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[top]FPV Basics for Newbies

FPV is an acronym for "first-person view" and is a method used to control your AeroQuad from the pilot's view point. This is done via a camera, transmitter, receiver, and display of some sort in addition to your standard RC equipment. There are many videos of what FPV is like but here is one of our favorite ones from rcexplorer.se:



You should watch this full screen in high-def. He is using a GoPro HD camera for reference.

[top]Top 10 things I wish I'd paid attention to when getting started in FPV

Lesson 1) Start simple. I initially did a ton of research and bought every component I thought I wanted. (OSD, Autopilot, TX, RX, goggles, diversity, antenna tracking, head-tracking, etc.). I spent countless hours trying to get it all working together before I even attempted my first flight. I figured my technical prowess made me somehow immune to the KISS rule and I'd be fine diving in head first. All I accomplished was making myself frustrated.

Eventually, I stripped the system down to the bare minimum (Camera, transmitter, receiver, and LCD screen) and just FLEW (with a spotter, of course). It was AWESOME! I landed the plane, took it home, and added the pan-tilt system, then flew again. Then I added the goggles, and flew again. I learned that each component made the experience completely new again, and even more complex. The downside? It takes a LOT of time. Like most of you, I have a day-job and a family, which means LIMITED time to work on this stuff.

Besides, had I managed to get myself flying with all the gizmos on day-1, I likely would have crashed due to "too many moving parts". Despite having a nearly unlimited budget, and lots of technical prowess in both electronics and radios, I was eventually forced to walk before I could run.

Accept the fact that it's going to take you a few weeks (or months) to get all the toys working, and focus on the small victories.


Lesson 2) The little things matter. A LOT. I really thought the "little things" were for people trying to squeeze an extra half-mile out of their setup, or trying to make the picture just a little more clear. I was dead wrong. It turns out, the little things are the difference between amazing success and complete failure. When someone tells you that you ought to install a filter somewhere, or shield your wires, or move your GPS a little further from your transmitter, DO IT. I learned that these (seemingly) little things can have more of an impact then spending hundreds of dollars on newer / better gear. And in some cases, they're the ONLY solution.


Lesson 3) A lot of this gear doesn't work with each other. Do a LOT of homework before you buy stuff to make sure it's all going to be compatible. (Example, I bought a pair of FoxTech goggles, only to learn that the built-in receiver wouldn't work with my ImmersionRC transmitter!). A little research before my purchase would have saved me a lot of headaches here. It simply did not occur to me that a 5.8ghz receiver might not be compatible with another 5.8ghz transmitter. Another example? None of the head-tracking systems will work with my JR-9503. Choose your gear carefully.


Lesson 4) When deciding whether you should be using 5.8ghz, 2.4ghz, 1.2ghz, or 900mhz -- the answer REALLY IS "it depends".I just couldn't come to grips with the idea that there would be such dramatic difference between these. Here's the rub: There are pros and cons to each (you should do enough research to know EXACTLY what those pros and cons are). But in the end, it really depends on where you happen to be standing. A half-mile in any given direction might completely change your choice. So how do you pick? The truth it, you're probably going to end up trying them all.


Lesson 5) We all dream of flying 15+ miles and zooming around the countryside, but it's not realistic until you've got years of experience. I know, I thought I was immune to this rule too. I figured if I spent enough money and bought top of the line everything, and all the different gear I needed, I'd have my plane flying 10+ miles within a week or two. "Surely", I thought, "the only reason MOST people aren't flying those distances is because of budget, or lack of RF knowledge". I got humbled REALLY quick. My first flight where I flew beyond the range of my spotter was an immense victory (it was probably my 10th flight). I'm still aiming for the 2-mile mark. Set your goals small, and know that big goals mean big-time experience.


Lesson 6) This stuff is actually not that complex, but if you're not comfortable holding a soldering iron, it's probably not for you.Lots of wire cutting, splicing, soldering, and other such fun. At first, I wanted to avoid all that and try to get something that would "just work". After dozens of hours and countless dollars trying to do just that, I picked up a soldering iron a fit of frustration one day and realized it's MUCH easier to just build the things you need than it is to try and find / order everything.


