DIY Video Transmitter Turned WiFi Jammer

August 27, 2022 by Danie Conradie 31 Comments

The proliferation of FPV drones has brought a flood of cheap wireless video tech. After flying and crashing a cheap FPV drone for a bit, [GreatScott] decided to try his hand at building his own video transmitter, which turned out to be a lot harder than expected.

While digital technology has caught up to the FPV world, a lot of systems still use analog video, especially for drone racing. The video quality isn’t great, but it has the advantage of very low latency. The technology is very similar to the old analog TV broadcasts, but mainly uses the 5.8 GHz license-free bands. It is essentially analog video signal, frequency modulated onto a 5.8 GHz carrier signal transmitted through an appropriately sized antenna.

After a brief failed experiment with a simple circuit built from discrete components, [GreatScott] turned his attention to voltage-controlled oscillators (VCO). He bought a couple of 5.8 GHz VCOs from Aliexpress, and created and used a simple opamp circuit to boost the FPV camera video signal to the required input level for the VCO. This failed to produce any identifiable image on his video receiver goggles. In an attempt to confirm that the VCOs produced the desired frequency, he ordered a similar 2.4 GHz VCOs and built a short range (20 cm) WiFi jammer. With a signal generator to create a simple input signal, and confirmed that it interfered with his laptop’s WiFi connection.

After more experimentation with other VCOs, the closest [GreatScott] came to success was a barely identifiable image transmitted using a Maxim 2.4 GHz VCO. If you have any ideas on what is missing in the VTX circuit, drop them in the comments below.

Building RF circuits that interfere with the legitimate signal around you, or broadcasting out of band, is generally not a great idea, and could earn you an unpleasant visit from the authorities. If you want to build your own digital video transmission, take a look at the Wifibroadcast project.

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Drone Filming Chile’s Urban Bike Race Takes Some Fancy Radio Gear

April 27, 2022 by Lewin Day 13 Comments

Drones have revolutionized the world of videography in perhaps the biggest way since the advent of digital hardware. They’re used to get shots that are impractical or entirely impossible to get by any other means. The [Dutch Drone Gods] specialize in such work. When it came to filming an urban mountain bike race in a dense Chilean city, they had to bust out some serious tricks.

The FPV video feed was grainy, but good enough to keep the pilot on track. The drone carried a separate second camera for capturing high-quality footage of the run.

Typically, running a drone chase cam behind a biker would require some good first-person flying skills and a quick drone. However, for the Red Bull Valparaiso Cerro Abajo urban downhill event, this alone would not be enough. The tight course winds down staircases between thick concrete walls and even through houses, presenting huge challenges to maintaining signal integrity. Without a clear video signal, the pilot can’t fly the drone without crashing.

To make this all possible, the team used a variety of techniques to help combat the uncooperative radio environment. Directional antennas were used to target different sections of the course. Additionally, a second drone was flown high above the course carrying a radio repeater, helping provide a better line-of-sight contact to the camera drone following the riders when the buildings would otherwise block the signal to the pilot.

Even with all this work, the signal was still scratchy and would cut out at some points. However, with a bit of blind faith when cutting through the worst areas, the [Dutch Drone Gods] and the [Red Bull] team were able to put together an amazing FPV drone shot shadowing [Tomas Slavik] on his run down the extremely difficult urban course.

Details on the precise hardware are scarce. However, it’s something that any experienced drone builder could probably whip up without too much trouble. The idea of using a drone-based repeater is particularly exciting, and something we’re sure could help out many pilots who find themselves operating in difficult urban environments.

We’ve seen plenty of great FPV stories over the years, from early experiments in the 1980s to fun DIY cockpit builds of today. Video after the break.

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A Simple 3D Printed Rover Design

February 10, 2022 by Lewin Day 4 Comments

There are plenty of RC cars and robot platforms out there that you can buy. However, there’s an understanding that’s gained from building your own rover from the ground up. Which is precisely what [Alex] got from developing this compact 3D printed rover design.

The design is by no means fast; it’s intended more for crawling around “at a slow deliberate pace” as [Alex] puts it. Off-the-shelf 12 V gear motors are used to provide plenty of torque to get around. The modular design means that it can be built with just wheels, or set up with tracks fitted for additional performance in softer terrain. Skid steering is used to turn the platform.

Fitted with a Raspberry Pi Zero 2W, the rover can be controlled remotely over WiFi. A separate FPV camera and transmitter is then used to stream video remotely to pilot the bot. However, if you’re so inclined, you can probably use the Raspberry Pi to stream the video, too.

