Driving a brushless DC (gimbal) motor can be a pain in the transistors. [Ignas] has written up a nice article not only explaining how to do just this with an Arduino, but also explaining a little bit on how the process works. He uses a L6234 Three Phase Motor Driver, but points out that there are other ways to interface the BLDC motor with the Arduino.
A warning is warranted – this is not for the faint of heart. You can easily destroy your microcontroller if you’re not careful. [Ignas] added several current limiting resistors and capacitors as advised in the application note (PDF warning) to keep things safe.
Everything worked well at high speeds, but for slower speeds the motor was choppy. [Ingus] solved this riddle by changing over to a sine wave to drive the motor. Instead of making the Arduino calculate the wave, he used a look up table.
Be sure to check out his blog for full source and schematics. There is also a video demonstrating just how slow he can make the motor move below.
Continue reading “Driving A Brushless DC Motor Sloooooooowly”
Holding a video camera while shooting video can lead to finished footage that has some serious shakes. Lucky for us there are some solutions to this problem such as a passive steady cam stabilizer or an active motor-driven gimbal. [Oscar] wanted a smooth-operating brushless motor gimbal but didn’t want to spend the big bucks it costs for a consumer setup so he went out and built his own.
[Oscar] didn’t have a CNC machine or 3D printer to help with his build. He made his gimbal with simple hand tools out of plywood and hardware store bracketry. In his build post, he talks about how it is important to keep the pivoting axes of the gimbal in line with the camera lens and what he did to achieve that goal. The alignment of the axes and the lens ensures that the video is stable while the gimbal adjusts to keep the camera’s angle constant.
[Oscar] purchased the brushless motors and motor controller which included a gyro sensor on a separate PCB board. The gyro is mounted to the camera mount and sends tilt information back to the controller that then moves the brushless motors to keep the camera level. The final project worked out pretty good although [Oscar] admits he still would like to tune the PID settings in the controller a little better. Check out the video after the break where the stabilized camera is compared to one that is not.
Continue reading “Resourceful DIY Brushless Hand-held Camera Gimbal”
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”
[Joe] works in one of those fancy offices that has some… unique furniture. Including a swinging boardroom table. See where we’re going with this? [Joe] made his own coffee cup gimbal.
The gimbal itself is made out of solid steel, welded together for maximum durability. He first built it out of plastic to test the concept, but then quickly moved to the all-metal solution. It’s a 2-axis gimbal featuring very powerful brushless DC motors, capable of balancing even a light-weight DSLR — however we think balancing a coffee cup is much more entertaining. It does this with ease, even when sitting on the treacherous swinging boardroom table (of DOOM).
Continue reading “Auto-Balancing Gimbal Keeps your Coffee from Spilling”
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”
We’ve seen a lot of flying robots over the years, and for many of them, intimate contact with a stationary object would be a very, very bad thing. [The Laboratory of Intelligent Systems], at EPFL in Switzerland designed GimBall to not only take impacts in stride, but to actually use them as navigational aids. This is similar to an insect bouncing off an obstacle in nature.
GimBall’s design is a bit of a departure from the norm as well. Contra-rotating airplane propellers provide thrust while countering torque. It appears that the propellers are driven by two separate brushless outrunner motors, which would allow for yaw control via mismatched torque. Directional control is provided by a 4 articulated vanes on the bottom of the craft. Standard RC servos move the vanes. While not as common as quadcopters today, this “tail sitting” design has been around for decades. The Convair XFY “Pogo” is a good example of an early tail sitter design.
What makes GimBall so novel is its exoskeleton. A carbon fiber gimbal encircles the entire craft. Around the gimbal is a geodesic sphere made up of carbon fiber rods and plastic joints. The sphere acts like a shock absorber, allowing GimBall to harmlessly bounce off objects. The gimbal ensures that impacts won’t upset the craft’s attitude. Check out the video after the break to see how these two systems form an impressive shell which completely separates GimBall’s chassis from the outside world. GimBall can actually use its shell to “rotate” around obstacles.
Continue reading “GimBall Bounces off Trees and Comes Back for More”
Here’s [Tom Parker] showing off a brushless motor gimbal stabilizer for his GoPro camera. We saw a similar project a couple of weeks back that featured a 3d printed quadcopter mount. This offering is meant to be held in your hands. It keeps the subject in frame even if the cameraman’s hands pitch and roll (we figured aeronautical terms were best here). This image shows him demonstrating a level camera as he quickly rolls the frame from one side to the other. It doesn’t compensate for yaw, which is something he may change in the next iteration. We already like the results he’s getting with it.
About 3:15 into the video demo below we get a very quick description of the build itself. He started it as a project at University. Fabrication included work on a 3D printer, laser cutter, and vacuum forming machine. The grips are bicycle handlebar components. To overcome the stabilization system the operator has access to a joystick. Without this you’d never be able to aim the camera up or down because of auto-leveling.
Continue reading “Showing off a high-performance brushless motor camera gimbal”