Lesson 7) A little understanding of RF theory goes a long way. Thank heavens I came into this with tons of ham radio experience, so I understood simple concepts like why you don't want to run a transmitter without an antenna, why the orientation of the antenna matters so much, or why 500mw on 5.8ghz is less effective than 200mw on 900mhz. Get your ham radio license and really understand what's in the test rather than just memorizing the Q&A.


Lesson 8) The gear works, but it's not commercial grade by any standard. I was surprised to find that most of this stuff comes straight from China, it's poorly (if ever) documented, and it's really up to you to figure out how to make it all work together. While not the end of the world, it certainly was not what I was expecting to be getting myself into. The fact that the gear is not particularly robust makes it all the more important to spend the time to get it EXACTLY right, and test it, test it, and test it some more.


Lesson 9) To whatever extent possible, try to be alone. I'm not saying you should fly without a spotter (you should have a spotter, especially when you're new). But I learned quickly that if I was with a group, there was a lot of pressure to perform. I learned that my time in the field was best spent when I could spend as much time as I needed on a particular problem, without feeling the pressure of having other folks watching or waiting. Find a wide open space where you can tweak, fly, repeat as much as you need.


Lesson 10) The guys in the online forums are actually super nice and helpful as long as you approach them with the appropriate level of humility. I've been extremely impressed with the community here. Ask your question nicely, provide the relevant detail, and explain clearly the results you are trying to achieve. Then, re-read your post to make sure the problem is well presented before you submit. Be prepared to do a lot of reading (sometimes answers to questions come in the form of long threads). Be understanding if nobody wants to repeat what's already been discussed.


[top]Basic equipment

[top]Camera

As mentioned, you need a camera. You can choose from a wide repertory of different types ranging from a small security camera up to a full sized camera. Things needed to be considered are if you want to record the video on the camera and if it has enough resolution and low light capabilities for your needs. There are other considerations too but generally only a few cameras are considered ideal for FPV and all the sites carry them. You can go out on a limb and get an odd-ball camera too with some success but this isn't recommended. A commonly used camera for FPV is a GoPro Hero HD camera. It has a very wide angle, takes amazing HD shots and supports a live out so you can record in HD while still flying FPV via a lower resolution image. Additionally, it's almost indestructible which is why shows like Mythbusters use it so much these days.

[top]Receiver/Transmitter

You need some way to feed the video from the copter to your display on the ground. This is done via a small transmitter + antenna on the copter and a receiver + larger antenna on the ground. The big things to consider here are what's legal in your country and what will conflict with your radio. In the US, you can use a 900MHz or 1.3GHz transmitter and receiver pair but you need to have your HAM Technician license to do it legally depending on the power output. The huge majority of FPV pilots in the US seem not to bother with the HAM license but we're certainly not going to suggest or endorse that.

You can also use 2.4GHz or 5.8GHz in the US but the current thinking is that if you have either of those and a 2.4GHz radio you will run into interference problems due to the two antennas being so close. 72MHz radio and 2.4GHz video would work for instance. For example, many choose 900MHz so they can use either 72MHz or 2.4GHz if they wanted. Additionally, the lower the frequency, the less interference it gets from objects like you, trees, vehicles, etc. IE: line of sight is a bit less strict.

If you're using an XBee, keep in mind what your various frequencies are. Most XBees work in the 2.4GHz band as well and some users have reported interference problems with their Tx/Rx setup. If you already have a 2.4GHz Tx/Rx setup, you might want to consider getting either XBee Pro 900 RF or the extended range XBee Pro XSC directly from Digi. These both work in the 900MHz band which leaves the 1.3GHz (1280MHz) band open for FPV.

[top]Display

This is where you view the image being transmitted from the copter. There are a lot of options here and there is some debate as to the best. Almost holy war level in fact. To that end, your major choice is between a small monitor (LCD or CRT) that you look at and head-mounted video goggles.