It’s a fun build and a great way to learn about building rovers and robots that move. We’ve seen some other interesting tracked rovers before, too. Video after the break.

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Neat Little Airboat Built From Old Drone Parts

September 2, 2021 by Lewin Day 3 Comments

Multirotor drones tend to need quality and well-matched parts in order to stay balanced and in the air. However, crash enough drones and you might find you’ve got plenty of mistmatched bits and pieces lying around. In just this vein, [Jason Suter] decided to raid his junk box and built himself a little FPV airboat using spare parts.

The airboat consists of a 3D printed hull, paired with a separate power module. The power module houses the flight controller, and mounts twin motors on the rear. Fitted with three-blade props, they propel the boat and allow it to be steered with differential thrust instead of a rudder. It’s then fitted with a camera to allow it to be piloted with an FPV headset.

Handling still isn’t perfect, and water on the FPV antenna causes some issues with video transmission. However, it’s a fun project that makes good use of old parts. Of course, if you’re having vibration problems with your own FPV projects, consider building a vibration-absorbing mount. Video after the break.
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Building A Quick And Dirty RC Mower With FPV

May 21, 2021 by Lewin Day 4 Comments

Mowing the lawn can be a tedious job. Tired of the effort involved, [i did a thing] decided to enlist the help of [Makers Muse] to build a radio controlled mower instead to make the backyard chore a little more interesting. (Video, embedded below.)

The mowing itself is done by a typical push-along garden mower with a gasoline engine. However, it’s fitted with twin DC gear motors harvested from a mobility scooter. The mowers original front wheels were also removed, replaced with casters from the same mobility scooter that donated the drive train. Off-the-shelf speed controllers were then used to run the motors, and hooked up to an RC receiver. The mower could then be steered via a radio controller set up with mixing to enable the twin-motor setup to steer and drive.

An FPV camera was then fitted on the front of the mower, sitting on a stack of kitchen sponges that act as a isolator to negate the effects of the engine vibrations on the camera. The result is a relatively smooth video feed, allowing the operator to sit at a comfortable distance and control the mower via radio and goggles.

It may not be the most effective way of trimming the lawn, but it does look like a fun project, and sometimes that’s all that matters. Of course, you could always upgrade to a fully autonomous mower instead.

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Vibration Isolation Helps Improve FPV Video Feed

March 25, 2021 by Lewin Day 7 Comments

First-person view technology has become hugely popular in the RC community, letting the user get a vantage point as though they were actually within their tiny scale vehicle. It can be difficult to get a good, clean video feed though, particularly in models that have a lot of drivetrain vibration. [Engineering After Hours] decided to tackle this problem with a simple vibration isolator design. (Video, embedded below.)

The first step is to analyse the vibration to get an idea of the frequencies that are most important to target. WIth that done, a simple 3D printed camera mount is designed with three flexible joints between the camera and the base which is rigidly coupled to the RC boat or car’s body. The modal analysis tools in Fusion 360 were used to get a rough idea of the frequency response of the system, helping to get things in the ballpark with a minimum of fuss.

The final design does help cut down on vibrations, though it is unable to counteract heavy vibration from driving on extremely rough surfaces. In these cases, [Engineering After Hours] recommends the use of a gimbal instead. Proper damping can be a godsend in many applications; bricks can make a huge difference for your 3D printer, for example.

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High Speed Flight In A Homebrew FPV Cockpit

March 19, 2021 by Lewin Day 13 Comments

First-person view, or FPV, has become hugely popular in RC flying circles. A pair of video goggles lets the pilot fly with vision from the plane itself. To make things even more realistic, the team at [FliteTest] built a replica cockpit with working controls and took it down to the field for testing. (Video, embedded below.)

Since the pilot is wearing video goggles, aesthetics aren’t the key here. A RC transmitter was gutted for its gimbal and potentiometers. The former fitted with a long stick for aileron and elevator control, and the latter hooked up to pedals for the rudder. There’s even a proper throttle handle. It’s a low-budget build, with PVC pipe and bungee straps doing much of the work, but that doesn’t detract from the fun factor one bit. The team later upped the stakes, flying a faster model with the rig at speeds up to 120 mph.

Interesting to note is the somewhat visceral reaction by the pilot when crashing, as the combination of first-person view video and realistic controls gives a powerful sense that one is actually in a real plane. FPV flying actually has a longer history than you might expect, with roots as far back as the 1980s. Continue reading “High Speed Flight In A Homebrew FPV Cockpit” →