Calling themselves Los Ferronautas (or "railanauts"), Ivan Puig and Andrés Padilla Domene documented the impacts of the privatization — and subsequent immediate closure — of Mexico's passenger rail lines. Their home-built vehicle could travel on the rails or on the ground, from Mexico City to the Atlantic.
I know you've seen the videos on YouTube, stunning coastal fly-overs, or fast and low runs through parks and forests, dodging trees like speeder bikes on the Endor moon. If you don't know what I'm talking about, have a look at some of these FPV videos.
FPV stands for First Person View, and simply put, means video piloting, or flying the aircraft from the perspective of an onboard video camera, and wireless downlink. FPV piloting is what makes these videos possible.
When I first saw this kind of flying several years ago, I was compelled to try it myself and ran out and built a 450mm FPV quadcopter. I soon realized that controlling these things was harder than I'd anticipated and I crashed a lot. Nearly every time time I crashed, I had to repair something. Anxiety over crashing ended up preventing me from pushing my limits and developing better skills. I ended up shelving the hobby for a year or two.
This year I decided to get back behind the sticks and refresh my skills with a cheap toy micro quad, and I now recommend this as the first step to anyone who asks me about getting into quadcopters. All of the skills that you acquire flying a toy quad will transfer directly to any multirotor that you fly. The truth is that crashing is just part of learning to fly, and one great thing about micros is that they are seemingly crash proof. They just don't weigh enough to damage themselves much. You don't need acres of empty land to safely fly them, you can do it pretty much wherever and whenever you feel like it, which makes it possible to rack up lots of practice time quickly.
When you've got the hang flying LOS, and you're ready to try FPV, you can turn your micro quad into an FPV trainer by adding a micro camera and a video transmitter module.
Ready-to-fly FPV micro quads
You'll find that there are several micro quads available that are already set up for FPV such as the Walkera QR Ladybird V2 FPV or the Hubsan X4 H107d. These both come with cameras and video transmitters already installed, and feature video displays built right into the RC controllers. Both great flying quads, but their value as true FPV machines is a bit overstated. The cameras that come with these packages do not really have a wide enough field of view for comfortable FPV piloting, and they are angled downward, which makes the situation even more difficult. The video transmitters are only 10-20mw and the antennas minimal. This is going to make for pretty marginal video with short range, and looking down at the little transmitter display to see is not going to make for a very immersive experience.
By choosing your own airborne and ground station components, you will be able to put together a much higher performing and easier to use micro FPV rig that will grow with you as you move on to bigger quads.
The ground station
To fly FPV, you will need a video receiver, and a way to display the video while you fly. This equipment is known as the ground station. Ground stations can be as elaborate as a channel 7 truck, or as simple as video receiver connected to a small LCD screen.
Screens are cheaper, but I find that goggles make for a much more immersive experience. I am using a Boscam RC305 receiver, which sells for around $30, and a set of MyVu Crystal video glasses, which can be found on ebay for $100-$200. The $429 Boscam Skyzone FPV goggles feature 2 built in receivers (RX diversity) and an external camera so that you can see without taking off your goggles.
Collect the parts
To build your micro FPV quad, you will need the following components:
• Micro quadcopter
• Wide angle nano video camera
• Boscam TX5823 video transmitter module
• Lightweight circularly polarized video antenna
• Voltage regulator (may not be needed)
You'll also need a soldering iron.
There are lots of micro quads available, most of which would make a fine platform for a your FPV trainer. I favor the Walkera Ladybird style quadcopters for this project because they are lightweight and the square shape of the frame provides a nice place on the underside to mount the video transmitter. I chose to use the Vitality H36, which is one of many cheap Ladybird clones. The authentic Ladybird is certainly a higher quality quad, but the H36 was a better choice for me, because it is compatible with my Turnigy 9x radio. The ability to fly your micro using a "real" transmitter has the advantage that can use your radio's software to tune the flight characteristics of the quad to suit your style, and make it easier to fly. And the muscle memory gained while flying will be directly applicable to other quads that you fly using the same transmitter. Another cool possibility if you want to use your own sticks, is the HK Q-bot micro quad, which instead of a traditional controller, comes with a little radio module that plugs into any transmitter that has a trainer port.
