The components of an FPV Quadcopter


Quadcopter Components

While there are many options for store bought quads, nothing compares to hand built open-source quads.  Hand built quads can be built for thousands less than store bought quadcopters and their performance is the same or better.    There are many options out there and many things that can make a quad unique.  This post is intended to be a very basic guide to the components of quadcopters for beginners.  If you just saw someone at the park flying and want to learn more about their craft, or if you are new to the idea of a custom quadcopter than this post is for you.


 

Quadcopters consist of several different systems and subsystems.  These systems include flight control systems, First Person Video systems (FPV), Power systems, On Screen Displays, Navigational systems, radio systems, and more.

I really like mini quadcopters (250 mm) and this page focuses mainly on that size quad.  A 250 quad measures 250mm diagonally from the back left motor to front right motor. 250 sized quads are great because they are small, agile, and fun to fly while packing the same electronic systems that their larger cousins have been known to carry.  A 250 revolution has begun and they are fast becoming the most popular quadcopter available.

Please look at the diagram above and then click on a tab below for more information on a specific component.

Click on a component below for more information about it.

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[su_tab title=”Flight Controller”]

Flight Controller

The Flight controller (FC) is the brain of the quadcopter.  It is the central computer that processes what the sensors are reporting and makes corrections to motor speeds to keep the quadcopter stable.  [wolf_col_4 class=”first”] Most Flight controllers such as the Naze32 contain the sensors needed for flight, and offer a compact solution for multi rotor design. The right flight controller is really a matter of preference.

 

 

My favorite flight controller is the Naze32.  This FC features an STM32 32-bit processor and comes in an acro version and and full version.  The full version features a barometer, compass, accelorometer, and gyroscope.  The acro version omits the compass and barometer which is not typically used on small acrobatic quadcopter. The Naze 32 can be used in many different configurations (up to an octocopter).  It also does FrSky Telemetry, Multiwii serial protocol, and can control a camera gimbal control.  It is the board that I use the most.

There are some other flight controllers on the market such as the DJI Naza, 3dr Pixhawk, CC3d, and Arduino running multiwii.  Going into the various differences between the controllers is beyond the scope of this article, but I will do a comparison in the future.

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[su_tab title=”Motors”]

Motors

The motors extremely important in a multi rotor setup.  in a quadcopter setup, if a motor fails, the craft will crash.  There are a multitude of motor choices out there, but the best motors that I have found for mini acrobatic quads are Cobra motors and Titan Motors.

 

These motors are brushless, fixed-magnet motors with the magnets in the bell housings.  They require an AC speed controller (ESC) to operate.  Due to the nature of the construction of these motors, it is very important to use motors that have been proven.  The magnets spin in these motors and some motors of lesser quality have been known to loose magnets at high speeds. See my motor comparison here to learn more. [/su_tab]

[su_tab title=”Electronic Speed Controls”]

ESCs

Electronic Speed Controls are required when using brushless motors.  These speed controls offer the advantage of precise motor control at high amps which is essential for stable flight.

 

 

Electronic speed controllers take a PWM (pulse width modulated) input and convert it to 3 phase [su_tooltip style=”green” shadow=”yes” rounded=”yes” title=”A/C”]alternating current[/su_tooltip] to operate the motors.  The ESC has a computer chip on it that makes motor control decisions.  The SimonK firmware that everyone is talking about essentially increases the refresh rate of the speed control so that they react fast enough for acrobatic flight.   [/su_tab]

[su_tab title=”Batteries”]

Batteries

Batteries are what makes it possible for these machines to work.  Not just any battery will do.

These craft draw a high amount of amps and therefore an high discharge Lithium Polymer battery is needed.  It is not uncommon for a small multi rotor such as the QAV250 to draw over 30 amps at full throttle. Large quadcopters can draw over 150 amps! [/su_tab]

[su_tab title=”Propellers”]

Propellers

Propellers are very important for flight.  Not only do you have to make sure that you choose the right propeller, but their stiffness can effect flight, their balance can effect flight, and their pitch can effect flight.  The propellers on a quadcopter all rotate in different directions so you have to use 2 props with a clockwise rotation and 2 props with a counter clockwise rotation.

