rotation (not designed yet).

The problem I find with this design for pitch is there is no damping, so the device oscillates upon disturbances instead of finding an equilibrium point. Also, I have had some trouble finding rods and other parts at this size.

Any suggestions on how to best design this and parts that may be useful would be great.

Thanks!

(P.S. I tried putting the third image, but stack exchange limits me to 2 links until my reputation score is at least 10.)

• I've read the question twice and I think it requires some more figures and explanation for clarity. Is The vane mounted on another device? Is this device suspended from another mobile or stationary element, i.e. A house? Pitch / roll is not important for the wind direction. How accurate must it be? Etc. good question topic. – Gürkan Çetin Dec 18 '16 at 10:46
• Thanks for the comment, Gurkan. I added a video and a sketch. The vane is mounted on another device, the gimbal. The gimbal is attached to the three fibers/wires. The wires can move relative to each other; they should only be able to move vertically. That's why i want the vane to adjust for pitch and roll. Im not sure which accuracy you're asking about, but the pitch and yaw should adjust to within a ~3° of their ideal locations. – Alex K Dec 18 '16 at 18:11

First, the functional name of the asked mechanism is spherical bearing. Please have a look at https://en.m.wikipedia.org/wiki/Spherical_bearing

You can use a spherical bearing to allow continuous rotation (in yaw) while also allowing for some pitch.

Damping can be enhanced by inserting some sort of friction to the assembly.