The cheapest alternative is to buy a small TFT display, (e.g. 7 ") which should have a minimum resolution of 640x480 pixels. It's recommended to mount it in a small box in order to avoid reflections. It is a convenient but not very practical solution.

Of course the video goggles give the best experience by far as it really feels like you are piloting your AeroQuad.
The two most popular choices are between the FatShark goggles and the HeadPlay goggles. FatShark goggles are easier to set up and use, a bit more "plug and play" but they are also lower resolution than HeadPlay. The HeadPlay goggles are able to interface lots of things like computers and play movies off USB drives, etc. They are higher resolution but also harder to set up. The HeadPlays do not support PAL for FPV well - when the signal gets too weak, they simply cut out instead of showing a noisy signal. They also have better diopter support for those who need glasses, but all in all both choices are likely good and it depends on your individual needs. Apart from these two the following video glasses are also frequently used in the FPV scene and have proven themselves:
  • Z800 Emagin
  • Zeiss Cinemizer
  • Video HR i-glasses
  • Fatshark Dominator
  • Headplay Visor


[top]Extended equipment

We only want to stick with the minimum with this guide here and so here is just a short overview of advanced options for FPV.

[top]Patch antenna

This is a simpler, faster and cheaper way to get more coverage, if you are flying in the antenna's direction. A 9dBi patch antenna has an approximately 2 to 3 times higher range than a standard antenna, but still has a large reception area (60 °).
Most people start with a patch antenna and remain at it because this is just great for FPV.

Not all patch antennas are alike. Most commercially available units use circuit board technology because they are cheap to produce. Unfortunately, the advertised 9dB gain is impacted greatly by the cable and connecting means to the receiver. A large majority of these designs only produce a 3dB gain when cable connections are taken into consideration. Fortunately, patch antennas are easy to build. By using common materials and paying attention to details, a patch antenna with a true 8dB gain can be easily constructed for about $10USD. http://rc-cam.com/gp_patch.htm is a step by step construction article that is easily followed with scaling instructions for different operating frequencies. In our forum you can find a build example.

[top]OSD

OSD is the acronym for "On-Screen-Display". It overlays text or graphics directly on the video stream in real time and provides important information about the quadcopter.

[top]Head tracker

The head tracker is a device that converts the movements of your head into servo movements. There are a few different devices on the market which are simply mounted directly on the head (e.g.: on a cap). Movements of your head are converted by acceleration or magnetic field sensors into a PPM signal sent to the remote control.

[top]Antenna tracking

Some OSDs offer the possibility of antenna tracking. Therefore one must buy the right module for the ground station. There you need a "Pan/Tilt"-unit driven by two servos which adjusts an antenna with high gain (e.g. a patch antenna) so that it always focuses on the quadcopter.
The antenna trackers use the GPS data of the OSD to align the antenna always to the aircraft. Thus, an antenna with a higher reception gain (e.g. 14dBi) can be used because the smaller reception area is no longer a problem due the tracking. But consider that tracker antennas are relatively expensive and not easy to build.

[top]Diversity

Video Diversity Controllers are devices with which you are able to connect 2 video receivers. The unit automatically selects the receiver with the best video signal and passes it to the video output. There video goggles, a display or a recording device can be connected. This means that it can be used for the following purposes:
  • Minimize the "dead" area of a single receiver
  • Using 2 patch antennas for extra coverage
  • Use of a patch antenna for longer range and a rod antenna for 360 ° in the vicinity
  • Using 2 different video frequencies


Especially if one intends to fly around fast, deep and close, a diversity set offers the ideal way to get a good signal nevertheless. Diversity controllers are generally somewhat expensive, but since the introduction of the EagleEyes they have become more affordable.

[top]Pan/Tilt camera mount

You can either hook up the pan/tilt servos directly to your receiver to have full control about your camera's FOV or use the onboard camera stabilization (for further information about this possibility visit this page).


[top]Specifics

OK, so we've covered the theory and basics, so now we'll jump into the specifics of an example configuration, where to get the parts and how to set it up.