Choosing the right propeller is important, but luckally, they are cheap and they work well.  GEMFAN 5030s are a popular choice for mini rotors.  The first two numbers represent the diameter of the prop and the second two represent the pitch.  A 5030 is 5 inches in diameter and 30 [/su_tab]

[su_tab title=”BEC”]

BEC

Battery Elimination circuit is a fancy way of saying “Voltage regulator”  Most of the time you can find this included with an ESC, however, ESCs are noisy, and they have been known to give off an unclean voltage.

When in doubt, It is wise to use a separate BEC to supply 5v to your flight controller and other 5v electronics.  This can help eliminate noise in your power supply which can cause control problems and poor quality video.   [/su_tab]

[su_tab title=”Radio Receiver”]

Reciever

A radio receiver is essential for reliable quadcopter operation.  This is the device that picks up the signals from your transmitter and communicates those commands to the flight controller.

There are several choices when it comes to a radio receiver.  Many radio transmitters come with receivers, and there are many many choices when choosing a good radio system.  I recommend FrSky 2.4 GHz systems with Telemetry, or DTF UHF for long range.  The FrSky system is good up to 1.5km.  A UHF system can work for miles. [/su_tab]

[su_tab title=”Frame”]

Frame

A good frame is essential.  There are many factors to consider when choosing a frame.  Good build quality is important.  So is material choice.

I recommend a smaller frame such as a qav250 for a beginner.  These small frames weigh less and therefore they tend to break less when crashing.  Other things to consider are weather to use carbon fiber or some other material.  Carbon fiber is very strong but there are some downsides to using it because it is a conductor and can interfere with antenna operation.  It is also very expensive to manufacture and is known to delaminate on impact. My opinion is that G10 fiberglass is the best frame material for FPV crafts. [/su_tab]

[su_tab title=”Video Transmitter”]

Video TX

FPV quad copters use a video camera and separate video transmitter to get the image of what they see to the ground.  There are many popular choices in terms of brands and frequency selection.  The most popular for mini rotors is the 5.8ghz band.  This band offers a ton of channels and not much competition with other devices.  A popular choice is the immersion R/C 600mw video transmitter.  This offers a good amount of power and works with the popular fatshark goggle frequencies.

There are many varieties available when choosing a video transmitter and you have to consider the type of flying you are doing, The amount of power that you need, and the frequencies that you can pick up on the ground.  The 5.8ghz band is great because of the small antenna size and compatibility with Fatshark Goggles.  More to come on this topic. [/su_tab]

[su_tab title=”FPV Video camera”]

FPV Camera

FPV quad copters typically use a separate, low definition CCD or CMOS camera for the video link to the pilot.  While some people use the direct video output from a GO Pro or Mobuis HD camera, This is overkill and the field of view, slow reaction to lighting changes and high definition of these HD cameras is not ideal for piloting.  Current FPV quadcopter use standard definition video downlinks, and this will most likely be the trend for a while.

The Sony Super Had CCD is an amazing choice for FPV Pilots. It’s price and performance beat all of the other cameras out of the water.  The camera choices are unlimited but there are a few tried and true cameras used like the ones pictured.    [/su_tab]

[su_tab title=”FPV Goggles”]

FPV Goggles

FPV quad copters require a way to view the image on the ground.  While some people use regular monitors,  the critical device that makes this machine really possible is FPV goggles.  Goggles such as the Fatshark Attitude have a built-in video receiver and can receive the video signals from video transmitters on the craft. [wolf_column col=”col-8″ first=”yes”]

 

 

 

 

[/wolf_column][wolf_column col=”col-4″ last=”yes”]Again, there are many choices for goggles, but the best are the Fatshark Attitude, Dominators, or Boscam Skyzone.  It comes down to your pocketbook and your personal preference.  The Fatshark goggles don’t work with bosom gear without modification and vice-versa, so you need to make sure that your goggles match your video transmitter. [/wolf_column] This is one item that you shouldn’t skimp on, as it is the only thing linking you to your aircraft.  [/su_tab]

[su_tab title=”LC Filter”]

LC Filter

LC Filters are used to filter the power for FPV Video.  Without them, the noise from onboard electronics can get into the video feed of an FPV quadcopter.  They are essential for any single-battery FPV setup.

