The parts were ordered in Part 1, the quadcopter was assembled in Part 2, and in Part 3 I covered the steps I followed to set up the quad for its maiden flight. In part 4, I showed how I tuned the quad’s PI settings to optimize its flying capabilities. Now, in Part 5 I will cover how I attached a GoPro camera to the quad to get some video from the air.
Amateur Aerial Video
Though I’m not an expert on aerial video and photography, small lightweight cameras like the GoPro Hero 2 make it easy for an amateur like me to capture quality HD video from the air. I built this quadcopter with the idea of being able to make aerial HD videos which I will cover in this blog post. Professional aerial photography and first person video(FPV) are beyond the scope of this post.
Many multicopter enthusiasts use GoPro cameras to film their videos and take photographs. The GoPro 3 is their latest camera and has amazingly high resolution. I own the last generation GoPro 2 and this post is about making it work on my easy DIY quadcopter, but I believe the same information would apply to the GoPro 3. GoPro no longer sells the GoPro 2, but they can be found on ebay.
The HobbyKing 720p wing camera, 1080p wing camera or 1080p ExplorerHD might be good lower cost alternatives, though I haven’t tried any of them. Many folks even use inexpensive keychain cameras with ok results.
Filming basic aerial video is fairly simple. All it requires is mounting the camera in a location where the props and landing gear are not in the frame of the camera, stabilizing the camera to reduce the jello effect, and protecting the camera from crashes.
Continue reading to see how I used my quad to film aerial video…
Camera Mounting Location
Attaching the camera to a location where props, arms, and landing gear are out of view sounds simple enough, but can be a bit tricky. If the camera is located at the same level or above the arms of the frame, the props inevitably end up in the frame. One solution is to use a frame that positions the front arms at a wider angle to keep them out of view. Many FPV frames are designed this way, but they tend to be trickier to balance and tune due to their lack of symmetry. Another solution is to attach the camera to a rail that extends beyond the view of the props. Again, balancing can be tricky since there has to be weight in the rear to offset the weight of the camera.
The easiest solution is to mount the camera below the quadcopter and out of view of the props. This requires a tall landing gear to prevent the camera from being impacted on landings. That is why I chose the H.A.L. quadcopter frame. It is fairly simple to attach my GoPro 2 in a position where neither the props or the landing gear are in the frame of the camera. Also, by positioning the battery parallel to the camera at the rear of the center plate, the quad stays well balanced with the center of gravity in the center of the frame. On the downside, frames with tall landing gears are a bit less aerodynamic.
There are entire threads on RCGroups dedicated to camera stabilization methods and they make for some good reading. The most common stabilization problem is called the “jello effect” which is caused by motor and prop vibrations traveling through a frame. Video with a bad jello effect is not fun to watch and can makes me a little woozy.
Some say the best way to avoid the jello effect is to balance the motors and props perfectly to eliminate the vibrations in the first place. The balancing process involves placing small pieces of tape on the props and motors similar to the way tire weights are used to balance tires. There are many videos on youtube that demonstrate using prop balancing tools and lasers to balance props and motors.
I am too lazy to keep my props and motors balanced especially since I crash so often. If the vibrations get too bad, I either replace the prop or the motor. So, I had to find a way to mount my camera to minimize the jello effect vibrations in my GoPro 2 videos.
I considered four possible ways to mount my GoPro 2:
A servo driven camera mount or gimbal
Camera gimbals are servo driven devices that are usually controlled by the flight control board. The stabilization firmware in the flight control board uses the servos to keep the camera smooth and level and independent of the quads jerky movements. Most professional aerial videographers use gimbals, but have never used one. They definitely add a level of complexity and weight. Interestingly, there is a servo driven camera mount that HobbyKing sells for this quadcopter. I bought this, but it is fairly complex to assemble and I haven’t had time to try it out yet. Another issue when adding a gimbal is weight. A more simple and lighter servo driven camera mount designed specifically for a GoPro 2 is sold by DIY drones and may be a better choice, but would probably require some DIY work to attach it to the frame. Given the complexity of this mounting technique, I decided to use a simpler method.
The mount that comes with the GoPro 2
The GoPro 2 camera comes with its own protective case and mount. It is a good idea to use this protective case because crashes can easily ruin a GoPro 2, especially when mounted underneath a frame. The GoPro 2 case is probably the best way to protect the camera. Unfortunately, the sticky mount that comes with the GoPro 2 doesn’t fit or stick very well to this frame, so I decided to make my own DIY mount to attach to the GoPro 2 protective case which I describe below.
Making a DIY mount
There are holes all around the center plates of this frame that are used to attach the protective lid. I decided to use the front center hole to screw in my own custom GoPro 2 mount. It is nothing fancy and was very easy to make. I found a small piece of aluminum U-Channel that was the perfect size to fit the mounting bracket of the GoPro 2. I also happened to have some 3mm screws and lock nuts, so I drilled a 3mm hole in the top and side and used it to attach the GoPro 2. Unfortunately, since this mount is not shock mounted in any way and is attached directly to the frame, the video I recorded using this mount had lots of jello effect. Also, the GoPro 2 case adds a lot of extra weight. Here is a short video using my DIY mount where you can see the awful jello effect:
Attaching the GoPro 2 directly to the quad.
Crazy as it may sound the simplest approach of zip tying the unprotected GoPro 2 to the frame against a piece of shock absorbing material gave me the best results. It may not look pretty, but it works! I used a piece of Sorbothane under my GoPro 2 to reduce the jello effect, but there are plenty of other materials that would also work and are discussed in the RCGroups thread. The downside of this approach is that it leaves the camera completely exposed and vulnerable to being ruined in a crash! Here is a short video made with the GoPro 2 mounted against a piece of Sorbothane with a zip tie with much less jello effect:
Protecting the Camera
As I mentioned above, the best way to protect a GoPro 2 is by placing it in the protective case that comes with it, but this makes it more susceptible to the jello effect. A great compromise is to protect only the lens, which is the most likely part of the camera to be damaged in a crash. Here is a link about making a DIY lens protector. Also, getfpv.com sells a product for the GoPro 2 called the LayerLens. They also make the LayerLens for the GoPro 3.
As you can see, from my pictures, I am still flying with an unprotected lens which is not very smart considering I have already ruined one GoPro 2 camera!
Now, a bit about what this post didn’t cover…
First Person Video
Many multicopter enthusiasts enjoy first person video flying. This involves connecting the video feed from a camera mounted on the multicopter to a transmitter that sends the video back to a receiver on the ground allowing the pilot to view the live video feed as if they were in the cockpit of the multicopter. Usually, the video is viewed by the pilot either through special video goggles or a hooded video monitor. This is beyond the scope of this post, but the GoPro 2 camera does have a live video feed and can be used for FPV by purchasing the necesarry add-ons.
Professional Quality Video
Professional aerial videographers who use higher end DSLR cameras and even expensive movie cameras. These cameras require much larger, very expensive multicopters and camera gimbals to stabilize the video and carry their valuable cargo and are well beyond the scope of this article.
There are many levels of quality when filming aerial video. Though not anywhere near the level of professional videos, I am happy with what I can achieve by zip tying my GoPro 2 to my quad against a piece of Sorbothane. Excellent flying skills, shot setup, video editing and scenic views also contribute to great video, none of which I can demonstrate at this time, but I’m working on it. One technique that is fun and easy and requires very basic flying skills is to walk behind a quad while piloting and filming. I used this technique in the above videos. The nice thing about flying this way is that the nose is always out making the quad very easy to control.