The TX5823 200mw video transmitter board is available in several variations, and sells for around $15-$20. Some have internal voltage regulators and are capable of running on a 5 volt supply, but most require 3.3 volts. It's not easy to tell which version you actually have. You sort of have to trust the supplier's word. I found the regulated version at FPVHobby.com.
The boards also come in several different frequency bands. Make sure that the TX5823 that you buy is on the same band as your video receiver. If you are purchasing a new video receiver, the Boscam RC805 would be a wise choice, since it can recieve all of the bands.
For the best FPV experience, you want to use a camera with a wide field of view. 120 degrees is ideal. The other important consideration is weight. With this tiny quad, there is no room to fudge and try using an 808 keychain camera just because you have one lying around.
I found this 3 gram wide-angle camera on ebay for just over $30
The spec sheet that came with the video camera says that it requires a supply of 5–9 volts. The regulated TX5823 takes 3.3 – 5.5 volts. The supply from the quadcopter's battery ranges from 3 to 4.2 volts as it discharges. To satisfy both devices I am using a 5v step up regulator from Pololu.
If you are not able to find the 5 volt version of the TX5823, or if your camera takes a different voltage, you may have to use a separate regulator for each device. Pololu makes a wide variety of really tiny step-up and step-down regulators.
The dipole antenna that comes with the transmitter will work, just not very well. To get good range and clear video you'll need to make a lightweight circularly polarized antenna [Video Link]. Making these antennas is it's own fun little project that you watch a tutorial here. The difference is that for this project, you will not use an SMA connector, but solder the antenna directly to the transmitter.https://www.youtube.com/watch? v=JGm9ESx4yzE
Put it together
To mount the camera, I cut a 1'' section of some small fiberglass tubing that I had in my scrap box and slotted it fit over the circuit board and glued it in place with a drop of Gorilla glue.
Mount the camera to the boom with 2-sided foam tape. I colored the foam black with a marker for appearance.
Extending the camera out on a little boom like this prevents the quad's motor pods from being visible in the video. It also counter-balances the antenna, which weighs about the same amount as the camera and will be hanging on the opposite side of the frame.
The Pololu regulator came with 2 header pins, which I soldered to the input side of the regulator to facilitate connection to the quadcopter's circuit board later.
Wire the voltage regulator and camera (or camera connector pigtail if it came with one) to the TX5823 module according to this diagram:
If your components are different than these, then your wiring will vary slightly. Refer to the TX5823 spec sheet.
I applied a bit of hot glue to the connections at the board to provide stress relief.
Solder the antenna directly to the board with the center lead to the ANT pin, and the cable shield to the GND pin.
Mount the completed transmitter assembly to the bottom of the quad frame with some double-sided tape. Tie it securely in place with a bit of fishing line. I use fishing line to tie the wiring harness to the frame wherever it intersects. This keeps it neat, and provides stress relief. At some point, you are going to crash into a tree branch, and you don't need any of those wires pulling free from the board.
I tied the antenna cable to the H36 motor wires at the rear to provide support for the antenna. If you think that it could use it, add some kind of extra stress relief to the antenna to prevent it from breaking free of the board during a crash.
I soldered the header pins of the regulator directly to the "+ "and "–" pads of the H36 circuit board at the points where the battery connector is soldered to the board.
Power up the rig by installing a battery in the quadcopter. Hopefully you won't see any smoke.
Fire up your ground station and see if you get a picture! If not, change the channel on your video receiver to match the default channel on the TX5823. If you're not getting a picture, or if you are getting a poor picture, you may need to change channels on the TX6823, by jumping one or more of the channel pins to ground. See the channel and band reference in the data sheet to figure out the channel assignments.
Go Fly it
[Video Link] I have to say, this little bug is a hoot! It's fast, and It feels pretty much like flying a 250 size FPV quad. Fly this around the local park, or around your house, without the fear of crashing or hurting anyone. When you've mastered it and move on to a more capable video making platform, you'll have much of your crashing behind you.