Transmit/Receive gear:
Cameras:
Video Goggles:
Miscellaneous (connectors, filters, etc.):
  • Ferrite Rings - $1.99-$2.39
    Wrap power cables through ferrite rings to reduce RF noise - particularly helpful when placed between battery and OSD and vTX. Additionally, add a 100uF capacitor after the ferrite ring to create an LC filter (inductor-capacitor), reducing RF noise even more.
  • LC Filter - $12.95
    Use this LC filter if you do not want to make your own with a ferrite ring and capacitor.
  • Deans to 2.1mm power adapter - $10
    You can make this one yourself or just buy it. This lets you power the receiver off of a battery.
  • Zippy Compact 500mAh 3S 25C LiPo battery - $5.89
    It's best to use a separate battery to power your vTX - your main flight battery will drop in voltage as it loses capacity, powering a vTX from your main battery will cause the vTX output power to reduce over the course of the flight.
  • Wire, Dean's connectors, etc. Depends on how you want to go but shouldn't cost you more than $20.


Total is less than $600 which is pretty reasonable for such an amazing experience!


[top]Connecting elements

[top]Wiring the HeadPlay Goggles to the receiver and powering them

Getting the goggles to display the receiver output is trivial, the provided cables are enough to wire the two together no problem - just use the RCA jacks to finish it.

We suggest to wire up the whole system to a single 3 cell LiPo battery so you can run it for hours in the field. To do this, go to Radio Shack with the HeadPlay "Liberator" (it's the big black box the goggles connect to) and have them find a plug that matches the power adapter plug. It won't be a perfect fit, but it will be more than good enough. Make sure the polarity is correct and attach a cable that goes from the radio shack plug to a connector that works with your battery. We also suggest making a little "Y" adapter so you can use one battery to run both the receiver and the HeadPlay goggles at once. Make sure you use a LiPo battery saver on the battery - ideally it will go off before voltage drops and you lose inbound video but test this to be sure.

[top]Wiring the Transmitter to the Camera

This is a touch trickier. Using theGoPro cable linked above you need to connect the GoPro to your transmitter like shown below.

Code:
GoPro --------------------------------------- Transmitter
Brown (ground) --------- battery neg -------- Black (ground)
Orange (video) ------------------------------ Yellow (video in)
White (left audio) ----- 1.5k resistor ------ White (audio in)
Red (right audio) ------ 1.5k resistor ---/
------------------------ battery pos -------- Red (battery in)
Couple of interesting things here. Basically you are tying the ground of the transmitter and camera output together and wiring it to a battery. Finally you are powering the transmitter with that same battery directly. Where "battery neg" and "battery pos" is shown, a male Dean's connector was wired in so this could be plugged right into the distribution bar.

The two resistors are needed to convert a stereo signal into mono without swamping the audio line. The 1.5k ohm is an arbitrary guess, people suggest from 1k to 2k - your call on what to use. Basically you take the white from the camera and solder on a resistor. Then take the red from the camera and solder on a resistor. Now take the two unused resistor leads and solder them together to the white on the transmitter. Presto - stereo into mono.

Obviously you need to be very careful with this as you could fry both the camera and the transmitter if you are sloppy. Go slowly, think it through and be sure all the wires are what you expect. It is NOT guarantee that this diagram is correct, so use at your risk and do your own research to be sure.


[top]Patching For Fun and Profit

Ok, two more things you need to do before you are good to go. The GoPro Hero camera needs to be patched to the latest software release. This is needed so you can get both recording and live-output at once. This is quite simple, go to this page (GoPro HD Hero 3) for the download and instructions.

You also need to patch your HeadPlay goggles to a specific version, 1.18r. This version prevents the HeadPlay from dropping to a "blue screen" when the signal gets too noisy. Not ideal normally but extremely useful for FPV. This way you will see some static frames but no full on loss. Go here to get the patch and see how to apply it (the site is in Russian, you might want to use a translator). If you are using PAL, you should use "FPV Pal Fix 60Hz Firmware" found in the previous link.




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