Intro: Gyroscopic Gopro Mount/ MotoGP Style
I am a motorcycle rider and as any rider I want to know and to show/record how much angle I can take. One option is to look at your tire chicken strips but it is not really relevant to your friends . Another option is a gyroscopique camera as in motoGP. The camera stays horizontal once the bike take a corner.
So I tried to build a cheap and mechanical Gopro gyro mount that I can fix on any Gopro pad with any angles (suspended, tilted...).
The gyro system is based on a pendulum using simple bearing. The advantages are : it is really cheap compared to commercial system or electronic system and you do not need battery. It is good nowadays to have something which runs without batteries!
Step 1: Grab All the Necessary Stuffs
Let's grab all the necessary stuffs!
First of all, you need of course a Gopro, a basic Gopro quick release mount and a Gopro pad. I took the "free" pad from the Gopro's box (cf picture) because there is a hole just behind the pad and we could custom it later ;) .
For the pendulum system I use a free bearing from a old hard drive.
You just have to open up the hard drive, remove the disk from the bearing. It is free and very small ,light and efficient.
The weight, the stiffness and the center of gravity are crucial for camera recording and for the pendulum based gyro cam.
The heaviest and the stiffer the system is the more stable it will be.
For a given mass the further it is from the center of rotation of the bearing system the faster it will go to the equilibrium position (for the suspended mass), so at the horizontal.
But, in another hand, the higher the center of gravity is the bigger vibration will be.
The conclusion is that you need to have the suspended mass (so the Gopro) as close as possible to the fixation point on the motorcycle and at the same time far from the center of rotation of the bearing.
The last but not least :
You need the famous piece to link the bearing system to the Gopro mount that will be fix on your motorcycle pad.
Referring to the weight and the center of gravity's discussion this piece is crucial. It needs to be stiff (to reduce the vibration) and long enough for the pendulum to work. But not too long to keep the center of gravity close to the fixation point. The best will be something stiff and light at the same time as aluminium or PLA. I designed the ideal piece for this gyro system but as I have not a 3D printer I have done in another way. For those you are interested I join the Sketchup file.
For those who as me do not have a 3D printer, I took lens mount from Thorlabs for exemple. For my bearing I used a LMR20 (20mm of diameter) with a stainless steel post TR2 (50mm long). This is not compulsory and it might not fit with your bearing. Feel free to share other ideas :) . I was stuck for a long time...
Step 2: Let's Put Together All the Stuffs
The "free" pad has a hole behind it that fit almost the biggest round part of the bearing system (the one fixed to the frame of the hard disk). It will then simplify our work. You just have to glue the two part together with epoxy.
If you are scared that the glue is not enough you can add bolts and nuts to the "free" pad . You just have to drill holes in front of the existing holes on the bearing system. That one advantage of using the "free" pad, you have space to add some additional stuffs.
You have to glue the lens mount to the other part (free to move) of the bearing system.
If you use a 3D printed piece, you can either glue it or drill holes that fit the existing holes that were fixing the disk.
One of the last thing to do is to fix this piece to basic Gopro mount. As I am using my steel post, I drilled a hole on the mount (cf red cross on the picture) and used a headless screw to assemble the two parts. the hole should be a little bit smaller than the screw in order to fit perfectly and then to have no slack between the two parts. It will help to reduce the vibration.
If you use a 3D printed piece, you have to skip this step as the piece is made to fit on any mounts :)
Fix everything together. You have to tight every screws to limit the vibration. Once again if you are scared to loose your Gopro you can glue every pieces or add thread-locking fluid.
Cut all the unnecessary parts of the free mount. I kept the lower part if I need to add some weight.
Step 3: Test
For the moment the pendulum is not really well balanced. To avoid oscillation you should increase the damping of the system and add some weights behind the Gopro to increase the suspended mass and then decrease the time needed to go a the equilibrium position. To increase the damping I will try to put an elastic band between the two parts of the bearing system.
Where I am impressed is the vibrations. There is none! The whole system is really stiff. But I was not expecting so importante oscillation...
Hope you will enjoy it.