Obviously Software Defined Radio is pretty cool. For a lot of hackers you just need the right project to get you into it. Submitted for your approval is just that project. [Simon Aubury] has been using a Raspberry Pi and SDR to record video of planes passing overhead. The components are cheap and most places have planes passing by; this just might be the perfect project.
We’re not just talking static frames with planes passing through them, oh no. Simon used two hobby servos and some brackets to gimbal his Pi camera board. A DVB dongle allows the rig to listen in on the Automatic Dependent Surveillance Broadcast (ADS-B) coming from the planes. This system is mandated for most commercial aircraft (deadlines for implementation vary). ADS-B consists of positioning data being broadcast from planes using known frequencies and protocols. Once [Simon] locks onto this data he can accomplish a lot, like keeping the plane in the center of the video, establishing which flight is being recorded, and automatically uploading the footage. With such a marvelously executed build we’re certain we will see more people giving it a try.
[Simon] did a great job with the writeup too. Not only did he include a tl;dr, but drilled down through a project summary and right to the gritty details. Well done documentation is itself worth celebrating!
Continue reading “Keep Tabs on Passing Jets with Pi and SDR”
We’ve all prematurely stopped watching some Youtube video because of shaky camera work that makes the video unwatchable. There is a solution available for this problem, it’s a device called a camera stabilizer and it is designed to compensate for jerky camera movement. There are several types available for purchase but they can get fairly expensive. Even the cheaper ones at a few hundred dollars are not economical for hobbyists. [John] set out to make his own camera stabilizer using some unorthodox parts.
[John’s] chose a gimble style design that effectively lowers the camera’s center of gravity down close to the camera persons hand. The handle of the device must also be mounted in a manor to prevent angular and rotation movement of the supporting hand from transferring to the camera.
The handle is from a cement trowel, on top of which is a ball bearing mounted to a threaded rod. A PVC fitting was heated to soften it and the bushing pressed in. This bearing is responsible for allowing the rotational freedom between the handle and the camera. To decouple any angular movements, two hinges were attached to the PVC fitting. The hinges are perpendicular to each other, one allows forward-back tilting while the other allows left-right tilting. The upper hinge is attached to a piece of poplar wood that also serves as a base for the camera.
At this point, if you were to try to hold this contraption with the camera installed, it would immediately tip over due to gravity. To prevent this, the center of gravity of the moving parts (including the camera) must be lowered. [John] did this by using some aluminum tubing to support wood weights that reside lower than the pivot points created by the hinges.
If you like the DIYer-style stabilizers, check this other wooded one out. Want something more polished looking? How about this pistol grip stabilizer?
After the first flight of your newly built multi-copter, you will immediately want to add a camera. This sequence of events follows the laws of physics and is as predictable as gravity. Just strapping a camera on by way of a fixed bracket may technically solve that problem, but it creates another. A multi-copter tilts and rolls as a result of changing flight direction. If the multi-copter tilts and rolls, so does your camera. This is where a gimbal comes in handy, it adjusts the camera in an equal and opposite direction than that of the aircraft. If the aircraft tilts forward, the gimbal tilts the camera backward the same amount. The result is a steady camera for capturing some sweet videography.
Team SSG over at rcgroups.com has come up with what they are calling the Super Simple Gimbal. Their vision was a gimbal that would be inexpensive, easy to build and add minimal weight to the aircraft. On a normal gimbal, there are two motors or servos, each one specifically controls a single axis of movement. On the SSG, there are 2 servos but they do not move independently from one another. The camera is mounted to a plate that is supported on one end by a piece of silicone tube which becomes a fulcrum for the system. The other side of this plate is supported by 2 linkages (also made of silicone tube) that are themselves connected to the servos. If both servos move up, the camera is tilted down. If the right servo moves up and the left down, the camera is tilted to the left.
Continue reading “Super Simple Gimbal For Multi-Rotor Aircraft Laughs In The Face Of Complexity”