Dirty power can lead to horizontal lines in your video which is hazardous and will lead to loss of control.  My advice is to do it right and plan to use an LC filter with any FPV build.[/su_tab]

[su_tab title=”Video Transmitter & receiver antenna”]

Video Antennas

Receiver and transmitter antenna technology has come a long way.  The most popular multi rotor antenna right now is the circular polarized skew planar wheel or cloverleaf antenna.  Aerial Video Systems is one brand that is known for quality, and his antennas are beautifully built, and pricy. I recommend them for a first time flyer, but as you advance in the hobby, you will probably realize that you can build your own antennas for much less.[wolf_column col=”col-4″ first=”yes”]

 

 

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[wolf_column col=”col-8″ last=”yes”]In the world of antennas, there are always trade offs in terms of power, and range.  for park flying, a cloverleaf antenna on the receiver is fine, but if you want to get out of the park, a directional antenna on the receiver such as a helical antenna becomes mandatory.

There is a tradeoff between the two.  There are systems such as diversity controllers that allow you to use 2 or more antennas to get the best of both worlds, and things such as antenna trackers, but going into those is beyond the scope of this article.

for a new pilot, you can’t go wrong with the IB crazy antenna set.[/wolf_column] [/su_tab]

[su_tab title=”Radio”]

Radio

Radios are the controls at your fingertips.  They are very important, but really come down to personal preference.  The Frsky Taranis is a brilliant choice, but the turnigy 9x is also very good if you are looking for a bang for your buck.  I fly a 9x, modded with OpenTx and Frisky & DTF UHF openlrsng transmitters.  This works for me because I am a hacker.  If you aren’t a hacker, get the Taranis!!!

Again, radio choice comes down to preference.  The most important thing to remember here is to find one that you are comfortable with, on 2.4ghz or one that outputs a PPM signal for use with an external radio.[/su_tab]

[su_tab title=”Transmitter”]

Transmitter (TX)

Not to be confused with the radio,  The transmitter is the actual wireless part of a radio.  If you have a PPM output radio, you can choose any transmitter that you want.  That is how the FrSky and DTF UHF systems work.  You simply supply them with power and a ppm signal from your radio and they send that signal to the receiver.[wolf_column col=”col-4″ first=”yes”]

 

 

[/wolf_column][wolf_column col=”col-8″ last=”yes”]Again, radio choice comes down to preference.  Both of the transmitters listed here feature telemetry which is useful for receiving data back to the radio such as battery voltage. [/wolf_column][/su_tab]

[su_tab title=”GPS”]

GPS

GPS (Global positioning system) consist of a chip and antenna.  Different flight controllers and On screen displays feature gps capabilities.  These allow you to monitor things like speed, altitude, distance from home.  Unlocking features such as position hold, return to home, and displaying lost location on a map.[wolf_column col=”col-4″ first=”yes”]

[/wolf_column][wolf_column col=”col-8″ last=”yes”]Many stock GPS units such as the UBLOX CN-06 are a good choice, but they have to be updated to a higher refresh rate (from 1 hz to 5hz) and baud rate for use with Multicopters.  This can be done with software. It is very important to remember that compass functions are an essential part of GPS operations.  If you are trying to add GPS capabilities to a flight controller without a compass built in, you will have to use a gps with a compass.  The Naze32 will work with a CN-06 because the compass is on the Naze32, however the Naze32 ACRO does not have a compass and therefore a GPS with a built in compass is needed.[/wolf_column] [/su_tab]

[su_tab title=”OSD (On Screen Display)”]

On Screen Display (OSD)

This board is what takes information about the quad copter such as pitch, heading, position, navigation, battery voltage, speed, altitude, etc and overlays that information onto the screen.  It allows you to be fully immersed in your piloting without having to look at anything other than your video feed.  OSD is essential for the full experience.

There are many different options when choosing an OSD, however, the minimosd is a fantastic value if decide to tweak it a little bit.  This is my go-to OSD and I use KVTeam OSD firmware to give me all of the functions that higer priced boards have at a fraction of the price.   [/su_tab]

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